Table of Contents Page

Acknowledgements................................................................................3About this Guide.....................................................................................41.0 Introduction................................................................................51.1 Objective.......................................................................................61.2 Common Terms Used In Mushroom Production.............................72.0 What are Mushrooms?...............................................................................82.1 Edible Non-Edible and Poisonous Mushrooms...............................82.2 Value of Mushroom Production......................................................82.2.1 Nutritive Value..............................................................................82.2.2 Medicinal Value.............................................................................92.2.3 Utilization of Agricultural Wastes..................................................92.2.4 Spent Mushroom Compost..........................................................102.2.5 Employment Potential.................................................................102.2.6 Absence of Crop Competition.....................................................102.2.7 Economic Importance................................................................113.0 Oyster Mushroom Production.............................................................113. 1 Requirements For Growth of Oyster Mushroom..........................113.2 Preparation of Compost..............................................................133.3 Spawning....................................................................................144.0 White Button Mushroom Production..............................................154.1 Requirements for the Growth of White Button Mushroom..........16

4.1.1.The Concrete Slab...............................................................................164.1.2 Horse and Chicken Manure..............................................................164.1.3 Casing Soil.............................................................................................164.1.4 Spawn......................................................................................................17

4.2 Growing Systems........................................................................174.3 Growing Conditions.....................................................................184.4 Compost Making.........................................................................184.5 Spawning....................................................................................204.6 Casing.........................................................................................215.0 Harvesting of Mushrooms.....................................................................226.0 Marketing of Mushrooms.......................................................................237.0 Mushroom Preservation and Processing......................................23

7.2.1 Canning...................................................................................................257.2.2 Drying.....................................................................................................25

8.0 Disease Control............................................................................................269.0 Temperature Controls....................................................................................27

2

Acknowledgements

This manual has been produced as a simple reference for urbanfarmers. It has been observed that most urban farmers engage insimple UA activities which they are familiar with like the cultivation ofleafy vegetables and other staples at the expense of other marketoriented crops like mushrooms. The main reason for this trend is thelack of knowledge and skills on how to produce such crops. Thismanual is therefore designed to impact the knowledge and skills tourban farmers wanting to venture into mushroom production.

MDP acknowledges and is grateful to the RUAF Foundation for thefinancial support for the production of this manual. With the financialsupport of RUAF it was possible to hire a consultant to produce the firstdraft of the manual which was later edited and revised by the MDPKnowledge Management Unit.

Special thanks go to Mrs Shalene Mabharani for producing the initialdraft of the manual. The Bulawayo Core Team was instrumental inidentifying her for the assignment. We would also like to thankcolleagues from MDP, in particular, the Knowledge and InformationManager, Mr. Phillip Kundishora for editing the manual. Mr. GeorgeMatovu, the Regional Director, was a source of encouragement in thequest for the production of knowledge materials. Mr. Percy Toriro alsoassisted with reviewing the initial drafts.

We would also like to thank the Bulawayo UA team for their patience aswe put together the manual. They have always pointed to the need forsuch materials if UA is to take-off in an economically sustainable way.

Thank you all.

3

About this GuideThis manual is designed for use by urban farmers who want to go intomushroom production. The objective of this manual is to providetechnical information on the growing of mushrooms to urban farmersso that they can be able to produce mushrooms for subsistence as wellas for commercial purposes using their limited resources. It is designedin such a manner that farmers can easily follow the steps for theproduction of mushrooms. First the manual gives background on thevalue of mushrooms. This is then followed by simple productiontechniques for both oyster and button mushrooms. The last section ofthe manual deals with the harvesting, processing and marketing ofmushrooms. It is our hope that the manual will help urban farmersimprove their knowledge and skills of producing mushrooms.

4

1.0 Introduction

Throughout the Eastern and Southern Africa region, mushrooms have

become a popular vegetable due to its culinary appeal as well as a

source of vitamins and protein. The mushroom roadside stalls found

during the rainy season along most major roads and vegetable markets

in urban markets bear testimony to the fact that they are having some

contribution to the economic well being of the community.

In addition to their nutritional value, mushroom production is a very

profitable enterprise which requires minimum land size which is a

factor to be considered for urban producers. The by-product, spent

mushroom compost is a valuable source of organic matter which is

used in horticultural crop production.

