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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Mary PeetMary Peet
www.ces.ncsu.edu/greenh
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Why Grow Organic?
Organic is big business in the US ($3.5 billion)
Growth in organic produce 20%/yr for past 5 yrs.
Overexpansion of greenhouse tomato industrymay drive down prices of greenhouse tomatoes
According to the 1997 USCensus of Agriculture,
compared to 1992, the # of
greenhouse vegetable
growers was up 35%.
(annual increase of 7%)
1978 1982 1987 1992 1997
0
500
1000
1500
2000
2500
3000
Numbe
rofFarms
Year
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Area of greenhouse
vegetables was up 35%
(annual increase of 7%)
Sales wereup139% (annual
increase of 28%)
1978 1982 1987 1992 1997
0
50000
100000
150000
200000
250000
Sales($1,0
00)
Year
1978 1982 1987 1992 1997
0
50
100
150
200
250
300
350
400
haofG
reenhouseVege
tables
Year
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Types of Organic Production Systems
Water-based (NFT, pipe
systems or float trays)
Solid media in trays, slabs
or containers
Low CEC-gravel, perlite,rockwool
Organic substrates (peat, coir,
compost)
Soil-based (most common)
QuickTime and a
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QuickTime and a
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Some Large Commercial Hydroponic
Operations-
Valley Fresh, Colorado
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Typical Problems using Organic
Fertilizers in Hydroponic Systems
Lack of sterility in system Diseases
Clogging from algae and other free-
living organisms
Deciding when to replace
recirculating water Relationship of EC (salt readings) to
available plant nutrients
Local, affordable sources of
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Profile of Industry No statistics, but groups
of organic greenhouse
growers in Quebec, NewEngland, California
Most grow in soil usingsame procedures as field
growers. Root diseases are
a problem, althoughcomposts may help
In south, solarizationpossible
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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ur Approach to
Organic
Hydroponics:
Soilless media with
higher water andnutrient retention
than perliteand
rockwool(peat,pinebark, coir) with
added compost
Organicallycertifiable media
ingredients &
fertilizers
Biocontrolsfor ests
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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No national standards-Yet!
Most groups have lists of materials that are approved,
restricted or prohibited. No genetically modified crops.
Brand-name products must be approved byO MRI(www.omri.org)
Criteria for greenhouses less well developed Some philosophical objections, e.g. not natural enough
Organic Certification in the U.S.
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Restrictions on Greenhouse Construction
General Allowed Restricted Prohibited
Transition period
may be required
if taking over
existing
conventional
greenhouseWhole house
must be
certified, but
can have
uncertified
houses o n same
farm if product
distinguishable
Proper
ventilation
required, but
emergency
use o f
portableheaters
allowed
Pressure treated
lumber only
allowed on
foundations
and end walls
(must beisolated from
growing media
and plants)
Artificial light
and shade
No asbestos,
urea, or
formaldehyde
No
biodegradable
plastic(Canada)
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Containers, Substrates
General Allowed Restricted Prohibited
Transplants
for fi eldproduction
require
organicpractices i f
available
Perlite ok,
rockwoolquestionable
Peat allowed
but compostpreferred;
Coir ok;
Recyclable
containers
(Canada)
Fiber
containerswith no
prohibited
material(NOFA,
FOG);
No synthetic
fertilizers,fungicides,
wetting agents,
or sterilants inpotting mix
Vermicompos
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Fertilization
Allowed Restricted ProhibitedCompost (N, K, Micros);
Colloidal soft rock and hard
rock phosphate (P);
Guano (P);
Wood ash (K);
Rock dusts [granite, feldspar,
greensand] (K);
Natural potassium sulfate (K);
Limestone, gypsum, calcium
oxide, (Ca);
Dolomitic limestone, Kierserite(Mg);
Kelp meal, liquid or powdered
seaweed extract, rock powders
(Micros); Commercial productson OMRI list
Sodium Nitrate (N);
Fish emulsion (N,
P);
Bone Meal (N, P);
Calcium Chloride
(Ca);
Epsom salts (Mg);
Chelate, acid
treated sulfate, or
oxide materials
(Micros)
Synthetic
Sources;
Muriate of potash;
Quick lime, or
hydrated lime
Earth Juice and
fish meal
fertilizers
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Pest Control
Allowed Restricted ProhibitedInsect Traps;
Insect Barriers;
Hand, Mechanical, or
Hydraulic Removal;
Biological Controls;
Alcohol to disinfect
benches, pots, tools
Steam sterilization, hot
water seed treatment,
low temperature bakingResistant cultivars;
Roguing or destroying
infected plants;
Herbal sprays
Oil Sprays; Insecticidal
Soaps; Bacillus
Thringiensis (BT);
Copper; Sulfur;
Approved Non-
synthetic Fungicides;
Bleach, hydrogen
peroxide and oxalic
acid for disinfection
Synthetic Pesticides,
Fungicides, and
Nematicides
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Issues before starting
commercial organic venture
Is the production system tested on tomatoes? Herbs, lettuce and transplants are not as nutrient-
demanding
Is certifying agency receptive?
