About commercial mushroom growing
Welcome to the world of mushroom cultivation! Whether you’re a curious newcomer or a seasoned grower, our association is here to support your journey in this fascinating and rapidly growing industry.
The production of specialty mushrooms is a process that can be divided into three phases:
- Spawn production
- Substrate production
- Cultivation of the mushrooms
In Europe, companies are normally specialised in one of the three phases.
Spawn production is only for highly specialised companies with a high level of knowledge and equipment.
Substrate preparation
1. Selecting raw materials
Depending on the type of mushroom, suitable raw materials are used (e.g. sawdust, straw and nutrients in the form of maize, sunflowers, oil seed cake, etc.). These are mixed, filled into bags and sanitised.
- The raw materials are moistened and thoroughly mixed before being sanitised. There are four possible methods for this:
- Filling into bags with filters and autoclaving at 121 °C.
- Filling into bags with filters and heating at 100 °C in a room for a long time.
- Filling into a bulk mixer, sterilising by introducing steam for 4–10 hours, then inoculating after cooling and filling into bags.
- Pasteurising the substrate in a tunnel at 70 °C (usually for Pleurotus or Shiitake). After cooling, the substrate is inoculated and filled into bags.
The substrates are stored in bags with filters so that the mushrooms always receive sufficient oxygen without risk of infections.
Substrate preparation
2. Growing and maturing
The inoculated substrate must first grow through and mature completely before it can be used for cultivation.
It should be noted that mushrooms need oxygen and produce heat during growth. Therefore, the substrate bags must be separated from each other, and good air circulation is important to dissipate the heat. Temperatures above 30 °C in the substrate are lethal.
3. Summary of substrate preparation
- Space for storing raw materials
- A mixing and filling plant for the substrate
- Facilities for sterilisation or pasteurisation and rooms where the substrate can mature
- Please note: Some fungi (e.g. shiitake) need light to mature, while others need darkness – otherwise fruiting will be triggered too early.
- Sterilisation and inoculation of the substrate require absolute cleanliness in order to minimise the high risk of infection.
Cultivation
The cultivation of mushrooms involves the following steps:
a) Initiating fruiting
The matured substrate blocks are brought to fruiting. Important influencing factors are light, temperature, CO₂ or oxygen content and humidity
b) Harvesting
Depending on the type of mushroom, harvesting takes place in one or two flushes. This means that the duration of the harvesting cycle can vary.
c) Time frame
Depending on the growth rate, mushrooms can be ready for harvest after just 7–8 days or only after 14–15 days. One cycle lasts about two to three weeks per flush.
d) Variety selection
Cultivating different types of mushrooms in one room is usually counterproductive, as they require different rhythms and conditions.
e) Climate conditions
Mushrooms are very sensitive and require a precisely controllable climate. The temperature and humidity of the room must be adjustable. In addition, the rooms must be easily lockable and separated from each other to prevent the entry of diseases or pests (insects, mice, spores, bacteria etc.).
Summary for planning cultivation
- Selection of mushroom varieties
- Defining the room sizes according to the planned production volume
- Determining the number of rooms
- Example: Two rooms are sufficient for shiitake, three for other varieties.
- Mushrooms that form two flushes (e.g. oyster mushrooms, pioppino) can be filled within two weeks, resulting in a complete cycle in six weeks.