The mushroom industry is based on two main sectors, being the

cultivated mushroom consisting mainly of the white button and oyster

mushroom and the indigenous mushrooms collected from the wild.

For the past number of years, Zimbabwe has been experiencing price

rise on basic commodities, yet the sources of income, especially from

formal employment, did not ensure increases to cater for price hikes.

People countrywide therefore started embarking on agricultural

activities to boost their income, amongst which are poultry, vegetable

and at a lesser extent mushroom production. Due to the increase in the

number of people keeping poultry and growing vegetables for the

market, demand for these products became reduced thus more people

tend to be now turning to mushroom production.

5

Land which is also limited for vegetable production in urban and peri-

urban areas, is also another factor contributing to the people’s need to

look into mushroom which is grown indoors and the environment can

be manipulated so that production can be carried out throughout the

year.

1.1 Objective

The objective of this manual is to provide technical information on the

growing of mushrooms to urban farmers so that they can be able to

produce mushrooms for food as well as selling for extra income using

their limited resources. This can be achieved as:-

Mushrooms are grown indoors and require minimum land size

thus do not compete with other horticultural crops

They can be grown in available rooms, which may be cottages,

garages, basements, or any unused rooms at any urban setting.

Mushroom growing utilizes residues which might otherwise be

considered useless, thus it is cheap to produce.

Due to the time taken from spawning to harvesting, mushrooms

have a quick turnover.

Labour requirements after spawning are minimal; therefore a

mushroom crop can be run with minimum as a part-time activity.

6

1.2 Common Terms Used In Mushroom Production

Pasteurization - the removal of all inserts, pests, nematodes,

harmful fungi and their spores

Conditioning - driving off the remaining ammonia from

prepared compost

Actinomyces - beneficial heat loving organisms that indicate a

well made compost

Stoma - a dense proliferation of mycelium

forming on the

surface of the compost and casing soil

indicates

vegetative and therefore non-fruiting growth.

Spawning - this is the process by which the spawn is

introduced

into the prepared compost. It is usually

conducted

in a room specifically set aside for the purpose

of exclusion of contaminates and insect pests

which is important at this stage.

Mycelium - the root structure of the mushroom which

appears as a network of lacy white filaments.

Casing - a layer of material, usually soil or peat mass,

placed on the surface of a substrate to

stimulate

fruit body production.

Substrate - the material, usually organic, on which

mushrooms grow.

7

8

2.0 What are Mushrooms?

Mushrooms are members of the fungi kingdom. They are lower plants

which, unlike higher plants do not have chlorophyll which enables

plants to use nutrients, water carbon dioxide and energy from the sun

to make their own food. This therefore means that mushroom cannot

produce their own food and thus depend on higher plants for food.

Mushrooms obtain nutrients from organic materials to facilitate their

breaking down into basic nutrients.

2.1 Edible Non-Edible and Poisonous Mushrooms

Generally, mushrooms are obtained from the forests during the rainy

season. Some of the wild mushrooms are very delicious and are in

demand for food. However, there are other mushrooms which are not

good enough for food because they lack taste and flavour. Some

mushrooms are very poisonous and consuming them may result in

death, thus the need to cultivate known varieties arose.

2.2 Value of Mushroom Production

2.2.1 Nutritive Value

Mushrooms are highly nutritive vegetables. The nutritive value of

mushrooms, white button in particular, ranks above most vegetables

except soya beans and spinach. They are also a good source of iron,

potassium, phosphorus in addition to folic acid, an ingredient known for

enriching the bloodstream and preventing deficiencies, calcium and

9

are high in fibre. They also contain high percentages of vitamin, B1,

B2, B3, and K. They are low in fat and therefore ideal for diet

-conscious people. They can be eaten as they are, cooked or raw,

unlike other protein sources such as soya and yeast that have to be

processed or disguised in some manner before they are acceptable on

the table.

Although devoid of vitamin A, mushrooms contain high levels of

riboflavin, thiamine and nicotic acid. Their content of antepellegra

vitamin, niacin is nearly equivalent to the levels found in pork or beef,

considered to be the richest sources of this vitamin. Mushrooms are

low in sodium, making them ideal for persons with certain types of

heart and kidney ailments.

2.2.2 Medicinal Value

Mushrooms have been prescribed for various ailments for centuries.

