nvac greenhouse final report

Natural Ventilation Augmented Cooling (NVAC) Greenhouse:

Construction of a Greenhouse, Establishment of a Plant Growth System and Greenhouse Microclimate Analysis at the Bellairs Research Institute.

FINAL PROJECT REPORT

AEBI 427 Barbados Interdisciplinary Project

Rhys Burnell

Rachael Warner

Jessica Xavier

Presented to:

Dr. Danielle Donnelly

Natural Ventilation Augmented Cooling (NVAC) Greenhouse

June 20, 2016

Contact Information:

Rhys Burnell [email protected]

Rachael Warner [email protected]

Jessica Xavier [email protected] Skype: jessica-c-xavier

Mentor: Lucas McCartney [email protected]: lucas.mccartney

Location: Bellairs Research Institute, Holetown, St. James Parish. Barbados

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Table Of Contents

1. Acknowledgements 5-8

2. Introduction: 9-20 Food Security in the Caribbean Community and Common

Market (CARICOM) Caribbean Food Security in Barbados Protected Agriculture in the Caribbean Tropical Greenhouses - Cooling and air circulation:

o Naturally Ventilated Roofo Fan and Pad Cooling Systemo Roof Evaporative Coolingo NVAC Tropical Greenhouse

Hydroponic System & Growing Medium Site of Greenhouse Construction: Bellairs Research Institute Project Overview Selected Cultivars & Environmental Requirements Pests and Diseases Fertilizer Mix

3. Objectives / Working Plan: 20-23 General Objectives Specific Objectives

4. Calculations and Results: 24- Minimum Start-Up Power Sequence For Pump Total Daily Water Usage In Greenhouse:

o Hydroponic System o Misting System o Total Daily Water Usage

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5. Timeline

6. Materials

7. Progress Report: Construction Plant Health Water

8. Data and Analysis: Graphs 1 to 14 Discussion On Graphs

9. Appendix 1: Photos and Figures

10. Appendix 2: Data

11. References

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1.

Dear Lucas,

We would like to extend a big sincere thank you to you for your role as a mentor in our AEBI 429 project this summer. All three of us were both honored and enthused to have the opportunity to work on the NVAC Greenhouse on the Bellairs campus. The project was not only challenging in the best way possible but it allowed for significant professional and personal growth for us as McGill undergraduate students. In participating in such a hands on sustainability focused project we were able to gain a better appreciation for the field of bio-resource engineering. The project also gave us a better understanding of the complexity associated with the planning and completion of projects related to the pillars of sustainability. Your leadership was both constructive and friendly, as you guided us through every step in the project while taking time to ensure that we were grasping the fundamental concepts and reasoning behind every stage. I believe we all took away slightly different but just as positive learning experiences, owing to our differing academic backgrounds. In fact this was one of the strengths of our project group, including yourself as a mentor, is that all opinions were valued and there was an appreciation for our different specialties There was in fact a utilization of this diversity in knowledge to more efficiently complete the project. We thank you again for allowing us to be part of this most important project and we hope that we were able to contribute positively to the focus of your PhD. We wish you the best in your future endeavors and look forward to hearing about the progression of the NVAC Greenhouse model.

Cheers Lulu,

Jessica Xavier, Racheal Warner, Rhys Burnell

Dear Doctor Donnelly,

As the NVAC Greenhouse Team we would like to thank you for your important role over the course of this research project. You were invaluable in guiding our project and providing important advice in times of challenging obstacles. Your constructive criticism drove us to keep striving to better our understanding and motivated us to achieve our very best. We are extremely reconnaissant to you for the planning of this project and your involvement throughout the summer. We hope that we were able to meet your expectations for the success of the Bellairs NVAC Greenhouse and we wish you all the best in the future. It is thanks to you that we were given the opportunity to be part of such a formative experience, one that we will take with us in all of our future academic undertakings.

Sincerely,


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Dear Susan,

As the NVAC Greenhouse Team for the summer of 2016, we would like to take this opportunity to thank you for allowing Lucas McCartney and ourselves to carry out the construction of the NVAC Greenhouse on the campus of Bellairs. Giving us the space and resources to do so was paramount in the realization of this project. We hope that the completed greenhouse meets all of your needs and will be of value for Bellairs in their goals to further their environmentally sustainable ways. We look forward in keeping up with the NVAC Greenhouse at Bellairs and hearing about it’s role in providing local produce for the on campus cafe and cooking staff at Bellairs. Once again, thank you for your investment in the project and we hope the benefits stemming from the inauguration of this greenhouse are noteworthy.

Sincerely,


Dear M. Smalls, M. Rowe, and Kevin,

We would like to take this opportunity to extend a sincere thank you for your help and important role in the construction of the NVAC Greenhouse at Bellairs. Your interest in the project and constant support in terms of equipment, knowledge and advice, was heavily felt and appreciated. We consider all three of you to be crucial in the completion of the greenhouse and in its continuation as a source of local produce. Along with Lucas McCartney, you were guiding forces and were there in challenging times, keen on ensuring the success of the project. We hope that you are pleased with the final result and that the greenhouse is easily manageable and exponentially successful in producing food for the Bellairs Research Institute. Thank you again for all that you did and we wish you nothing but success with the Greenhouse as well as in your respective futures.

Sincerely,


2. Introduction

Food Security in the Caribbean Community and Common Market (CARICOM) Caribbean

According to the Food and Agriculture Organization of the United Nations (FAO)'s 2015 report on food insecurity in the CARICOM Caribbean, the Caribbean has made significant strides in reducing undernourishment and contributing to the global target of hunger eradication. In fact, since 1990, the number of undernourished individuals in the Caribbean has decreased from 8.1 million to 7.5 million (FAO, 2015). However, the issue of food production and nutrition, in a comprehensive context, continues to be met with major challenges. In CARICOM

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countries, such as the small island of Barbados, food imports comprise 80% of the provisions sold on the market (FAO, 2015). Studies suggest that grocery stores and affiliated warehouses in the Caribbean rarely have access to more than 4 weeks of food supply at a time and spend roughly 23% of their export revenue on food imports (FAO, 2015). As for the remaining 20% of food items circulating in the West Indies, it is estimated by the Caribbean Network of Farmers (CAFAN) that over half of that supply is produced by small scale family farms (CARICOM, 2010).

Food Security in Barbados

Barbados is forced to sustain large annual food bills of approximately $347 million due to their present lack of food sovereignty (Ministry of Agriculture Barbados, 2012). In fact, from 2007 to 2008, a 33% increase in the country's food bill was noted (Ministry of Agriculture Barbados, 2012). Since 2002, national trade statistics have recorded an increase of approximately 10 % per year on all food imports (Ministry of Agriculture Barbados, 2012). Characteristic of a small island developing state (SIDS), it is situated in a zone with statistically important occurrences of natural disasters, and as mentioned above it is highly dependent on imported goods due to insufficient local production (Rawlins, 2003). This makes it incredibly vulnerable to these aforementioned fluctuations in the global market. Compounding these issues are the challenges associated with food self-sufficiency, one of these being limited arable land. While this SIDS encompasses 432 km2, only 20,000 ha are available for agriculture, with most of the land mass sold to lucrative tourism operations (Rawlins, 2003). Water scarcity is another major issue with which Barbados is confronted as it is ranked amongst the top fifteen water scarce nations (Rawlins, 2003). Even during the rainy season, much of the rainfall run off is lost to the ocean as there are no rivers or lakes to catch it. Small farming operations, with no governmental ties, are the most disserviced in terms of water shortages as they are forced to pay 2.12 BDS$ per m3 compared to the few large farming operations that are given markdown prices of 0.33-0.44 BDS$ per m3. This is significant seeing as 90 % of farms in Barbados operate on 0.5 ha or less. Perhaps most noteworthy is Barbados’ struggle to compete with international agricultural production. Due to the islands production limits imposed by its geographic and demographic sizes, farmers are limited in the technologies available to them. Not only are their agricultural products deemed uncompetitive on an international scale, but even amongst the CARICOM countries, Barbados is rivalled by countries with more energy available to them, larger work forces and a larger resource base.

Despite these contentions, self-sufficiency in food production is paramount and needs to become a national priority for the island of Barbados. This became especially evident after the events of September 11th 2001 when supermarkets in Barbados experienced an extreme drop in food stocks as a result of halted trade. This scare prompted a national food security plan which involved increasing local food product competitiveness through better quality and niche

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marketing. The plan also promised to support consumption of local produce by aiming to have 60 % of vegetables sourced locally (Rawlins, 2003). It is by achieving a better balance between importation and domestic production that Barbados will acquire a certain level of food security.

Concurrently, this presents an opportunity for growth of localized farming as well as proposes an alternative to a high degree of imported products. Investing in this island’s food production, not only ensures a level of self-sufficiency that is crucial in light of Barbados's status as a vulnerable SIDS, but could also help mediate new sweeping trends in high fat and high sugar diets, which are being linked to a sharp increase in metabolic diseases within the Caribbean (FAO, 2015). Introducing domestic fruit and vegetable crops, as primary constituents in Bajan markets and supermarkets, could be highly beneficial in dissociating from imported processed and nutrient poor foods (FAO, 2015). Making large quantities of plant foods available offers the possibility of addressing Barbados's rank as the country with the highest rate of female obesity in the Caribbean (67.6 percent) and as amputation capital of the world as a result of untreated diabetes (FAO, 2015).

