Saturday, 9 June 2012

Guide to Small Scale Mushrooms Farming

Oyster Mushrooms ~AIRC
Mushrooms are a form of edible fungi which grows on decaying matter called substrate. They begin as spores, the reproductive structures, and grow to form a network of small whitish strands/filaments called mycelium. Its from here that the mushroom you feed on originates.People tend to have perceptions that all mushrooms are poisonous while others think its a preserve for the who is who since they are expensive.This deters small scale farmers in to venturing in to mushroom business.
Advantages of Mushroom Farming
  • Its a sustainable farming method as it utilizes agricultural wastes in the form of substrates
  • Possible to have a lot of produce in a small unit area.
  • Source of high end nutrients and a perfect diet for diabetics and  those interested in watching their weight.
  • After farming, you can use the substrate as a soil conditioner.

There are are about 1.5 million species of mushrooms in the world and only 30 species  are domesticated and deemed  edible and useful for medicinal purposes.Find out more HERE . Common types in the country include; Oyster variety(Pleurotus spp) and the Button Variety(Agaricus spp). A detailed survey of each one of these will be available in the the next posts.
Nutritional Component of Mushrooms
Mushroom have a high nutrition value which comprises of:
  • Vitamins: B complex, C,D,niacin, riboflavin, thiamine, and folate.
  • Minerals:Phosphorous,Potassium,Zinc,Calcium,copper , Iron, Magnesium.
  • Provide carbohydrates and have no starch.
  • Protein: of high quality estimated to be between 19 and 35%.They are a good substitute for red meat.
  • Medicinal properties of boosting the immune system,Lowering the level of lipids and regulating blood pressure  making it suitable diet for diabetic patients.
  • Low on fat and fibre.
Factors to Consider Before Venturing In To Mushroom Farming
i) Availability of market(Very Important). This ranges from the prices in the market of the particular type of mushroom to the value  addition process,the current demand and availability of produce during the production period.
ii) Availability of substrate.Different types are used among them being straw, sawdust , wheat bran,coconut fibre,cotton straw.. 
iii) Availability of spawns and those of exceptional high quality*Spawns are the mushroom seeds*. A  guiding factor to how much spawns one needs is the substrate The amount of spawns needed should equal 4-6% of the wet weight of the substrate
Spawns in a bottle:Photo AIRC
iv)The Mushroom House:
Before deciding to build mushroom house, one needs to take in to consideration various factors like the distance to the market and the availability of clean water.
Mud walled mushroom house: Photo AIRC
Most preferred structure for small scale farmers is a mud walled house like the one above as it  is able to maintain cool temperatures and high humidity, which are important conditions.The floor is left to stand on arable land.Important to note that all openings that let in free flow of air ,be it windows or doors, should be closed or a wire mesh put in place to filter out insects like mushroom flies which are attracted to the smell of the mushroom mycelium.
Create some wooden shelves for holding the bags in place as they fruit.They should be ideally constructed at a height of 1.5m above the ground and a metre apart to allow for easy manourvre inside the house.

Wooden Shelves in the mushroom house.Photo AIRC
Phases in Mushroom Cultivation:
Composting :Time span dependent on the substrate chosen.Roughly its between 6-14 days.Involves the wetting of substrate with water and in advanced cases, addition of supplements like gypsum.The rule of thumb in the wetting process is a squeeze of the substrate should give 2-3 water drops. If the drops are few, add water.If they are more continue with the draining process. Moisture content at this point should be at 70%.
Pasteurization : Depends on the method of pasteurization preffered. Heat sterilization is the most commonly preffered. Involves about 4-6 hours of heat treatment of the  substrate  at 60°C the subsequent cooling before putting it in bags.This is meant to destroy all microbes that might contaminate the process.Conditioning is also done to remove excess NH3.Substrates moisture content should be between 67-70%.
Spawning and growth: Different for each species but roughly takes between 5-15 days. It Involves putting spawns in the substrate plastic bags with relative humidity maintained at 65-70%.
Casing: Not applicable to all mushroom species. It involves dressing the colonized substrate with a thin layer of wet top soil combined with murram and lime with the aim of inducing pinning. Substrate will change colour from white to gray indicating the start of fruiting.Takes about 13–20 days with temperatures maintained at 25°C.
Pinning:Takes about 5-10 days with temperatures kept between 23-25°C.Its at this stage that fruiting occurs and pin heads (small mushrooms) begin to occur. Relative humidity should be maintained at 85-95%.
Harvesting: About 30-40 days after spawning.

Yield and Post Harvest Handling
Yield is highly dependent on the type of substrate used. For instance using wheat straw at 50-100% one would expect  to harvest between 50-100kg of mushrooms. Harvested mushrooms have a short shell life of up to 3 days  in very cool conditions after harvest.Where possible, they should be sold fresh or preserved and value added by drying,canning or grinding.
Training Centres:
In Kenya these institutions are credited with provision of expert advice on Mushroom Farming:

  • Jomo Kenyatta University Of Agriculture and Technology,Juja Campus (JKUAT) :Contacts:Tel: +254-067-52711, +254-067-52034, +254-067-52117, +254-067-52028
  • Ministry of Agriculture~ Agricultural Information Resource Centre email:
PS:Don't know how to prepare a nice meal using mushrooms? Sample some mouth watering recipes HERE 

References and Further Reading:
Make Money By Growing Mushrooms:FAO Diversification Booklet
Agrodok 40: Small Scale Mushroom Cultivation
InfonetBiovision:Mushroom Crop
Mushroom Growing


  1. We had a neihbour who used to grow mushrooms, the problem is they used to small as hell. I think that was the time when they would turn that thing called the substrate.

    Anyways, do you think that's an enviromental concern that farmers shud consider?

  2. I have read that we know very little about mushrooms compared to some other foods. So I am sure there are tons of benefits that we have not even discovered yet. cubensis spores

  3. A very incisive piece. keep it up.

  4. Thanks Jed. Glad t was of some help