Research has shown that some of the medicinal claims are not myths

as most people used to believe but have scientific basis. A vast body of

information exists in the scientific literature, dating back to the 1940s

and 1950s (Qumio, et al). Some mushroom species contain a high

amount of retene, a substance that may, in some circumstances have

an antagonistic effect on some forms of tumor. Intraperiontoneal

injection of aqueous extracts of some mushrooms has some inhibitory

effect on the growth of tumours. Some mushroom extracts have also

induced the formation of interferon, a defense mechanism against

some virus infections and have displayed hypocholesteroemic activity

or an ability to lower cholesterol level.

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2.2.3 Utilization of Agricultural Wastes

Mushrooms are grown, not directly on soil as are other crops, but on

organic substrates, either raw or composted. These substrates are

mostly waste materials from farms, plantations or factories. These

otherwise useless by-products can be recycled to produce additional

food in the form of mushrooms for human consumption. This also

reduces environmental pollution by the

by–products like straw, corn cobs, sawdust, baggasse, wood pulp,

cotton

wastes, banana leaves, as well as tree leave and the bark.

2.2.4 Spent Mushroom Compost

Spent mushroom compost is a viable source of organic matter, which is

used in horticultural crop production. Used compost from mushroom

growing may also be recycled for use as animal feeds, soil conditioning

and fertilizer. It can also be sold to nurseries and vegetable producers,

hence maximizing profits.

2.2.5 Employment Potential

Mushroom cultivation involves various technologies depending partly

upon available substrates, but most of all upon the provision of capital

for the equipment required to facilitate and simplify the different steps

involved. Most of the low cost methods suitable for urban projects are

labour intensive and can provide employment in the peri-urban and

urban areas. In fact, some methods may use family labour thus

providing all members of the family with employment.

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2.2.6 Absence of Crop Competition

While the availability of land may be a limiting factor in most crop

production operations, it is not so for mushroom culture. Mushrooms

require little space because they can be grown inside mushroom

houses, basements, garages or other suitable areas within the house.

2.2.7 Economic Importance

Economically mushroom production plays a very important role. Urban

growers can produce mushroom to sell to other consumers, thus

increasing their income levels. By producing their own mushroom for

food, growers will also cut down on their expenses of buying thereby

saving their money.

3.0 Oyster Mushroom Production

Plate 1: Fruiting bags of Oyster mushroom hung on rails

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3. 1 Requirements For Growth of Oyster Mushroom

1. Substrate (compost)

Any of the following residues is suitable for the cultivation of oyster

mushrooms

Bush grass – obtained from the bush or along the roads as well

as unused land

Wheat straw or any cereal straw - can be obtained from peri-

urban farms where wheat is grown.

Sawdust – one can get it from carpentry shops

Water hyacinth - from dams

Maize stover - obtained after harvesting, i.e. stalk and leaves

Maize pulp – left after shelling the maize

Soya bean/bean hay stalks –left after harvesting

13

2. Chopper or shredder for the crop residue

This process is done by hand and it is necessary for easy

handling of compost.

3. Bags for growing

These can be large (50kg fertilizer size) (10kg fertilize or orange

size ) or anywhere in between depending on the size of

operation.

4. Growing rooms

Any room can be used from within the house, cottage, garage or

basement, other unused rooms can also be modified for

mushroom growing

The choice of the growing structure may be based on

- building costs

- type of mushroom technique (tray, bag, rack etc)

if a large room is to be used, shelves would be necessary to

optimize space and ensure continuous production

shelves could be filled at intervals of 1, 2 or 3 weeks.

it is possible to hang the bags from the ceiling or horizontal

supporters.

the growing rooms should be designed in such a way that they

are constantly humid (RH95%) and the temperature at 20-30

degrees Celsius and have ventilators that can be opened and

closed when necessary.

3.2 Preparation of Compost The substance should be clean, free from moulds and

undecomposed

14

The material is chopped into 7.5 cm pieces

Soak the substance in water overnight before boiling

There are two methods of pasteurization

- The chopped substrate is pre soaked to approximately 75% water

and steamed in a container for 2 to 4 hours at 60-70 degrees

celcious or

- for 12 to 24 hours at 50 degrees Celsius

Plate 2: Pasteurizing substrate using a drum

3.3 Spawning The spawned substrate is packed into the bags and placed on

the shelves or hung up in the growing room.