Protected Agriculture in the Caribbean

If there is to be a focus placed on increasing local food production, a number of agricultural practices and structures need to be investigated and amended. Von Zabeltitz (2005) highlights heavy rainfall in the rainy season, high relative humidity levels, wind damage, and temperatures above 30 C as impeding factors on traditional agriculture in the global south. Greenhouses, classified as a form of protected agriculture, have been valuable in addressing these issues. Not only are they typically more productive but they answer to the question of restricted land access (CARDI, 2014). Greenhouse structures also provide shelter from Barbados's arid climate and high average temperature of 27 °C, while protecting crops during the rainy season which extends from June to December (FAO, 2000). Finally, protected agriculture is arguably the most valuable for its provision of shelter from pests and disease. This is particularly true in subtropical and tropical regions, such as Barbados, where the climate favors biodiversity and consequently pest organisms. To summarize, greenhouses have proven to increase yields, improve the quality of crops, address restrictions in terms of land availability and use, reduce water usage, increase control over fertilizer usage, decrease the need for pesticides, and finally protect plants from weather extremes (USAID, 2008). However, while typical greenhouses eliminate some challenges such as pest infestation, wind damage, soil erosion and soil leeching, their heat-retention proves to be unfavorable in tropical climates such as that of Barbados. Lack of guttering or other water catchment (which encourages problematic algae growth on covering surfaces), and light blockage during times of limited sun exposure, most notably in the rainy season, also add to traditional greenhouse drawbacks in Barbados, and the Caribbean at large (CARDI, 2014).

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Tropical Greenhouses: Cooling and air circulation

Naturally Ventilated Roof

Naturally ventilated roof systems are ideal in tropical environments, as they increase air flow and reduce temperature. Conventional greenhouses have solid roof construction, to restrict any air from escaping, these are ideal for temperate climates. In tropical climates, this leads to very high temperatures that can affect plant health. There are different forms of natural ventilation, a variety of popular designs are illustrated in figure 22 (Boulard, et al., 1997). These mainly use ventilation by vents which can be opened and closed. The NVAC greenhouse utilizes a split roof design, this is ideal because it is a simple design, whose construction can be attained with the limited resources found on the island. The ventilation works by utilizing the natural convective movement of air in temperature and pressure gradients. The ideal orientation for a split roof greenhouse is the opening in the roof facing away from the prevailing wind. As the air moves over the greenhouse it creates a low pressure zone in front of the opening in the roof, this draws air out of the greenhouse as it reestablishes a uniform pressure gradient (Sethi, Sharma, 2007). It has been found that the presence of an insect screen in the ventilation opening reduces the amount airflow through the vent and increases the presence of a temperature gradient (Sethi, Sharma, 2007). Although, because of the high prevalence of pests in the tropics, there is no option but to install insect netting to reduce pest prevalence in the greenhouse.’

Due to space constrictions at Bellairs, the greenhouse is not oriented in a way to obtain the optimal benefits from the prevailing wind. Referring to figure 2, we see that the orientation of the Bellairs greenhouse is not idea. The only way to remedy this would be to build the greenhouse in another location, or shorten it and rotate the roof. Even without the ideal location, we still see the misting system and split roof design reducing the temperature in the greenhouse, therefore effectively still doing its intended purpose.

Fan and pad cooling system:

Fan and Pad cooling systems require a high-energy input to run. Fans draw air out of the greenhouses and subsequently, air is drawn across wet pads which are continually being rehydrated (Sethi and Sharma, 2007). As water evaporates from the pads, the air is cooled and this cool air is circulated throughout the greenhouse, via air movement caused by fans. This system requires high energy input, as large motors are used to run the fans, unlike the more economical misting, which uses only two motors to run water pumps (Ahmed et al., 2005). Running only a fan yields no significant change in temperature, but with the addition of wet pads

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temperature is noticeably lower in both the air and the plant canopy (Willits, 2003). Fan and pad systems do not provide equal distribution of cooled air, reducing the homogeneity of the air in the greenhouse (Kitas et al., 2003). Arbel et al. (1999) performed an experiment comparing cooling capacity and homogeneity of the air from fan and pad cooling systems and a mist cooling systems. They found misting led to a greater reduction of temperature and less variation in the greenhouse relative humidity compared to the fan-pad system.

Roof evaporative cooling

This system uses water sprayed onto the exterior of the roof as a cooling system (Kumar, Tiwari, 2009). Like the others, the water evaporates, reducing the temperature of the surrounding air, and results in a uniform effect, like fogging. The downfall is that it requires more water than a fogging system (Kumar et al., 2009) and offers no air circulation to the greenhouse.

NVAC Tropical Greenhouse

Answering to the obstacles of protected agriculture in the tropics is Dr. Mark Lefsrud and Ph.D. candidate, Lucas McCartney's Naturally Ventilated Augmented Cooling Greenhouse (NVAC) greenhouse model. The NVAC utilizes natural properties such as the tendency of hot air to rise and relatively cooler air to sink to create an air flow which ultimately has a cooling affect (McCartney, 2016).

The misting system in the NVAC greenhouse plays two important rolls. Firstly, it cools the greenhouse and secondly, it contributes to air circulation; both of these factors contribute to air homogeneity. Montero et al. (1990) found that misting alone can reduce the internal temperature of a greenhouse by 3-5 °C. Many cooling systems take advantage of the latent heat of evaporation of water, but in the case of the NVAC misting is the ideal system for desired cooling effect, compared to other systems. (McCartney and Lefsrud, 2015).

The novel aspect of the NVAC greenhouse is the third roof, which allows the misting system to have notable contribution to air circulation in the greenhouse. The misting system is placed above the third roof (i.e. the lowest one, see Figure 19), which guides the front of cold air down the side of the greenhouse and allows it to collapse into the growing canopy (McCartney and Lefsrud, 2015). This works due to the change in density of air at varying temperature; cool air is denser than hot air. This leads to a higher specific weight of the cool compared with the warm air, which then leads to sinking. This turbulence contributes to mixing the air. Falling cold air pushes warm air up, and it is vented out of the split in the roof, completing the circulation pattern of air around the greenhouse. The use of a fine mist increases the surface area of the

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water and facilitates high levels and speed of evaporation (Ahmed et al., 2005). Ahmed et al. (2005) were focused on trying to determine a measure for the exact percent value of water that is evaporating to prevent liquid water from reaching the canopy or floor. Mist reaching the canopy and wetting the plants can increase risk of pests, which is highly undesirable in the any protected agriculture system (Albajes, 1999). In the NVAC greenhouse, this will not be an issue as any water which does not evaporate will collect on roof 3, which leads into the gutter system and recycles water back into the 200-gallon hydroponic solution tank (Rotoplastics tuff tank).

Adding to this long list of merits imparted by the NVAC greenhouse model is its simple maintenance requirements, relatively low water and energy consumption, and automated regulation. The misting line is a simple concept and therefore associated maintenance and repairs do not require electrical engineering knowledge. Automated regulators prevent the misting system from operating on cool and rainy days, making water wastage and unnecessary energy expenditure negligible (McCartney, 2016). These are all desirable traits in light of limited financial support and access to energy for farmers in Barbados.

The NVAC greenhouse project at Bellairs Research Institute offers the possibility of being an example of sustainable agriculture in an isolated, energy scarce, tropical setting. Not only will it benefit Bellairs Research Institute to reduce their ecological footprint, but the greenhouse, on a larger scale, introduces a revolutionary solution to the challenging effects of a tropical climate on plant productivity. Introducing this technology to the island of Barbados is sure to make the question of food sovereignty re-surface as one of this country’s priorities. While the Ministry of Agriculture has asked for funding to support local farmers, it has received little aid due to a strong focus on the tourism sector, playing into the minimal 1.8 % GDP contribution of agriculture in Barbados (McCartney, 2015). The introduction of Dr. Lefsrud and Mr. McCartney's tropical greenhouse model to Barbados is important in a broad sense as a milestone in the country’s move towards food sovereignty, a concept defined by Food Secure Canada as "the right of peoples to healthy and culturally appropriate food produced through ecologically sound and sustainable methods, and their right to define their own food and agriculture systems" (FSC, 2015).

Hydroponic system & Growing Medium

The Island of Barbados is mainly made of coralline limestone (83 %), with the remaining fractions being made of shales, sands and clays (17 %) (FAO, 2000). The large proportion of limestone is responsible for the inefficiency of the island to retain rainwater as it is a highly porous medium (Connolly & Trebec, 2010). On the other hand, shales, sands and clays are prone to landslides and soil erosion, issues which have plagued Barbados over its long history of monoculture production systems. Along with water scarcity, poor soil quality is another limiting factor when looking at traditional agriculture on the island. Hydroponics is compelling as an

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alternative production method as it involves growing plants without soil. From the Greek words hydro, meaning water, and ponos, meaning labor, hydroponics replaces soil media with water media or aggregate media (Connolly & Trebec, 2010). That is, nutrients are dissolved in water and plant roots are directly exposed to this water. Hydroponic techniques include nutrient film, ebb and flow, deep water culture and raft techniques (Connolly & Trebec, 2010). Furthermore, within the hydroponics class are alternate media which include organic substrates such as coconut coir and non-organic substrates such as rockwool (Nichols, 2013). Coconut coir (Coconut Coir Growbags, Cocogreen, U.K.) will be discussed at length later in the text as this is the chosen hydroponic medium for the purpose of this project. The basis of this technique is that plants are grown within the coconut coir and water with diluted fertilizer introduced to the rooted plants. Coconut coir is an organic medium that is valued over media such as rockwool and peat by environmentalists and agronomists worldwide. Peat is a limited resource and rockwool has its own issues as far as its high-energy requirements for production phases. Coconut coir in comparison is a product of the coconut palm tree (Cocos nucifera), found in subtropical and tropical regions such as in Barbados. Coconut palm trees are heavily utilized by humans with over 50 million tons being harvested annually. Of that, 25 % of the material is the coconut’s exocarp/ mesocarp or the coconut’s husk; a component comprised of fiber and cork like particles. The fibrous portion was traditionally spun into yarn or used for the making of items such as rugs and mattresses. However, the remaining coconut dust was considered a waste product. This not only contributed to overflowing landfills, but created breeding grounds for disease carrying mosquitos as water accumulated in the coconut coir. Thus the recent usage of coconut coir for horticulture has alleviated some of the problems related to its wasteful disposal. It is estimated that with todays supply of coconuts, 8 million tons of coir dust is produced annually, allowing for 350,000 ha of greenhouses to be sustained. Not only does this organic soilless substrate absorb water and nutrients more readily then rockwool, but transportation of the material is made relatively easy as it is manufactured and shipped in a compressed form. In comparison, rockwool is a bulkier, less porous substrate. Conclusively, hydroponics is an ancient agricultural practice which has been revisited in modern times due to its benefits in areas where soil quality is non-conducive to agriculture. It is also part of the solution in addressing water scarcity in countries such as Barbados and allows agriculturalists to better control fertilizer levels and avoid environmentally harmful pesticide leaching (Connolly & Trebec, 2010).

