Farmers intending to grow mushrooms for sale can use farm waste from their farms to grow the sweet food produce. The waste obtained from maize, sugarcane thrash, sawdust and banana leaves among other crops is ideal for mushroom growing because they thrive on a substratum.

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“Because it is a fungus, mushroom is not grown on soil like the green plants; it’s grown on broken substrate whereby the crop obtains its nourishment,” said Patrick Muchiri, a Biotechnologist at the Jomo Kenyatta University of Science and Technology (JKUAT).

“Mushroom is not a rain fed crop and requires little space for growing. The crop is steadily gathering pace as one of the preferred sources of investment in agribusiness with a promise of quick returns.”

According to official statistics from the National Farmers Information Service (NAFIS), Kenya, it reveals that there is a high demand of mushrooms. The country produces 500 tonnes of mushrooms per year against a demand of 1200 tonnes.

 Procedure of using agricultural waste to grow mushrooms

The agricultural waste, which is easily available on farms, is soaked for three days and then heaped for fermentation for four to six days in a closed container.

After the fermentation process, the agricultural waste is sterilized through boiling in closed pots for 12 hours in order to eliminate unwanted organisms and bacteria. After cooling, it is filled in small polyethylene plastic bags using common bowls, to serve as a substrate.

The substrate should be composed by 65 to 75 per cent of moisture, and for the remaining part by agricultural waste. It can be used for three harvests, and then it can be recycled as organic mulch or fertilizer. Alternatively, cotton seed waste can be used as substrate for oyster mushroom production.

Polyethylene plastic bags are filled with the substrate (about five kilograms per bag), which is then inoculated with the mushroom spawns (spawns are ‘mixed’ with the substrate). Each garden of about five kilograms of substrate is filled with about 250 grams of spawns.  At that time, plastic bags are closed manually.

Following the inoculation process, the mushroom bags are hanged in locally built (brick or mud walls and thatched roof), darkened mushroom houses for incubation. Ideal humidity of the incubation room is 70 – 75 per cent. Each room can host up to 300 gardens.

The mushrooms start sprouting after 28-35 days from inoculation. Each mushroom garden (i.e. plastic bag containing about five kilograms of substrate) yields a minimum of two kilograms of fresh oyster mushrooms.

Harvested mushrooms can be sold fresh, or they can be dried in a solar dryer and packed into plastic bags for sale.

Research done by JKUAT shows there is a huge shortage of mushroom supply locally. The main reason for this is that there was no institution that was producing certified mushroom seeds (spawn) before the university started production. At the same time, consumers were not aware of the health benefits derived from eating mushrooms. Mushrooms can substitute red meat because they have no cholesterol. They are rich in Proteins, and Minerals.

Spawn (mushroom seeds) can be obtained at the University at the following costs

• Button spawn, Agaricus bisphorus, agaricus bitorquise(Warm weather) @ Ksh. 600 liter.
• Oyster - Sh600 per liter
• Shiitake - Sh1000 per liter
• Ganoderma - Sh1000 per liter
• Casing soil -Sh6 per kg

 Ready substrate for sale:

• Button Substrate at Sh55 per kg for 10kg bag = Sh550, inclusive of casing soil.
• Oyster substrate Sh90 per kg
• Shiitake and Ganoderma substrates at Sh100 per kg

 An eighth acre farm can produce as much as two tonnes of produce. Each kilogram goes for an average price of Sh600 and this can translate t