Use 500grams of spawn for 10 kg of substrate

Apply a layer of substrate into the bag then a layer of spawn

follows.

15

Continue applying substrate and spawn alternately until the bag

is full as shown in Figure 1

The bags are then tied and hung in a mushroom house with the

Plastic bags must have holes punched 6cm apart right round to

allow the mushroom to grow out of the bag.

Figure 1: Spawned bag ready to be hung

Layer of uniformly distributed

spawn

Pasteurized substrate

Table 1: Growing conditions and duration of different

environment conditions required by oyster mushrooms

Procedure Conditions Period Spawn run Windows closed

Dark room Daily watering

Until substrateappears white (2-4)weeks

Fruiting Windows opened Daily watering

After substrate hasappeared white

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Light required Misting of bags

Harvesting Windows opened

Daily watering and misting of bags (except 2-3 days before picking.Light required

Once fruiting starts mushroom can be pickedWithin 2-4 days.

Harvesting will continue for up to 5-6 months from the date of planting.

4.0 White Button Mushroom Production

Plate 3: Fruiting white button mushroom ready for harvesting

4.1 Requirements for the Growth of White Button Mushroom

4.1.1. The Concrete Slab

17

Slanting concrete slab and shallow concrete pit at the end of the slab

all under a roof. The slanting of the slab enables excess water to drain

into the pit at the end of the slab.

4.1.2 Horse and Chicken Manure

The horse manure forms the bigger part of the mushroom compost,

therefore the grower must establish a regular source of supply before

hand. Wood shavings in the horse manure can be a hazard therefore

must be avoided completely by the beginners.

Use chicken manure with grass bedding

Both the horse and chicken manure must be fresh always. The ratio is

about 150kg chicken manure to one tonne of horse manure.

4.1.3 Casing Soil

Pitch-black veld not field alluvial soil pH 7 is best for casing soil. Some

growers use red soil mixed with very old used mushroom compost.

Growers are warned never to use clay soil as this tends to be heavy

and too hard for the mushrooms.

18

4.1.4 Spawn

Of all the ingredients needed to grow mushrooms, spawn is the most

difficult to get. The local suppliers are not reliable and their spawn is

not that good. Therefore some Zimbabwe growers tend to set up their

own spawn laboratories not for sale to the public, or they import from

South Africa

4.2 Growing Systems

The size and location of the growing house depends on the space

available to the grower

A brick wall under thatch or asbestos is best.

Durawall and plastic or sackcloth (can also be used in guarded

conditions).

Wooden trays (are widely used for growing white button

mushrooms and as many as ten trays can be piled together) but

they must be secured and made easily accessible.

Wooden, steel and mesh wire shelves are becoming more and

more popular for they are easy to work on.

Plastic bags or used cement bags can be used as they are best

for disease control but there is limit to their use due to space and

their durability.

Nylon or metal shelves can be used though there can be a

problem in air circulation if not carefully planned, otherwise they

are as easy as the wooden shelves if not better.

19

4.3 Growing Conditions The growing house must be totally dark all the time

Lighting must be used only when absolutely necessary e.g.

when spawning casing, watering and harvesting.

There must be a thermometer in each house - alcohol red for

temperature as well as hygrometer for humidity

Watering is done by fine spray fixed to a horse

The doors and air vents must be away from composting area

There must be a table for loading the harvest.

Air fans can be supplied if one can afford.

No tool or chemical should be stored in the growing house

No visitors and pets should be allowed in the growing house

as mushroom would adopt the smell of animals, tobacco and

perfumes.

4.4 Compost Making

Gather all your requirements before you start making the compost as

follows depending on the capacity of your growing house

Horse manure = 2 tonnes

Chicken manure = 10 x 50kg bags

Ammonium nitrate = 5kgs

Calcium sulphate = 50kg or 100kg (Gypsum)

Gather manure by the concrete slab

Fill the pit with clean drinking water from the tap

Soak the horse manure in the pit bit by bit and start building

the compost at 1 m width, 4 m length and 1 m height.

20

Stop at 30cm height level and add 2 to 3 bags of chicken

manure and sprinkle the gypsum on top.

Continue to lay and build the compost stopping at every 30cm

height level adding 2-3 bags of chicken manure as well as

gypsum.