Site of Greenhouse Construction: Bellairs Research Institute

As detailed below, we are in the process of constructing a tropical greenhouse on the site of the Bellairs Research Institute in St James, Barbados, WI. | Bellairs Research Institute exists as part of McGill University and was donated to McGill in 1954 by Carlyon Wilfred Bellairs (Barbados Museum and Historical Society, 1962). His motive was to create a space in the tropics for scientific research. The campus was officially opened in 1960 by the Prime Minister of the West

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Indies, Grantley Adams. The center’s main focus is on marine biology and offers facilities such as laboratories, aquaria and water tables for culture work. This research has been of use to the island of Barbados which deals with a number of fisheries related problems. Past projects associated with Bellairs Research Institute include studies on migration patterns of the economically important flying fish, as well as research done on the locally known crayfish or fresh water shrimp and various projects looking at inshore currents, animal production and tropical water productivity rates (Barbados Museum and Historical Society, 1962). While marine biology remains the main purpose for the institute’s operations, other fields of study have benefitted from the facility. These include agricultural studies looking at sugar cane production in particular, as well as studies done on land use on the island of Barbados (Barbados Museum and Historical Society, 1962). Bellairs has also welcomed a number of engineers both in the energy sector as well as in Bioresource engineering. This NVAC greenhouse project is a testimonial to that statement as it is under the direction of Lucas McCartney, a Ph.D. candidate and Professor Mark Lefsrud, a professor, both of the Bioresource Engineering Dept. at McGill. Today, the Institute has shifted from solely accepting researchers and graduate students to being the site for undergraduate semester abroad studies (Essert, 2011). BITS specifically offers courses in summer while partnering with the University of the West Indies (Cave Hill Campus), and the National Conservation Commission.

The Bellairs NVAC tropical greenhouse is modelled from Mr. McCartney and Dr. Lefsrud’s patented design. It constitutes a part of Bellairs sustainable food project, implemented in fall 2014. In May-August 2015, McGill BITS students created the cement posts for the greenhouse and constructed the frame out of steel (Curry-Sharples et al., 2015). This frame included the roof members, attached to horizontal cross beams. These BITS 2015 students also installed a third roof and misting line in one of Mr. Simon and Mrs. Sandy Cannon’s several commercial greenhouses at their cucumber farm in 2014 and did some pilot testing there using HOBOware software. The continuation of this multi-tiered project continues this May-August (2016) as we focused on completing all the NVAC Tropical Greenhouse construction steps, installing irrigation and electricity systems, growing the first hydroponic test crop, and collecting data all at the Bellairs Research Institute greenhouse site.

Project Overview

For the summer of 2016, the project consisted of completing the construction of the NVAC sustainable greenhouse at the Bellairs Research Institute and involved data logging as tomato plants (Solanum lycopersicum ‘Heatmaster’), cherry tomatoes (Solanum lycopersicum var. cerasiforme), cucumber plants (Cucumis sativus cv. unknown), swiss chard plants (Beta vulgaris sub. Vulgaris cv. unknown) sweet pepper plants (Capsicum annuum sub. annuum ‘King Arthur’), and chili peppers (Capsicum annuum) were grown hydroponically. Water was also

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sourced sustainably as it was collected from rainwater. Electricity consumption was subsidized by photovoltaic panels located on the roof of the Brace building (McCartney, 2015).

These environmentally friendly elements of the tropical greenhouse align with Bellairs Research Institute's role as an agro-ecological research station and exhibition site. Locating the NVAC greenhouse at this site in Folkestone, Barbados, not only created an opportunity for students such as ourselves and local Bajan farmers to learn about bio resource engineering, horticulture, and local agriculture, but it could also serve as a source of sustainable produce for the campus's cooking staff. This has great potential value as the food bill for Bellairs is estimated to cost a steep $127,000 (BD) annually, with next to 50 % of food items being international imports. Sustainable Project Fund (SPF) funding was used towards project purchases as well as for travel funding for Dr. Mark Lefsrud and Lucas McCartney, who worked with Bellairs staff and BITS students to convey their expertise and ensure the successful progression of the project. Bellairs Research Institute has agreed to support the NVAC greenhouse project by donating the necessary plot of land as well as by arranging for the structure to be taken care of upon the completion of set up. This entails the provision of energy and labor for successive crops of food production following the departure of BITS (2016) students.

Selected Cultivars & Environmental Requirements

As mentioned above, tomato plants (Solanum lycopersicum ‘Heatmaster’), cherry tomatoes (Solanum lycopersicum var. cerasiforme), cucumber plants (Cucumis sativus), swiss chard plants (Beta vulgaris sub. vulgaris), sweet pepper plants (Capsicum Annuum sub. annuum ‘King Arthur’), and chili peppers (Capsicum annuum) were grown hydroponically in the second phase of the project. These are all classified as fruit in horticulture, and have specific requirements for growth. As far as pollination, the selected cultivars chosen for the purpose of this project are self-pollinating, meaning neither manual pollination or insect introduction is necessary. This not only limits the labor necessary to prompt fruit initiation but it avoids having to introduce pollinating organisms which can attract unwanted pests.

The tomato is a herbaceous plant, cultivated annually (Winters & Miskimen, 1967). This member of the Solanaceae family, which groups regular tomato species and cherry tomato species together, does best under cool and dry conditions at elevations below 762 m (Winters & Miskimen, 1967). Both high tropical temperatures and excessive rainfall are associated with reduced tomato yields. Excessive rainfall causes fruit cracking and makes it difficult to retain fungicide coverage (Winters & Miskimen, 1967). The NVAC greenhouse addresses these detrimental conditions by keeping tomato plants in a relatively cool and sheltered environment. Tomato plants can generally be grouped into two categories: determinate low growing bushy plants, and indeterminate types which grow tall when staked and sprawl when not staked (Mortensen & Bullard, 1964). Determinate cultivars tend to fruit in a shorter period of time when

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compared to indeterminate cultivars (Mortensen & Bullard, 1964). Determinate type cultivars also require no pruning. The Heatmaster Hybrid tomato plant cultivar selected for the purpose of the project, as well as the cherry tomato cultivar, are determinate types which require about 75 days to reach maturity (Winters & Miskimen,1967). Tomatoes do best in hot and humid tropical climates and under these conditions produces large fruit. Production can be increased by providing the plants with low nitrogen and high phosphorus levels (Winters & Miskimen, 1967). Calcium is also important in order to prevent the development of blossom end rot, a necrosis of maturing fruit caused by calcium deficiency (Winters & Miskimen, 1967). In the case of the hydroponically reared tomato in the greenhouse at Bellairs, these nutrients will be provided through the irrigation system. The most common viruses affecting tomato plants are the tomato spotted wilt virus (TSWV), a virus transmitted by insects and thrips, as well as tobacco mosaic virus (TMV), resulting from mechanical contamination. Leafminers are also occasionally found on tomato plant leaves and the infested leaves can be manually removed (Albajes, 1999).

The garden cucumber belongs to the Cucurbitaceae family and has been cultivated for thousands of years. This vegetable is frost sensitive and requires heat, more so than other vegetable species. It will grow poorly if kept in shady conditions. Due to its climbing nature, cucumber plants are often staked for support. These plants are typically monoecious, meaning male and female flowers grow on separate plants, however dioecious varieties have been bred. Female flowers develop into the popular cylindrical fruit which can come to be as long as 60 centimeters, with an average diameter of 10 cm (Encyclopedia Britannica, 1993). These herbacious vine plants, grow best on moist, well-drained soil that is both rich in organic matter and slightly alkaline (Burnham, 2013). In terms of nutrients, a ratio of 100:13:75:9:9 for nitrogen, phosphorus, potassium, calcium and magnesium has been found to be optimal. Nitrate is best due to the cucumber plants high sensitivity to ammonium as a source of nitrogen (Ingestad, 1973).

Swiss Chard, also known as leaf beet or spinach beet belongs to the Chenopodiaceae family. This leafy vegetable is similar to the beet however it lacks the fleshy root. Both the leaves and stalk can be consumed and both are high in nutrients. The wild form of swiss chard originated from southern Asia, and the Mediterranean, yet today the majority of its commercial production takes place in South Africa, Italy and California (Hemy, 1984). Swiss chard thrives in temperatures between 7-24 C (Pierce, 1987). Temperatures that significantly surpass this range cause reduced leaf size and wilting (Pierce, 1987). With a moderate deep root system, swiss chard requires consistent irrigation to prevent the medium from becoming more than 50% depleted in moisture (Hemy, 1984). Moisture should be kept relatively stable as large fluctuations cause leaves to become tough and growth rates to slow (Hemy, 1984). Nitrogen is the key element in fertilizer mixes in terms of its effect on plant growth. Finally swiss chard can be harvested when leaves are approximately 10 to 12.5 centimeters long. This typically takes 2 mo, if plants are propagated from seeds (Department of Agriculture, Forestry and Fisheries of South Africa, 2015).

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Sweet peppers as well as chilli peppers belong to the Solanaceae family and do best in soil with a high organic matter content. Similarly to cucumbers, these vegetables are easily damaged by frost and thus do best in warm climates. In tropical conditions, the rainy seasons can prove to be detrimental to these plants as heavy rain causes fruit rot. Excessive heat can also be an issue in tropical climates such as the climate found in Barbados. Optimal temperature for peppers is found to be between 16 and 26 C, with temperatures higher than 30 C being responsible for harmful conditions such as reduced fruit set, and dropping of buds, flowers and fruits (Yisa et al., 2013). Anthropods and nematodes are associated with reduced yields. Mildew caused by Leveillula taurica is common in tropical greenhouse operations and can only be tackled with the use of fungicides. Viruses are extremely prevalent amongst pepper plants and cause a long list of symptoms ranging from leaf mosaic, to leaf curling, plant distortion and plant growth stunting. Adding to the threats faced by sweet peppers and chilli peppers are viruses, namely cucumber mosaiv virus (CMV) and thrip-transmitted tomato spotted wilt virus (TSWV) which typically infect tomato and cucumber plants. This is especially relevant in the context of the Bellairs NVAC greenhouse seeing as these species have all been planted adjacent to one another in a constricted 9 X 3.3 m (30 x 10 ft) space (Yisa et al.,2013).

