This is my first post of the button manual that I am giving out for free, I will post chapter by chapter.


Nutritionally, mushroom rank above most vegetables in protein content and have significant levels of the vitamins B and C. They are low in fat, rich in minerals such as calcium, phosphorus potassium and iron, and are believed to have varied medicinal properties.

In Zimbabwe, there are mainly two types of edible mushroom grown for the fresh produce market: Button, (agaricus bisporus) and oyster mushroom, (pleurotus ostreatus). Production of oyster has been increasing at a fast rate and popularity is increasing. Button was the first to be grown in Zimbabwe. Button is usually sold fresh, but oyster mushrooms are sold either fresh or dried. The production methods are different and this manual will concentrate on the growing methods for the agaricus species.

The most cultivated mushroom in the world, agaricus bisporus, is not easy to grow in our climate, but with attention to details and perseverance it is the most rewarding crop. Several growers in this country have built complex and costly facilities but many small growers have established simple but effective units that have proved most successful. It is possible with a very small capital outlay, to produce mushroom for home consumption and/or commercially. One thing I would like to mention here is that it is impossible to commercially without having air conditioners (the air conditioner must be able to heat and cool the room automatically, if its not automatic then some one has to be always watching the temperature). Many people tell me they want to grow button because its more lucrative, what many people do not realize the price take into consideration the air-conditioning costs which also include costs of running the generator, with power cuts so frequent one must have a standby generator. Simply put button mushrooms are capital intensive.

To fully understand the whys and wherefores of mushroom production it is important to understand the biology of mushrooms which are members of the fungi Kingdom. Fungi, unlike plants, do not contain chlorophyll and are therefore unable to manufacture their own food using carbon dioxide and sunlight. They totally dependent on organic materials for food, growth and energy and this is provided by specially prepared compost or substrates. Fungi are sensitive to temperature and humidity. Low temperatures (15?c and lower) will slow down the growth of mushrooms. High temperatures (above 30?c) will cause degeneration and death of the mycelium. Freezing will destroy the mycelium.

The fruiting body of the Agaricus Bosporus mushroom is the mushroom cap and stalk (stipe) that we buy in the supermarket. On the underside of the cap of an open mushroom, pink or dark brown gills, depending on the age of the mushroom cap, can be seen. Inside these gills, many millions of minute, microscopic spores are produced which are the equivalent of the seeds of chlorophyll – containing plants.

When a spore germinates a fine thread like strand of mycelium is produced. As the mycelium grows, a network of threads is formed. The mushroom plant is produced by the growth of primary mycelium from one spore which mates with the primary mycelium of another spore to produce secondary mycelium. Fruit body initiation occurs at the next stage in the life cycle. The fine filaments of the mycelium knot together to form pinheads which develop into minute, ball – like masses called primordial. These will eventually enlarge into the mushroom fruit body.

Prepared compost is an ideal environment for the growth and support of all other Fungi, bacteria, nematodes, mushroom flies and almost every other creepy crawly that can be imagined. Throughout the mushroom growing cycle, from the beginning of compost preparation to the disposal of the spent compost after the mushrooms have been harvested, very strict measures must be taken to exclude the competitors and contaminants from the crop. This means that any openings into the growing rooms should be covered with insect screens. All utensils and equipment should be washed and sterilized after use. All hands should be washed before entering growing rooms. The area around the mushroom unit should be free of vegetation which harbours pests.

Unpasteurised compost should occupy a position downwind of the unit. The doorway to each growing room should have a disinfectant foot bath. Workers should use clean protective clothing when working in the growing rooms. At the end of a crop, the spent compost should be removed and disposed of away from the unit either to be used as nursery compost or to be broken down to add to casing material. The growing rooms should be swept, washed down with a hose pipe and sterilized by one of several accepted methods.