Add Ammonium Nitrate in the water being used in the first

making of the stack, you can also apply it later during turning

of the compost

Put enough water during making. Even if it drains into the pit

take it back onto the stack

Add the dry chicken manure on the different layers of the

compost

Figure 2: Laying the compost

Gypsum

Chicken manure

Horse manure

Leave

the stack to mature for two days during which the compost must

be kept wet at which time the compost emits the ammonia smell

Turn the stack after two days and apply gypsum for the last time

and add water again.

Turn the stack again for the third time and add water if possible.

Turn it once every 2-3 days for 8 to 10 days. Make sure the stake

has got the right amount of water content. (Squeeze by hand to

Pit to hold water from compost

21

ensure the right water content. You should be able to see only

few drops of water)

At day 5 or 6, the compost should adapt the smell of mushroom.

Cover the whole stake with polythene and raise the temperature

to 60 degrees centigrade. Maintain the temperature for 7 to 8

hours or more, and then remove the plastic. You can also

pasteurize with formalin.

Pasteurization can also be done by covering the stake with

polythene and introduce steam heat

Figure 3: Pasteurizing the compost using a drum steamer with

a hose pipe

200l drum

half filled with

water boiling to

release steam

into compost

Fire

Fumigate the whole house with formalin or jik before laying

compost on the beds

Leave the compost covered with plastic polythene for a day or

two to allow for conditioning

4.5 Spawning

Hose connected from boiling drum of water to compost

Polythene covering compost

Compost

22

Once the beds or trays are filled with compost, spawning can be done.

Four layers of compost are ideal with spawn applied after each layer,

See Figure 4

However, due to the ever-escalating price of the spawn, other

spawning methods can be used. For instance a heavy applications of

spawn on top of already filled beds or trays can be turned in with

fingers, then sprinkle very lightly the surface of the beds with another

layer of spawn. The level of the beds must be maintained in all these

processes. Spawned beds are firmed or hard pressed. Spawned

compost can be covered with clean newspapers that are kept moist

during the entire spawn-running period of 12 to 14 days. After

spawning, spray with formalin over the newspapers using one cup of

formalin to 15 litres of water. The spawned house should be maintained

at 25 to 27 degrees and this is very important because mycelium only

develops under those conditions.

Figure 4: Spawning in a tray

60 cm

90 cm

A tray measuring 90cm length, 60cm width and 30cm height can

be used.

For every 65kg of compost, use 300 grams of the spawn.

Compost

Layer of spawn

23

4.6 Casing When the spawn has been run, casing should be done straight

away.

Pasteurized black or red soil or peat or spent casing material

with a pH 7.5 is used for casing the beds.

The cased room should be closed, including the air vents so that

the mycelium will come through the casing layer.

After 5 days, venting off (introducing air into the house) can be

done by opening the air vents slightly and switching on the fan to

supply air to the house. Air circulation is very important at this

stage.

Water the room by misting using a sprayer or hose with a fine

nozzle.

Avoid over applying water as the compost already has got

adequate moisture for fruiting bodies to grow.

Keep checking the water content during fruiting, if necessary add

more water.

Remember, too much water kills the spawn-run or the mycelium,

which produces the mushrooms.

Mushrooms grow in flushes or breaks of roughly 7 days interval.

Harvesting compost lasts for 40 to 60 days from first day of

picking.

The first two flushes yield more than half of the potential

Compost.

24

5.0 Harvesting of Mushrooms Do not apply water before picking. Dry mushrooms are clean

mushrooms virtually.

Watering can be done the day or night before picking.

Handle the mushroom firmly with your fingers and twist the cap.

Do not destroy the growth by creating large holes when picking.

Trays are the best for collecting mushrooms from beds.

Do not pile up mushrooms before cutting off the roots.

Use a sharp knife and small paintbrush to remove the roots and

dirty particles on the harvest.

Do not remove big chunks at the bottom of the stem

Cleaned mushrooms can be packed in baskets and basins of any

size including aerated cardboard boxes or plastic containers.

6.0 Marketing of Mushrooms

There is no centralized marketing system for mushroom in Zimbabwe.