Water at Bellairs

During our plant growing trials, there were many days where insufficient amounts of rainwater from the Bellairs rainwater catchment system was available to supply water for fertigation. Therefore, groundwater from the water pipe in front of Bellairs had to be put into the irrigation tank in the greenhouse to provide amounts suitable for dissolving the hydroponic solution to fertigate the plants. While there were days of ample rainfall during the day or overnight, the rain catchment system could not catch a large amount of this rainfall. We advise that Bellairs improves their rain catchment system. This could be done by placing more gutters on the Brace building or even adding a gutter system on other buildings at Bellairs. For instance, gutters could be placed on top of the sheds located in front of the Brace building and be connected to the rain catchment tank for collection. Gutters on the outside perimeter of the greenhouse are installed to catch more rainwater that will be fed to the greenhouse water tank used for fertigation (refer to figure 14). A downspout will be connected to the gutter to enable the water to flow down into PVC plastic piping back to the greenhouse water tank. A sump pump will be used to pump this water from the gutter to the water tank. With improvements made to Bellairs’s rainwater catchment system and the construction of our rainwater catchment gutters onto the greenhouse, we hope that Bellairs will provide a more sustainable and efficient system to supply water for the greenhouse.

Pests, Diseases and Plant Health

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Pests and disease have been one of the most damaging aspects in vegetable production since the beginning of agriculture. Though greenhouses have been paramount in reducing pest infestation, they do not ensure the utter annihilation of plant pests and diseases. In fact, if contamination arises, greenhouses create a sheltered and optimal environment for infestation. Bacteria, fungus and viruses represent three categories of biotic disease organisms. Bacteria are microorganisms which reproduce by cell division. The minuscule organisms enter plants through natural openings such as through the stomata or through wounds. Bacteria can be transmitted from one plant to the next via irrigation or through physical contact and tool contamination. Less commonly, some bacterial species are transmitted via an insect vector. Viruses are made up of nucleic acids and a protein coat and generally require a host to survive. Plant viruses are successful in spreading into all the plant components including leaves, stems, seeds and flowers. Viruses are generally spread via anthropoid vectors such as aphids, leafhoppers, whiteflies, thrips, beetles and spider mites. Other viruses are carried in soil borne nematodes, or directly in soil. These viruses will be disregarded for the purpose of this project as here the medium used is a soil-less medium. This is, of course, advantageous in avoiding soil borne pathogens. Viruses can also be present in water, causing their spread to be extensive as a result of irrigation systems. Fungi are multicellular by nature and reproduce via spores. Fungi can penetrate plant tissues or enter via existing openings such as wounds. There is a wide variety of fungi, each occupying different niches on plants. Some require plants to be living while others thrive on decaying organic matter. Fungi have evolved to be host specific in many cases. The most common modes of transmission are air or water. As for abiotic disease, these come about under the influence of environmental stresses. Large fluctuations in temperature are an example of environmental stress which increases the risk of plant mold and mildew. Plant spacing is also a crucial element in reducing the risk of disease through disruption of favorable microclimates. Lastly, fertilizer ratios play a major role in increasing or reducing the incidence of pests and disease. Excessive nitrogen makes plants susceptible to aphid and leafminer infestations. Therefore nitrogen and phosphorus ratios should be carefully monitored. Calcium availability leads to structurally stronger plants and reduces pathogen penetration of plants (Koike et al., 2006).

The majority of plants were planted on June 14th via seeds which had been planted in peat pods earlier in June. In addition to these a number of store bought plants were planted. On June 14th, nine tomato plants we're transplanted in the first row, these had been kept for 2 weeks in a shaded area after we had propagated seeds within peat pods. Seven cherry tomato plants which had been store bought with initial growth of approximately 10 cm we’re also transplanted in the first row. In the second row, six swiss chard plants we're transplanted after they had been propagated via seeds in peat pods and kept in a shaded area for 3 weeks, similarly to the tomato plants. In the second row, nine sweet pepper plants which had also been propagated in peat pods via seeds we're transplanted. For the purpose of the sweet pepper plants, we also transplanted six store bought plants in total. These of course achieved greater heights as their initial height, when planted, was superior to the initial height of the seed propagated sweet pepper plants. Finally, in

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the third row, six peat pods containing seed propagated kale were transplanted. However these kale plants failed to grow and remained stunted at the average height of 9 cm. Thus, we removed the kale plants and replaced them with store bought cucumber plants. These, contrary to the kale plants, grew at an impressive pace. As of now there are a few spaces without any plants. This is due to a constraint in irrigation equipment. The individual emitters used for the drip irrigation at each plant site are not sold here in Barbados.. The plants, overall, are growing at a steady pace, as table 3 demonstrates. A key concern has to do with plant health and recent disease symptoms. Specifically, the pepper plants (1-19,1-20,1-21), are being heavily infested by ants. While this has not shown to significantly affect plant growth, the leaves are wilted on these plants and the single pepper grown by plant 1-21, was stunted in development. Ants can mean a number of things in the context of vegetable production. Ants can be advantageous as they predate upon other insects. But they can also be harmful in that they secrete folic acid which causes physical injury to the plants tissues. Some horticulturalists will resort to excessive rinsing to remove the ants, however this should be avoided as it can induce other problems such as blossom drop. Ants can also be attracted to vegetable plants due to secretions left behind by aphids. Aphids produce a white substance termed “Honey Dew” upon which ants feed. In this case the ants are not a major threat but the presence of aphids is alarming and requires rapid action (Garden Web, 2011). As well, the cucumber plants (3-1,3-2,3-3,3-4,3-5,3-6) have necrotic spots on their leaves with visible caterpillars causing the damage. Manual removal of these caterpillars has been the sole treatment employed at this point, however we are planning on acting to eradicate these harmful caterpillars. Options include BT (Bacillus thuringiensis), or hot pepper spray. Currently, a diluted solution of Vermitec 18EC insecticide is being used to control the white fly problem, and we have seen an improvement in the conditions of the peppers.

Fertilizer mix

To enable optimal plant growth for our plants, soluble hydroponic nutrient was added to the greenhouse water tank for irrigation. Referring to Figure 11 for specific ingredients, the hydroponic nutrient consisted of mostly nitrogen (6 %), phosphorus (as phosphoric acid – 12 %), potassium (as potash – 3.25 %), magnesium (3.25 %), and small amounts of trace nutrients. Nitrogen, phosphorus and potassium are important nutrients that promote stronger growth of plant foliage, and help root and flower growth and development, respectively (Clean Air Gardening, n.d.). In addition to promotion of flowering, potassium regulates water and nutrient intake and absorption (MacDonald, 2016). Besides these major components of the hydroponic solution, two macronutrients were also added to the irrigation tank: magnesium (as magnesium sulphate) and calcium (as calcium nitrate) (refer to Figures 12 and 13). Magnesium is a critical additive to Barbados soils and in hydroponics; it is needed to synthesize chlorophyll and for

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photosynthesis (Promix, 2015). Calcium is critical in cell walls and as a signaling molecule for important cell activities.

3. Objectives / Working Plan:

General Objective:

1. To finish building the greenhouse. 2. Test the NVAC’s properties and overall utility in a tropical environment.3. Grow the first hydroponic crop in this new NVAC structure.

Specific Objectives:

1a. The first goal of our project was to finish the construction of the greenhouse. To be specific, this goal consisted of completing the building of the roof. The building of the roof was for the purpose of encapsulating the optimal, cooler air needed (cooled by the installed misting system) for our plants to grow. Furthermore, the roof protects the plants from threats such as pests, wind, and heavy rainfall damage. Construction of the greenhouse roof was completed on Monday, June 6th, 2016. Wiggle wire track was screwed to the end of all three roofs using metal roofing screws. It has previously been installed around the base of the roof and along the vertical supports at the end of the greenhouse. The plastic was measured and cut to appropriate lengths. Roof 3, the top roof, was installed first followed by roof two (middle) and one (lowest). After the plastic was laid across the roof in the proper position, the wiggle wire was worked into the track along the top of the roofs, locking the plastic into place. Once this was done for roof 1 and 2, the wiggle wire at the end was attached with more wiggle wire. The extra plastic was trimmed to ensure a neat and finished look. Minor construction jobs after the completion of the roof were undergone also to improve the greenhouse. Supports were added between the roofs to solidify the structure. The supports are metal fence top poles and were attached using a variety of metal fence connector pieces. Once the construction was complete, rubber sheeting, enforced with nylon mesh, was placed over any metal pieces that threatened to rip the plastic sheeting for the roof. A metal fence was also added along the nylon walls of the greenhouse for security measures. In order to improve the greenhouses water efficiency, guttering was placed along the top of the outside walls of the greenhouse for the purpose of supplying more efficient rainwater catchment for fertigation (figure 14).

1b. The second goal consisted of connecting a PVC pipeline from the Bellairs roof rainwater catchment tank (Tuff Tank, Rotoplastics LTD., Barbados) to the greenhouse to supply water for the irrigation and the misting line. In order for hydroponics to be a sustainable way of growing

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plants, water needs to be supplied to allow fertigation (fertilizer and irrigation) for plant growth. Moreover, the rainwater provides cooling of the plants and the surrounding air in the greenhouse through the misting system. This goal was completed on Monday, June 13th, 2016. There are two 1,000-gallon water tanks (Tuff Tank, Rotoplastics LTD., Barbados) collecting rainwater from the roof of the Brace building, on the Bellairs campus. The constructed PVC pipeline was tapped from these two tanks to the greenhouse to enable water transport for irrigation from these tanks to the greenhouse. As the rainwater from the 1,000-gallon water tanks reaches the greenhouse, the PVC pipeline was then tapped into a 200-gallon tank (Tuff Tank, Rotoplastics LTD., Barbados) inside the greenhouse that acts as the mixing tank for the hydroponic fertilizer used to fertigate the plants. PVC pipelines were also constructed from the growing beds to the blue runoff gutter tank and back to the fertigation tank (figure 15 and 16) to allow the catchment of plant water effluent and greenhouse runoff water from rainfall. A sub pump (Flotec 1/6hp, 120V submersible pump) was placed in the blue greenhouse runoff and effluent tank to enable the water to travel back to the 200-gallon fertigation tank (figure 4).

