For mushroom cultivation, straw is cut into 2 to 3 cm pieces and soaked in water overnight (weigh it down so it stays submerged in water the whole time). Afterwards, straw is completely drained and steamed for 1 ½ or 2 hours (Picture 1); alternatively, it can be submerged in hot water, heated to 60°C or more, for an hour.

Picture 1: Steaming of straw. 1-lid, 2-opening, 3-straw, 4-water, 5-gas burner, 6-grid, 7-gas bottle

Once the straw is cooled to below 30°C and completely drained, it is mixed with grain spawn, which should be done as clean as possible.

The straw is put into black plastic bags with clean hands, while simultaneously spawn is evenly added (Picture 2). Once the bags are filled, we shake them to mix the contents evenly.

Two kg of grain spawn is used for 100 kg of wet straw. However, the higher the spawn ratio, the lesser the possibility of contamination with moulds and bacteria, the faster the overgrowth and the higher the yield.

Picture 2: Mixing the spawn into the straw

Afterwards, the contents are slightly compressed by gently shaking or tapping the bags to the floor a couple of times. Do not use your hands, because the contents must remain airy. The bags are then firmly tied and small holes made over its entire surface by using medium-sized nail, pencil or a screwdriver (Picture 3). The bottom corners of the bags are cut off to allow the excess water to drain out. This prevents water from collecting at the bottom of the bags and consequent rotting.

Picture 3: Making holes in a bag for aeration and for the mushrooms to grow out of

The bags are kept in a warm (20 to 24°C) environment for a month and then transferred to a colder place (below 20°) with high humidity and dim light. Under these conditions mushrooms will grow from the substrate. During the mushroom growth, it is recommended to spray the room with water daily; however, mushrooms should not be soaked, as they may rot. Do not remove plastic bags covering the substrate, because mushrooms will grow through the holes in the bag (Picture 4). If necessary, holes can be enlarged. Eventually, up to three flushes of mushrooms can be harvested from a bag.

Picture 4: Mushrooms growing from holes in plastic bags

Once mushrooms stop growing, the remaining straw can be applied to fresh logs to inoculate them for further mushroom cultivation. However, only straw that have not rotted or dried up during the mushroom cultivation is appropriate for this purpose.