Each grower therefore markets his or her own mushrooms with major

buyers including hotels, hostels, restaurants, fast food outlets,

supermarkets, hospitals, schools and boarding establishments, food

processing companies or manufactures as well as horticultural produce

dealers and some few individual buyers. Most of the mushrooms are

sold fresh with very few sold as dry in few shops and market stalls.

For the urban growers, mushroom is a brisk business as there are only

a few growers making demand for product higher than the supply.

Selling the product should be done quickly while it is still fresh,

therefore growers should establish their markets well.

25

7.0 Mushroom Preservation and Processing

7.1 SHORT TERM STORAGE

Refrigeration may extend the shelf life of mushrooms from 1

day to 2 weeks depending on variety as they may suffer from

chilling injury.

Preservation of mushrooms at cool temperatures generally

results in effective short-term preservation by

(i) Retarding the growth of micro –organisms

(ii) Reducing the rate of post harvest metabolic

activities of the mushroom tissues

(iii) Minimizing moisture loss

Urban farmers can therefore package their produce at 200g, 250

g or 500g depending on the market requirements see plate 4

showing oyster mushroom packed in trays and white button in

plastic containers.

Plate 4: Short term storage of mushrooms

Oyster mushroom in trays White button mushroom in

containers

26

7.2 LONG –TERM STORAGE

For long-term storage and mushrooms, canning, pickling and drying

processes are employed. However, the quality of the finished product

is rarely comparable with that of fresh mushrooms. Furthermore, these

processes are not always suitable for all types of mushrooms.

7.2.1 Canning

Although canned mushrooms are not common in Zimbabwe, it is the

ideal process used in other countries for the white button.

7.2.2 Drying

Drying is another way of preserving edible mushroom. In Zimbabwe,

most commonly dried are the indigenous and oyster mushrooms.

Mushrooms preserved by drying have a good flavour and the drying

prevents deterioration. Dried mushrooms are convenient for long -term

storage.

The most common method used in drying mushrooms is sun drying.

However, after drying, the mushrooms should be properly stored in air

and moisture tight containers since they can absorb moisture from the

air an get bad.

27

Plate 5 shows sun-drying of oyster mushrooms

28

8.0 Disease Control

High standards of cleanliness must be maintained from the beginning

to the end of the mushroom growing process. Clear /clean water must

be used and general hygiene strictly maintained always.

Pasteurization kills pathogenic fungi, bacteria, viruses,

nematodes and insect larvae.

Boilers and steam pipes are the most efficient ways of treating

your compost. However recommended chemicals can also be

used as prescribed e.g. formalin or jik (bleaching agent)

Lack of adequate air circulation when required can be a cause for

contamination in the growing house.

Avoid leaving the door open for too long as this can also

introduce diseases from outside.

Put enough formalin on the doorsteps

Sterilize the compost and casing soil well.

Keep the floors swept clean especially after composting and

casing the beds.

Do not allow any visitors, children or pets in the growing house.

Sterilize the growing house properly before and after each crop.

Do not keep the cut off bits of the mushrooms after harvesting

Burn the newspapers used during the spawn –running period.

Apply chemicals as recommended or as per manufacturer ‘s

directions.

Green mould can be cured by Dithane mix of 1 of 10

Mummy disease shows through thick stem and small head of

your crop.

Mix 1 to 20 parts of formalin regularly during fruiting.

29

At the end of a mushroom crop, the growing room and its contents

must be cooked out with live steam at 60-70 degrees celcius. These

temperatures must be held at least 10 hours. Chemicals can also be

used to repasteurise the growing house. The used compost should be

removed and used as garden fertilizer. Nurseries buy it as good prize

also.

9.0 Temperature Controls

Below are the methods that a grower can use to control temperature in

the growing house. It is advisable for urban growers to use the

cheapest method.

HOW TO RAISE HOW TO LOWER IT

1. Use electric heaters 1. Use air fans

- Mind electric bills - Mind electric bills

2. Apply steam boilers 2. Pour water on the floor

- Best method - Always, whenever

3. Burn charcoal in tins 3. Put ice cubs on the floor

- Mind smoke and the flame - Best method

4. Keep air vents closed 4. Open some air ventilators

- Use adjustable air events - Use adjustable air vents

5. Light a few candles 5. Put the house under some

change

- Mind the light and fumes - If possible

6. Pour hot water on then floor 6. Insulate the house

- Very good method - Use grass or kaylite

30