1c. The third goal was to provide electricity to the greenhouse The energy source that supplies Bellairs with electricity is supplemented from the solar panels located on the roof of the Brace building. This goal was completed on Tuesday, June 14th, 2016. This was done for the purpose of providing electrical power to the water pumps, the irrigation control system in the greenhouse, and the data logger. To power the pumps, we tapped into the electricity from a shed in the Bellairs yard. A 4-wire cable was used to run two 110-volt lines into the greenhouse. Two 15-amp breakers were installed in the existing breaker box in the shed. A breaker box with two breakers was installed in the greenhouse (refer to figure 17). From here we established 110 V and 220 V electrical outlets in the greenhouse. These were used to power the pumps (1. 230V Pentax Water Pump Model: CAM75/00, Pentax Water Pumps, Italy – Irrigation line; 2. 115V/230V Hydropro Water Systems Tank Model: C48J2DA23A2, Goulds Water Technology, U.S.A – Water from the Brace building to the greenhouse; 3. Arizonamist Booster Pump, Orbit, U.S.A – Misting line; 4. Flotec 1/6hp, 120V submersible pump – greenhouse runoff and effluent pump), computer and data logger (HOBO Remote Modeling System, U30 Station, U.S.A) and the automated irrigation system (Toro Evolution, Toro, U.S.A) in the greenhouse. All 4 pumps supplied with electricity were used for various required purposes to successfully create the NVAC greenhouse. The largest (115V/230V Hydropro Water Systems Tank Model: C48J2DA23A2, Goulds Water Technology, U.S.A) brings water from the 1,000-gallon tank into the greenhouse, which then feeds the 200-gallon tank, misting line and hose. To achieve appropriate high pressure 165 PSI, water travels though another pump (Arizonamist Booster Pump, Orbit, U.S.A) which sends it up to the misting line. A sump pump (Flotec 1/6hp, 120V submersible pump – greenhouse runoff and effluent pump) was used to move collected rainfall and hydroponic effluent back to the 200-gallon tank (Tuff Tank, Rotoplastics LTD., Barbados). There is also a pump feeding water from the 200-gallon tank into the hydroponic irrigation line (230V Pentax Water Pump Model: CAM75/00, Pentax Water Pumps, Italy).

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2a. Plant growth was initiated in the NVAC greenhouse. A number of plant species were grown hydroponically and will be used to supply food to Bellairs kitchens for the first time. These crops include tomato plants (Solanum lycopersicum ‘Heatmaster’), cherry tomatoes (Solanum lycopersicum var. cerasiforme), cucumber plants (Cucumis sativus cv. unknown), swiss chard plants (Beta vulgaris sub. Vulgaris cv. unknown), sweet pepper plants (Capsicum annuum sub. annuum ‘King Arthur’), and chili peppers (Capsicum annuum). In order to do so, coconut (coir) growing bags (Coconut Coir Growbags, Cocogreen, U.K.) were used to place our germinated seeds in. The seeds were then supplied a hydroponic solution (1. Calcium Nitrate, ECFCO, Barbados; 2. Magnesium Sulphate, ECFCO, Barbados; 3. Soluble Hydroponic Nutrient, Verti-Gro, Florida, U.S.A) from the drip irrigation line directly from the greenhouse water tank. Strings were tied on the grow bags to support wires running lengthwise along the greenhouse and used to support the plants as they grow (figure 17). The hydroponic system is automated with a computer system (Toro Evolution, Toro, U.S.A.) that has a schedule for both the mist line and fertigation system. These are connected to the piping system via solenoid valves. The nutrient solution was prepared and planting was completed on Tuesday, June 14th, 2016.

2b. Testing the greenhouse involves collecting temperature, relative humidity, and solar radiation data using Onset Corporation data loggers for the reason of keeping track, finding, and maintaining appropriate levels of each environmental parameter to promote the growth of the plant species mentioned above in objective 2a. Sensors were placed in the appropriate spots (refer to figure 20) to record the air temperature, relative humidity, and solar radiation levels in the greenhouse that plants are being subjected to. Air temperature and relative humidity sensors were placed in various locations at a height of 1.5 m. This is to ensure that these parameters are measured overtop of the plant canopy as suggested by the American Society of Agricultural and Biological Engineers (McCartney, 2015). The solar radiation sensor was placed at a similar height of 1.5 m in the center of the greenhouse where shade is minimal to measure sunlight intensity (Kri’zek et al., 2012). Data using the HOBOware (HOBO Remote Modeling System, U30 Station, U.S.A) was collected on days with and without the misting system operating to test the overall effect the misting line has on the temperature and relative humidity in the greenhouse. Referring to our timeline, data collection started on Tuesday, July 5th, 2016 and was continuously recorded from this day until Monday, August 1st, 2016.

3a. A manual has been written for the purpose of continuing production of the greenhouse after we have left Barbados. The following manual includes the important requirements in order to help maintain crop productivity in the greenhouse. These include adding fertilizer to the 200-gallon irrigation water tank (Tuff Tank, Rotoplastics LTD., Barbados) for the hydroponic

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system, refilling the irrigation tank with water from the 1,000-gallon rainwater catchment tanks (Tuff Tank, Rotoplastics LTD., Barbados) at the Brace building through the PVC pipeline, and providing general maintenance on the automated irrigation system (Toro Evolution, Toro, U.S.A.). We havc been working with Bellairs groundskeepers to ensure they are comfortable working with all systems within the greenhouse.

4. Calculations

A) Minimum start-up power sequence for pump

Pump 1: Water from rainwater catchment to greenhouse

½ HP, 4 Amps, 220 Volts

Running power:

P=VI

P=220 V ×2 A

P=¿880 Watts

Start-up power:

Pstart=Prunning × 4.8

Pstart=880 W × 4.8

Pstart=¿4224 Watts

Pump 2: Increase pressure to misting line

1 Amp, 110 V, 60 Hz

Running power:

P=VI

P=110 V × 1 A

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P=¿110 Watts

Start-up power:


Pstart=110W × 4.8

Pstart=¿528 Watts

Pump 3: Hydroponic System

0.8 HP, 3.7 Amps, 220 V

Running power:

P=VI

P=220 V ×3.7 A

P=¿814 Watts

Start-up power:


Pstart=814 W × 4.8

Pstart=¿3907.2 Watts

Table 1: The start-up sequence of pumps and total power on the line as each is turned on

Starting Pump

Run Power(W)

Start-up Power(W)

Power on Line before Start-up(W)

Total Power on Line during start-up (W)

Pump 1 880.0 4224 0 4224Pump 3 814.0 3907 880.0 4787Pump 2 110.0 522.0 1694 2222All at running power

1804

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Turning on the pumps in the order 1-3-2 will reduce stress on the electrical consumption of Bellairs. When motors turn on, they need to use more energy than their running power. So, by following this order, the motors will start from highest start-up power to lowest and only be at their start-up power individually.

B) Total daily water usage in greenhouse

Hydroponic system

30 Nozzles have flow rates of 4 L/h

30 X 4 L/h X 1 hour/60 minutes = 2 L/minute

27 Nozzles have flow rates of 2 L/h

27 X 2 L/h X 1 hour/60 minutes = 1 L/minute

While hydroponic system is running it utilizes 3 L/minute

The system runs for 7 minutes, 4 times/day

3 L/minute X 7 Minute X 4/day = 84 L/day for hydroponics

Each nozzle is placed in one spot of the grow bag, and can support the growth of one plant, for 57 plants total.

See figure 23 for layout of plants in hydroponic system.

Misting system

The misting system is automated, and will be running when the temperature exceeds 30 C. In Barbados, this is usually between 8:30 am and 5 pm, therefore for 8.5 hours/day. The exact length of run time will be recorded by the computer, as the exact length of time will vary daily.

1.89 L/hour X 7 nozzles X 8.5 hours/day = 112.5 L/day

Total daily water usage:

84 L/day + 112.5 L/day = 196.5 L/day

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**This is the maximum water use; currently the flow is lower as not all hydroponic emitters are in use**

C) Average temperature decrease at canopy level due to misting system sample calculation

**this calculation was done using Microsoft Excel, this calculation shows the procedure and obtained values

Average=

avg canopy temp. of day with no misting system – avg canopy temp. of day with misting system

Average difference between the average temperatures when the misting system is off

Average difference between the average temperatures when the misting system is on

-0.474 C 0.538 C

Average difference between misting system being on and off =

0.538 C – (-0.474 C) = 1.012 C

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5. Timeline:

Monday, May 23rd, 2016:

Put up scaffolding – Completed

Monday, May 23rd, 2016 – Monday June 6th, 2016

Finish constructing the roof – Completed:

o Placing tracks on the three roofs

o Wiggle wiring the 6-mil clear polyethylene roof sheeting covering to the tracks on the three roofs

o Drilling support pipes for the roof

Tuesday, June 7th, 2016:

Put up misting line and attach to the roof - Completed

Buy seeds for planting - Swiss chard, kale, sweet pepper, cherry tomatoes, tomatoes - Completed

Buy hydroponic nutrients - water dissolvable N:P:K, Mg, and Ca fertilizer (refer to Figure 5) - Completed

Buy germinating pods to place seeds in to enable germinating - Completed

Wednesday, June 8th, 2016:

Place seeds in germinating pods and start propagation - Completed:

o Place pods in water to soak up water and enlarge

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o Place seeds in germinating pods

o Put seeds in dark place to germinate for next week

Monday, June 13th, 2016:

Finish constructing PVC water line - Completed

o Dig out pipeline path towards the greenhouse

o Placed PVC pipes on the path, piece pipe pieces together and connect to 200-gallon water tank and water pumps for irrigation and misting line in the greenhouse

o Construct PVC water line from 1,000-gallon rainwater catchment tank to the greenhouse. Connect to greenhouse water tank and the pumps

Buy electrical wire (4 wire electrical cable), plug heads (one 110 volt and one 220 volt), breaker box, breakers to construct electrical system to power water pumps. Needed to bring water from the Bellairs rainwater catchment tank to the water tank in the greenhouse for irrigation and misting line - Completed


Put together the electrical to power the water pumps and irrigation schedule system - Completed

o Connect 4 wire electrical cable from the breaker box in the Bellairs shed to the breaker box constructed in the greenhouse

o Attach the greenhouse end to plug heads to plug into the outlet in the greenhouse

Construct growing bag support beds to place growing bags on for seed propagation (refer to figure 3 - picture of construction) - Completed

o 1) Use pickaxe to slant the surface in order to allow the water to flow to the end drain of the plastic growing bed holders

o 2) Placed cinderblocks on the adjusted surface and placed 12 foot 2x4 wood on top to place plastic growing bag holders and growing bags on for seed propagation (refer to figure 3)

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o 3) Attach a wire to each end of the greenhouse. Used for holding the plastic growing bag holders together with the growing bags in them and to provide plant support for the plants as they grow (refer to figure 3)

Begin planting seeds in the coir growing beds - Completed:

o Take the coir growing bags and place in a water container to soak up water

o Place growing bags in the plastic growing bag holders

o Place germinated seeds in growing pods in the coir growing bags. Planted 30 cm’s apart.