Will the market pay a premium?
Is your philosphycompatible?
How do you feel about jumping through a lot of
hoops?
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Substrate:
Fafardspecial blend of 4-P to omit wetting agents,nutrient charge and micronutrients (85% by volume)
15% by volume Vermicycle(worm compost: 1.8-1.6-0.
1.5 lbs/cubic yard each of:
Blood meal
Bone meal
Potassium sulfate
O MRI-approved wetting agent Natural Wet at 2tablespoons/gal
0.5 lbs/cubic yard sulfur For other suggested potting mixes, visitwww.attra.org
Fertilization: Equivalentin all
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Fertilization: Equivalent in all
fertilizer treatments*
125 ppm N,
45 ppm P, 195 ppm K,
185 ppm Ca,
44 ppm Mg and
micronutrients
Provided at each watering (1/2 gal per plant per
day)
*would probably also work in recirculatingsystem
Fertilization-
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Fertilization-Magna Gro brand fertilizer consists of:
HydroponicBase Mix -analysis 2-3-6
ingredients: poultry compost tea, pasteurized blood meal, calcium phosphate,
and seaweed. This also contains trace minerals with fermented molasses in the
form of Zn SO4, Mg SO4, and Fe SO4. 19%N from poultry compost tea and pasteurized blood meal
K-9 -9% K2O from seaweed
Organic forms of trace minerals supplied as 6% B, 6% Fe, 6% Mg,and 6% Ca added, as needed based on tissue analysis.
For exact receipe, consult NCSU greenhouse vegetable
website
For other fertilizer sources, consult www.attra.orgwebsite
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Earth Juicebrand fertilizer consists of 5 separate
formulations:(N-P-K)
Grow (2-0.44-0.83): bat guano, Norwegian sea kelp, natural
sulfate of potash, feather meal, oat ran, blood meal and steamed
bone meal Bloom (0-1.3-0.83): bat guano, Chilean sea bird guano,
Norwegian sea kelp, natural sulfate of potash, steamed bone
meal, oat bran and rock phosphate
Catalyst (0.03-0.0044-0.083): oat bran, kelp, wheat malt,
molasses, yeast
Micro-burst(5% Mg, 0.02% B, 0.05% Cu, 0.2% FE, 0.1% Mn
and 0.15% Zn): kelp meal, magnesium sulfate, borax, copper
sulfate, iron sulfate, manganese sulfate, and zinc sulfate. Meta-K(10%K): from seaweed
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Method of addition
Injected into lines during daily
waterings(flush on weekends)
Fertilizers agitated by aquarium
pumps
Filtered to remove some, but not
all solids Pump adjusted to low dilution
rate (1:20)
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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New Materials Available, But Untested
Soluble Fertilizers
Natural Organic Grow from JedwardsInternational (organic
fish hydroloysate, OMRI certified)
Harmony Farms Omega 6-6-6 (certification status unknown)
Potting soils McEnroeOrganics
Southland Organic Mix (10% chicken litter compost)
Others: select the database on Organic Amendments at
www.ncsu.edu/organic_farming_systems/or search on
www.attra.org
i
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Many products Available for Home or
Hobby use
B t M N tb P ti li C i l
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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But May Not be Practical in Commercial
Production!
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Can Also Use Manure Teas!
Recmmendationsfororganicfertilization
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Recmmendationsfor organic fertilization
of soilless media (peat/pinebark): Constant provision of fertilizers at levels comparable toconventional mix (receipes on website & in newsletter)
pH and salts adjustment to prevent burning
Precautions with drip injection:
Low dilution rates (1:50 or 1:20)
Agitate with pump to prevent settling
Weekly water flush Emitters which resist clogging
Need some filtration, but nutrients not completely soluble
Processed fertilizers rather than fishmeal(too smelly!)
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8/8/2019 Organic Hydroponic Greenhouse Crop Production; by Mary Peet
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Unresolved issues in organic
fertilization in our system: Is flavor and quality different?
How do you reduce pH and salts?
Would our recommendations also work on inert
substrates such as perliteand rockwool with low CECand in recirculatingsystems?
How do you increase potassium and calcium? Are there more affordable alternatives?
Will animal waste products work and be allowed?