mushroom cultivation (2024)

Mushrooms are the fruiting bodies of a fungus, just like apples are the fruiting bodies of an apple tree. A mushroom is a kind of fungus with the Latin name of Agaricus bisporus. Other cultivated mushrooms in the Netherlands are the oyster mushroom (Pleurotus ostreatus) and the shiitake (Japanese mushroom) (Lentinula edodes).

In the vegetable kingdom the mushroom is ranked with the heterotrophic organisms (lower plants). In contrast to the higher, green plants, these heterotrophs are not capable of photosynthesis. Fungi are the scavengers of nature. In mushroom cultivation too, waste products such as chicken manure, horse manure, straw, gypsum and waste water (from their own composting) are used to produce a high-quality substrate from which the mushrooms will grow. Ammonia is removed by means of an ammonia washer from the process air before it is returned to nature. Even the ammonia from the air is used as a source of nitrogen in composting. The fungus, also called mycelium, uses the compost as a source of energy for its combustion, in which energy is released that is used for growth.

Mushrooms are good for your health. They contain few calories, but are rich in fibres, vitamins and minerals. In the table below states the nutritional value per 100 grams of mushrooms in comparison with vegetables.

Nutritional value of mushrooms

Mushrooms contain an extra amount of vitamins B2 and B3. These vitamins take care of the metabolism and the release of energy from carbohydrates, proteins and fats. Vitamin B2 is also necessary for a healthy skin. Folic acid is necessary for growth and the production of blood. It is one of the few vitamins of which, on average, we take in too little from our food. Potassium is necessary for a healthy blood pressure and for muscle and nerve activity. Phosphorous takes care of healthy bones and teeth and of energy metabolism. Copper is necessary for your immune system, nerves and for the synthesis of body cells. All these nutritional values occur in high concentrations in mushrooms.

Mushrooms grow on compost. The compost is produced at specialized companies. From the moment the raw materials are mixed, up to delivery of the compost to the mushroom farms. The process takes four to six weeks, depends depending on the raw materials and the system used at the Compost yard.

When the compost has been delivered at the mushroom farm, it still takes 16 to 20 days before a start can be made with mushroom harvesting. Harvesting takes place during two to three weeks. After this it is no longer cost-effective to harvest.

The phase-III-compost is transported to the farm. At the farm the cultivation room is filled with compost with a special filling machine. A cultivation room is a climate-controlled room with racks (Dutch shelf system).

During filling the compost is put in a layer of 20 cm with on top a layer of 5 cm of casing soil. This layer is pulled into the shelf system of the cultivation room. Casing soil consists of a peat mixture, mixed by a specialized company. At farms where they do phase III themselves, the compost remains in the room, but after 14-18 days, a layer of casing soil is put on the compost.

After filling the room and/or covering the compost, the mycelium starts growing from the compost into the casing soil. This process takes 4-7 days. During mycelium growth into the casing soil, the casing soil is irrigated. By irrigating during the mycelium growth phase the mycelium cannot grow to the surface of the casing soil.

After mycelium growth in the casing soil recovery growth phase takes place. This phase takes 1 to 2 days. During the recovery growth phase no irrigation takes place and a humid, warm (summer) climate is created. As a result of this climate the mycelium grows to the surface of the casing soil.

Harvesting mushrooms takes place in “flushes”.

• The first flush is picked in 3 to 5 days and yields 15 to 20 kg/m2. If the mushrooms are mechanically harvest, in the form of once-over harvesting, this yields 22 to 26 kg/m2.
• The second flush comes after about 5-7 days and yields a little less, 9-11 kg/m2 for hand-harvesting, 10-15 kg/m2 for mechanical harvesting.
• The third flight at most yields 10-15% of production and is of lower quality, because diseases and pests are increasing very strongly. Depending on the economic situation, a third flush is harvested. It takes about 6 to 8 days before the third flush can be harvested. During hand-picking the flush is harvested in 2 days.

Total production is between 27 and 35 kg/m2. Hand-picking mushrooms can be stored and consumed fresh. Mechanically harvested mushrooms are harvested in a once-over operation and directly processed and preserved.