Construct irrigation line from the greenhouse water supply tank for the seeds in the growing bags - Completed:

o Attach an adaptor to PVC pipe from the greenhouse water tank to the irrigation line

Supply irrigation water in the greenhouse water tanks with N:P:K, Mg, and Ca dissolvable nutrients - Completed

Start plant growing - Completed


Complete proposal for our project - Completed

Tuesday, June 21st, 2016:

Construct two more growing bed rows (same methods used before on June 14th) – Completed

Plant more seeds in two other growing beds – Completed

Finish placing more plant strings – Completed

Put up aluminet shade netting to shade the plants in the greenhouse – Completed

Sunday, June 26th, 2016:

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Re-handing in our revised proposal (15%) – Completed


Set up HOBOware data recording system to track temperature, relative humidity, and sunlight radiation while plants grow. Used by setting up sensors – Completed


Placing gutter bottoms of inside roof – Completed

Monday June 27th - Monday, August 15th, 2016:

Collect temperature, relative humidity, and sunlight radiation from software - Completed

Monday, July 11th, 2016 – Monday, July 18th, 2016:

Work on progress report – Completed

Monday, July 18th, 2016:

Hand in progress report (15%) – Completed

Monday, July 25th – 26th, 2016: - Completed

Worked on completing the guttering on the greenhouse for water catchment Constructed PVC pipeline to the grow bags to catch plant effluent Connected both the guttering and PVC effluent pipeline to a blue plastic tank used to

catch both plant effluent and greenhouse rainwater

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Constructed PVC pipeline from the blue tank to the 200-gallon irrigation tank (Tuff Tank, Rotoplastics LTD., Barbados)

Placed sub pump (Flotec 1/6hp, 120V submersible pump) in the blue tank to bring water from the blue tank to the irrigation tank

Monday, August 1st, 2016:

Stopped temperature, relative humidity and solar radiation data recording with HOBOware software – Completed

Monday, August 8th, 2016 – Monday, August 15th, 2016

Work on final report

Monday, August 15th, 2016:

Hand in final written report (25%): - Completed

o Summary of project (10%)

o Advertisement (10%)

Friday, August 19th, 2016:

Do final group presentation for project (25%):

o Power point and video

6. Materials:

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6-mil clear polyethylene roof sheeting DeWalt power drill 6ft ladder 8ft ladder 30 foot ladder 3/4” PVC piping 90 PVC piping pieces 45 PVC piping pieces 3/4” PVC 40 – Solv valves 1/4” female threaded PVC fittings Shovel Pickaxe Hammer Exacto-knife Cinderblocks Metal cutting saw Wood saw Wood 4x4 planks Aluminum wiggle wire tracking Wiggle wire 200-gallon water tank (Tuff Tank, Rotoplastics LTD., Barbados) 1,000-gallon water tank at the Brace building (Tuff Tank, Rotoplastics LTD., Barbados) 4 inch guttering 4 inch guttering fittings to fit gutters in place Seminis Hybrid Tomato seeds, variety: heatmaster Seminis Hybrid Sweet Pepper seeds, variety: King Arthur Swiss Chard seeds Chili pepper seedlings Sweet pepper seedlings Cherry Tomato seedlings Water pumps:

1. 230V Pentax Water Pump Model: CAM75/00, Pentax Water Pumps, Italy – Irrigation line

2. 115V/230V Hydropro Water Systems Tank Model: C48J2DA23A2, Goulds Water Technology, U.S.A – Brought water from the Brace building to the greenhouse

3. Arizonamist Booster Pump, Orbit, U.S.A – Misting line4. Flotec 1/6hp, 120V submersible pump – Greenhouse runoff and effluent

pump 30 4 litres/hour nozzels

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27 2 litres/hour nozzels 1” aluminum piping Aluminum pipe clamps Aluminum piping caps Vertimec 18EC Insecticide 1 litre spray bottle Aluminet shade cloth Growing string Coconut coir grow bags (Coconut Coir Growbag, Cocogreen, U.K.) Black plastic grow bag holders Drip irrigation spouts 9.525mm outer diameter and 1.905mm wall thickness black nylon tubing for the

irrigation and misting lines. Two filtration units, a Netafim 100-micrometer (μm) filtration grade filter (Amiad Water

232 Systems Ltd. Israel) 20-μm filtration grade filter (Culligan Water, Rosemont, IL). 1/8” polyethylene micro tubing (0.125” ID x 0.187” OD) used to connect the nozzels on

the irrigation line to the drip irrigation spouts Silicon glue 1-1/4” wood screws Aluminum spring washers Steel washers Steel braided wire to hold the aluminet shade cloth Blue effluent and greenhouse water catchment tank Seed growing pods and trays Steel clips to hold polyethylene and aluminet shade cloth in place on the greenhouse Green cushion sheeting put around the screws and bolts on the roof to prevent them from

ripping through the polyethylene roofing Stanley 18” leveller Plastic clips to clip plants to growing strings 1/2” galvanized roofing screws Steel u-bolts 3/8” aluminum nuts Steel hex bolts 1/4”, 10mm, and 1/2” wrenches Stanley vice grips 3/4” wood boring bit Plastic zip ties Whitlam Weatherproof 1 Step Low VOC Medium Blue PVC Cement Whitlam Low VOC Clear Cleaner

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Psi pressure gauge Weatherproof breaker box 2 15-amp breakers 110V and 220V electrical outlets 4-wire cable White teflon tape 2 15-amp 3 wire grounding electrical plug heads 2 weatherproof white electrical outlets 30 foot water hose Grow bag trays Automated irrigation system (Toro Evolution, Toro, U.S.A.) HOBOware data recording software (HOBO Remote Modeling System, U30 Station,

U.S.A)

Note: Everything completed on the following dates and for future dates were completed together as a team. No splitting up of work was done and will not be done for the rest of the project.

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7. Data and Analysis:

0:01 1:04 2:07 3:10 4:13 5:16 6:19 7:22 8:25 9:28 10:3111:34 12:44 13:47 14:50 15:5316:56 17:59 19:0220:05 21:08 22:11 23:1422

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26

28

30

32

34

36

38

40

Average 24 Hour Temperature At Canopy, Gutter, And Misting Heights With No Misting System Active On July 7, 2016

Average Canopy Temperature Average Temperature at Gutter Height Average Temperature at Misting Line HeightTime

Tem

pera

ture

(◦C

)

Graph 1 - Average 24-hour data of the greenhouse temperature at the canopy, gutter and misting line level on July 7 th, 2016 with no

misting system active. A large drop in temperature at approximately 3:30 can be noticed due to a rainfall event during the day.


0:01 1:31 3:01 4:31 6:01 7:31 9:01 10:3112:0813:3815:0816:3818:0819:3821:0822:3835

45

55

65

75

85

95

Average 24 Hour Relative Humidity At Canopy, Gutter,And Misting Heights on July 7th, 2016 Without Misting System Active

Average RH at Canopy LevelAverage RH at Gutter HeightAverage RH at Misting Line Height

Time

Rel

ativ

e H

umid

idty

(%)

Graph 2 - Average 24-hour data of relative humidity (%) in the greenhouse on July 7th, 2016 without activation of the misting system.

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0:01 1:01 2:01 3:01 4:01 5:01 6:01 7:01 8:01 9:01 10:0111:0112:01 13:0114:0115:0116:01 17:0118:0119:0120:0121:01 22:0123:0122

24

26

28

30

32

34

36

38

40

Average 24 Hour Temperature At Canopy, Gutter, and Misting Level On July 14th, 2016 With Misting System Active

Average Temp Canopy Average Temp Gutter Level Average Temp Misting Level

Time (Hrs)

Tem

pera

ture

(Cel

sius)

Graph 3- Average 24 hour temperature data of the greenhouse on July 14th, 2016 at canopy, gutter, and misting height levels. The two

vertical lines at approximately 10 am to 2 pm represent the time at which the misting system was turned on and off. The misting system

turned on at 10am and then turned off at 2 pm. The misting system was constantly spraying between these times.

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0:01 1:04 2:07 3:10 4:13 5:16 6:19 7:22 8:25 9:28 10:31 11:34 12:37 13:40 14:43 15:46 16:49 17:52 18:55 19:58 21:01 22:04 23:0735

45

55

65

75

85

95

Average 24 Hour Relative Humidity At Canopy, Gutter, And Misting Levels On July 14, 2016 With Misting System Active

Average RH Canopy Level Average RH Gutter Level Average RH Misting Level

Time (Hrs)

Rel

ativ

e H

umid

ity (%

)

Graph 4 - Average 24 hour data of relative humidity on July 14th, 2016 for canopy, gutter, and misting height levels. The two vertical lines

at approximately 10 am to 2 pm represent the time at which the misting system was turned on and off. The misting system turned on at 10

am and then turns off at 2 pm. The misting system was constantly spraying between these times.

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0:01 1:01 2:01 3:01 4:01 5:01 6:01 7:01 8:01 9:01 10:0111:0112:0813:0814:0815:0816:0817:0818:0819:0820:0821:0822:0823:0822

24

26

28

30

32

34

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Average 24 Hour Temperature With Misting System Active Vs. When Misting System Is Not Active At The Canopy Height Level

Average temp at canopy with misting system Average temp at canopy no misting

Time (hrs)

Tem

pera

ture

(◦C

)

Graph 5 - Average 24 hour temperature with misting system active (blue line) vs. when the misting system is not active (orange line) at the

canopy height level. The two vertical lines at approximately 10 am to 2 pm represent the time at which the misting system was turned on

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and off (relevant to blue line only – misting). The misting system turned on at 10 am and then turned off at 2 pm. The misting system was

constantly spraying between these times.

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0:01 1:01 2:01 3:01 4:01 5:01 6:01 7:01 8:01 9:01 10:01 11:01 12:01 13:01 14:01 15:01 16:01 17:01 18:01 19:01 20:01 21:01 22:01 23:0135

45

55

65

75

85

95

Average 24 Hour Relative Humidity With Misting System Active Vs. When Misting System Is Not Active At The Canopy Height Level

Average RH of canopy, with misting system Avg RH canopy no mist

Time (hrs)

Rel

ativ

e H

umid

ity (%

)

Graph 6 - Average 24 hour relative humidity with misting system active (orange line) vs. when the misting system is not active (blue line)

at the canopy height level. The two vertical lines at approximately 10 am to 2 pm represent the time at which the misting system was

turned on and off (relevant to orange line only – misting). The misting system turned on at 10 am and then turned off at 2 pm. The

misting system was constantly spraying between these times.

40


0:01 1:04 2:07 3:10 4:13 5:16 6:19 7:22 8:25 9:28 10:31 11:34 12:44 13:47 14:50 15:53 16:56 17:59 19:02 20:05 21:08 22:11 23:1435

45

55

65

75

85

95

Average 24 Hour Relative Humidity With Misting System Active Vs. When Misting System Is Not Active At The Gutter Height Level

Average RH at gutter height, with mising system Average Gutter RH, no mist

Time (hrs)

Rel

ativ

e H

umid

ity (%

)

Graph 7 - Average 24 hour relative humidity with misting system active (blue line) vs. when the misting system is not active (orange line)

at the gutter height level. The two vertical lines at approximately 10 am to 2 pm represent the time at which the misting system was

41


turned on and off (relevant to blue line only – misting). The misting system turned on at 10 am and then turned off at 2 pm. The misting

system was constantly spraying between these times.

42


0:01 1:01 2:01 3:01 4:01 5:01 6:01 7:01 8:01 9:01 10:0111:0112:0813:0814:0815:0816:0817:0818:0819:0820:0821:0822:0823:0835

45

55

65

75

85

95

Average 24 Hour Relative Humidity With Misting System Active Vs. When Misting Sys-tem Is Not Active At The Misting Height Level

Average RH misting height, with misting system Average Misting Heigh, no mist

Time (hrs)

Rel

ativ

e H

umid

ity (%

)

Graph 8 - Average 24-hour relative humidity with misting system active (green line) vs. when the misting system is not active (grey line) at

the gutter height level. The two vertical lines at approximately 10 am to 2 pm represent the time at which the misting system was turned

43


on and off (relevant to green line only – misting). The misting system turned on at 10 am and then turned off at 2 pm. The misting system

was constantly spraying between these times.

44


0:01 1:04 2:07 3:10 4:13 5:16 6:19 7:22 8:25 9:28 10:3111:3412:4413:4714:5015:5316:5617:5919:0220:0521:0822:1123:1422

24

26

28

30

32

34

36

38

40

Average 24 Hour Temperature With Misting System Active Vs. When Misting Sys-tem Is Not Active At The Gutter Height Level

Average temp at gitter height with misting system Average temp at gutter height, no mist

Time (hrs)

Tem

pera

ture

(◦C

)

Graph 9 - Average 24 hour relative humidity with misting system active (orange line) vs. when the misting system is not active (blue line)

at the gutter height level. The two vertical lines at approximately 10 am to 2 pm represent the time at which the misting system was

turned on and off (relevant to orange line only – misting). The misting system turned on at 10 am and then turned off at 2 pm. The

misting system was constantly spraying between these times.

45


0:01 1:04 2:07 3:10 4:13 5:16 6:19 7:22 8:25 9:28 10:31 11:3412:44 13:47 14:5015:53 16:56 17:5919:02 20:0521:08 22:11 23:1422

24

26

28

30

32

34

36

38

40

Average 24 Hour Temperature With Misting System Active Vs. When Misting System Is Not Active At The Misting Height Level

Time (hrs)

Tem

pera

ture

(◦C

)

Graph 10 - Average 24 hour relative humidity with misting system active (grey line) vs. when the misting system is not active (blue line) at

the misting height level. The two vertical lines at approximately 10am to 2pm represent the time at which the misting system was turned

46


on and off (relevant to grey line only – misting). The misting system turned on at 10 am and then turned off at 2 pm. The misting system

was constantly spraying between these times.

0:01:27 2:13:26 4:25:27 6:37:27 8:49:26 11:01:2713:13:2715:25:2717:37:2719:49:2722:01:270

5

10

15

20

25

30

35

40

Temperature of canopy on July 30, 2016, with misting system on and off, compared to average temperature of days with no misting

July 30, mistinf system off

July 30, misting system on

Average temperature of days without misting

Time

Tem

pera

ture

(C)

Graph 11 – This examines the temperature at canopy height, comparing the temperature on July 30, when the misting system was on

between14:30 and 16:20 to the average temperature of many days without the misting system on. We see a sharp decrease in temperature

47


when the misting system turns on (red line), which brings the temperature in the greenhouse below the average. Note the rain event

between 12:00 and 13:00.

0:01:27 2:10:27 4:19:26 6:28:27 8:37:27 10:46:2712:55:2715:04:2717:13:2619:22:2721:31:2723:40:270

10

20

30

40

50

60

70

80

90

100

Relative humidity reading at canopylevel on July 30, 2016 compared to the average temperature of days without misting.

Misting system off, July 30

Misting system on, July 30

Average RH over several days, no mist -ing system

Time

Rela

tive

Hum

idid

ty (%

)

Graph 12 - This examines the relative at canopy height, comparing the temperature on July 30, when the misting system was on

between14:30 and 16:20 to the average temperature of many days without the misting system on. Although this evening was more humid

48


than average, we see an spike in the RH after the system comes on, leading us to believe this increase is caused by the mist. Note the rain

event between 12:00 and 13:00.

49


0:01:27 2:07:27 4:13:27 6:19:27 8:25:27 10:31:2712:37:2714:43:2716:49:2718:55:2721:01:2723:07:270

10

20

30

40

50

60

70

80

90

100

Relative humidity on July 31, 2016, with mist on and off compared to the average RH with no misting over several days

July 31, misting system off


Average RH at canopy over several days

Time

Rela

tive

Hum

idid

ty (%

)

Graph 13- This graph compared the temperature on July 31, 2016, during which the misting system turns on between 13:30 and 15:30.

We do not see drastic fluctuations in the pattern but we do see an increase in relative humidity while the misting system is running.

50


0:01:27 1:58:27 3:55:27 5:52:27 7:49:27 9:46:27 11:43:2713:40:2715:37:2717:34:2719:31:2721:28:2723:25:270

5

10

15

20

25

30

35

40

Temperature with misting system on and off on July 31, 2016, compared to the average temperature over several days, at canopy level.

July 31, misting system off


Average temperature over sev-eral days with no misting system

Time

Tem

pera

ture

(C)

51


Graph 14 - This graph compared the temperature on July 31, 2016, during which the misting system turns on between 13:30 and 15:30.

When the misting system is turned on we see a depression in the temperature of the greenhouse. This day is hotter than the average so

there is less impact from the misting system, this hypothesis is elaborated more late.

52

Discussion on Graphs:

Through-out all the graphs, many trends were noticed when looking at temperature and relative

humidity for each height level (canopy, gutter, and misting) according to the time of day and whether

misting was activated or not. Referring to all graphs showing average 24-hour temperature (refer to

graphs 1, 3, 5, 9, and 10) a trend was seen that temperature spiked up to its highest point at approximately

12 to 12:30 pm in the afternoon. This is explained by the fact that temperatures are generally the highest

in Barbados at around this time, hence producing higher temperature readings. When looking at all graphs

that represent average temperature, noticeable fluctuations in average temperature can be seen. This is

due to intermittent cloud cover and sudden increases in wind speed during the day. Interesting results

were also shown when comparing fluctuations in average greenhouse temperature when the misting line

was turned off during the full day (July 7th) and turned on from 10 am to 2 pm (July 14th) for each sensor

height (canopy, gutter, and misting) (refer to graphs 3, 9, 10). General trends indicated that the misting

line generated overall cooler temperatures than when it was not activated. Regarding graph 5, the

operating of the misting line achieved a noticeable decrease in greenhouse canopy level temperature

between 10 am to 2 pm of about 1.012 degrees Celsius when compared misting to non-misting data (refer

to calculation section part C). This therefore shows that the misting line is effective in cooling the

ambient air temperature within the greenhouse. Referring to the table of optimal growth temperature

ranges for each plant placed below (refer to table 1), the misting line allowed for temperatures to be

decreased at the canopy level within most of the crops’ optimal growth temperatures. For instance,

referring to graph 5, the highest average temperature read during misting was just below 34 degrees

Celsius at 11 am while the lowest average temperature read was about 30.5 degrees Celsius at about

12:30 pm. These temperatures and the temperatures that range between them (34C – 30.5C) seen on

graph 5 meet the optimal growing temperatures of every crop except for sweet pepper (~16C – 29 C)

(Howard, 2003) (refer to table 1). This being said, sweet pepper seems to be growing relatively well

within the greenhouse (refer to figure 18). It is noticed that average temperatures at the canopy level

without the misting line during the day (10 am to 2 pm) seem to be still within the optimal temperature

ranges of all the plants except sweet pepper also (max ~ 34.7C, min ~31.3 C – refer to graph 5).

Although this is true, the 1.012 degree decrease in ambient air temperature within the greenhouse at the

canopy level is likely to provide a more comfortable growing temperature for the plants and has made a

significant contribution to their current growing productivity better than if misting were not available. The

sensors at the misting height are recording higher temperatures than the canopy height due to the fact the

sensors are located in the heat that is being ventilated out the top of the roof (the heat that is rising out of

the greenhouse) (refer to graph 10 and 5). The canopy height leveled sensors are recording the lowest

temperatures because colder air sinks. Therefore, the colder air in the greenhouse surrounds these sensors


at the canopy level. Evapotranspiration from the plants is thought to be involved in cooling this air as

well. In all average temperature graphs, sudden drops in temperature can be noticed (refer to graphs 1, 3,

5, 9, 10). At these points, rain events occurred that cooled the air and caused the sensors to feel this

sudden temperature change.

In terms of relative humidity, a trend of increasing relative humidity is seen early in the morning

(~ 0:00 – 7:00) and from the evening into the night (~ 17:00 – 23:59). In the afternoon, relative humidity

is at its lowest. In contrast, as temperature decreases in the evening and during the night, the relative

humidity can be seen increasing (refer to graphs 2, 4, 6, 7, 8). Relative humidity is defined as the actual

vapor density of surrounding air divided by the saturation vapor density (the vapor density of the air if the

air was 100 % saturated). Water vapor in the air (actual vapor density) is defined as being reasonably

constant (Hole, n.d.). Therefore, as saturation vapor pressure decrease with decreasing temperature and

actual vapor density in the air is constant, the ratio is higher. As a result, the night and early morning

temperatures have higher humidity when the sun is not present to increase air temperature. Comparing the

graphs of relative humidity sensor height (canopy, gutter, and misting levels) with misting and non-

misting (refer to graphs 6, 7, and 8), each showed that relative humidity with misting activated from 10

am to 2 pm indicated higher relative humidity results than without misting. To clarify, adding the misting

caused higher moisture in the air and therefore, increased relative humidity. Comparing the relative

humidities at each sensor height, the air at the canopy level has a higher relative humidity than at both the

gutter and misting heights (refer to graphs 6, 7 and 8). This is the case due to plant respiration and

transpiration. As plant cells respire, carbon dioxide, water, and energy are produced. Transpiration from

the greenhouse plants released sufficient amounts of water into the air around the canopy level, resulting

in a higher relative humidity than the air at both the gutter and misting heights.

We see much more drastic effects on both relative humidity and temperature on July 30th, 2016,

as compared to data collected on July 31, 2016. The incident radiation measured in the greenhouse on

July 31 is almost double that of the 30th. We believe this may contribute to why we see less impact from

the misting system on the 31st. Although, this should contribute to higher rates of evaporation and

therefore more cooling in the greenhouse, the higher levels of radiation increase the temperature, making

it more challenging to achieve cooling. There still needs to be more research into this possible trend to

completely understand the cause(s) of this phenomenon.

55


Crop Type Optimal Temperature (C)Heatmaster Hybrid Tomato (Solanum

lycopersicum)~13C - 35C (Bonnie Plants, n.d.)

Cherry Tomatoes (Solanum lycopersicum cv. cerasiforme)

~16C - 35C (Heirloom Organics, n.d.)

Cucumber (Cucumis sativus cv. unknown) ~16C - 32C (Cornell University, 2006)Swiss Chard (Beta vulgaris sub. Vulgaris cv.

unknown)~ 4C - 35C

Optimal temp: 29C (Cornell University, 2006)Sweet Pepper (Capsicum annuum sub. annuum

‘King Arthur’)~16C - 29C (Howard, 2003)

Chili Peppers (Capsicum annuum) ~ 21C - 35C (Albert, 2016)Table 1 - List of optimal growth temperatures in degrees Celsius for each plant in the greenhouse.

Average light intensity while the misting system is working (E)July 30, 2016 76.2July 31, 2016 141.2Table 2: Light intensity during misting period

-

56


8. Appendix 1: Photos and Figures

Figure 1: Skeletal design of greenhouse, pre roof installation (6 mil clean ethylene sheeting)

Figure 2: Renting Scaffolding

57


Figure 3: Tubing for drip irrigations supplier

Figure 3: Plastic growing bag holder on cinder blocks, with drain

58


Figure 4: Pump and 200 gallon greenhouse water tank

Figure 5: Hydroponic fertilizer

59


Figure 6: Planting seedlings into grow bags

Figure 7: Picture of irrigation line and coir bags

60


Figure 8: Picture of seedling in grow bag

Figure 9: Picture of coir bags and supporting growing string

61


Figure 10: Putting up polyethylene sheeting for roof

Figure 11: Ingredients for dissolvable hydroponic nutrient.

62


Figure 12: Calcium nitrate dissolvable fertilizer added to greenhouse water tank.

Figure 13: Magnesium sulphate dissolvable fertilizer added to the greenhouse water tank.

63


Figure 14: Picture of outside guttering to catch rainwater from the greenhouse. Blue greenhouse rain catchment and plant effluent catchment tank is shown in this picture.

64


Figure 15: PVC pipeline connected to growing beds to catch plant effluent to put into the blue tank.

65


Figure 16: PVC pipeline connected from the blue plant effluent and greenhouse rainwater catchment tank to the 200-gallon fertigation tank.

66


Figure 17: Hanging wire supporting growing strings above.

67


Figure 18: Growing productivity of sweet peppers in the greenhouse.

68


Figure 14: Diagram of water system in greenhouse [Under construction, labels to be added]

69


Figure 15: Greenhouse Hydroponic System, diagram [Under construction, labels to be added]

70


Figure 16: Rain catchment system on the greenhouse, diagram [Under construction, labels to be added]

71


Figure 17: Misting system in greenhouse, diagram [Under construction, labels to be added]

72


Figure 18: Air currents in NVAC greenhouse

73


74


Figure 20: Simplified top view layout of the greenhouse, showing the locations of HOBOware

sensors

Figure 21: Simplified cross section of the greenhouse showing the location of HOBOware sensors. Canopy height is located 1.5 m from the ground.

75


Figure 22: Various naturally ventilated greenhouse roof designs. (shaded area shows open vents) (Boulard, et al. 1997)

76


figure 23: Layout of plans in hydroponic system in greenhouse

77


9. Appendix 2: Data

Table 3: Plant growth log

Background Information

Height (cm)

(July 5th)

Height (cm)

(July 12th)

Height (cm)

(July 18th)Tomato Plant 1-1

Planted from seed on June 14th.

19.5 cm 43.2 cm 61.0 cm

Tomato Plant 1-2


23 cm 49.5 cm 66.0 cm

Tomato Plant 1-3


25 cm 61.0 cm 73.7 cm

Tomato Plant 1-4


27.2 cm 52.1 cm 68.6 cm

Tomato Plant 1-5


22 cm 46.5 cm 66.0 cm

Tomato Plant 1-6


19.5 cm 41.0 cm 64.7 cm

Tomato Plant 1-7


26.5 cm 55.3 cm 81.3 cm

Plant 1-8 Plant killed upon planting June 14th.

- - -

Tomato Plant 1-9


5.0 cm 14.0 cm 33.0 cm

Cherry Tomato Plant 1-10

Planted from seedling on June 14th.

69.5 cm 81.0 cm 91.4 cm



62.0 cm 71.0 cm 85.1 cm



59.5 cm 68.0 cm 76.2 cm

Cherry Tomato Plant

Planted from seedling on

67.0 cm 76.5 cm 81.1 cm

78


1-13 June 14th.Cherry Tomato Plant 1-`14


62.7 cm 72.5 cm 83.1 cm



58.0 cm`` 69.5 cm 79.2 cm



10.3 cm 19.0 cm 40.6 cm

Plant 1-17 - - - -Plant 1-18 - - - -Sweet Pepper Plant 1-19


28.0 cm 34.0 cm 35.6 cm

Sweet Pepper Plant 1-20


32.0 cm 39.5 cm 40.6 cm



35.5 cm 42.0 cm 45.7 cm

Swiss chard Plant 2-1


14.2 cm 20.0 cm 25.4 cm



24.5 cm 27.0 cm 27.9 cm



12.0 cm 16.0 cm 22.9 cm



22.0 cm 24.0 cm 27.9 cm



23.4 cm 27.0 cm 29.2 cm



17.5 cm 21.5 cm 24.1 cm



8.2 cm 14.0 cm 22.9 cm



9.0 cm 14.0 cm 24.1 cm


Planted from seed on June

9.5 cm 16.5 cm 21.6 cm

79


14th.Sweet Pepper Plant 2-10


11.2 cm 32.0 cm 35.5 cm



9.5 cm 26.0 cm 27.9 cm



12.0 cm 18.0 cm 22.9 cm



35.5 cm 49.0 cm 55.9 cm



30.2 cm 37.5 cm 45.7 cm



10.8 cm 17.0 cm 25.4 cm



6.6 cm 11.5 cm 20.3 cm



7.9 cm 12.0 cm 19.1 cm



16.5 cm 22.0 cm 27.9 cm

Cucumber Plant 3-1


34.5 cm 50.0 cm 96.5 cm

Cucumber Plant 3-2


41.0 cm 64.0 cm 104.1 cm

Cucumber Plant 3-3


33.0 cm 47.0 cm 91.4 cm

Cucumber Plant 3-4


31.0 cm 21.0 cm 50.8 cm

Cucumber Plant 3-5


33.5 cm 26.0 cm 55.9 cm

Cucumber Plant 3-6


38.4 cm 47.0 cm 76.2 cm

Sweet Pepper Planted from 9.0 cm 20.0 cm 40.6 cm

80


Plant 3-7 seedling on June 28th.



7.3 cm 18.0 cm 35.6 cm



9.1 cm 19.0 cm 38.1 cm

81


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