Preparation of Mushroom Growing Substrates - North American Mycological Association (2024)

FAQs

What are the substrates used for mushroom cultivation? ›

Substrate prepared specifically for growing mushrooms is a blend of natural products. Common ingredients are wheat straw bedding containing horse manure, hay, corn cobs, cottonseed hulls, poultry manure, brewer's grain, cottonseed meal, cocoa bean hulls and gypsum.

It essentially involves preparation of pure culture of mushroom from tissue/spores, evaluation of selected cultures for yield, quality and other desirable traits, maintenance of selected cultures on suitable agar medium, followed by culturing on sterilized grains and further multiplication on grains.

An effective pasteurization will eradicate harmful bacteria, nematodes, insects and fungi. In general a compost substrate temperature of 140° F for 4 hours is adequate for a complete pasteurization.

Colonization occurs after inoculation. This is when the mycelium will start to take over the grain that was inoculated with spores. This period usually lasts between 3 to 6 weeks depending on strain and environmental conditions. Ideal conditions for this phase are in a dark place and temperature between 72 F – 80 F.

Popular substrate supplements

The most popular supplement materials for mushrooms are bran or seed derivatives, with oat bran and wheat bran being utilised in a 5-10% dry weight ratio. A popular mix includes 18% bran and 2% gypsum, as well as the sterilised substrate.

Therefore, sterilizing these substrates becomes essential as it eradicates all living and dormant organisms and fungal spores, providing the best possible start for mushroom mycelium. However, low-nutrient substrates like straw, sugarcane bagasse, coco coir, hardwood sawdust, and cardboard only require pasteurization.

Petri plates or small glass jars such as baby food jars can be used as the media containers. Two growth media, one agar-based and one gelatin-based, can be used to culture the mycelium of oyster mushroom; they are listed below.

(m.s.l.), the best growing season is during March/April to September/October and in the lower regions from September/October to March/April. The major states in India producing this mushroom are Orissa, Karnataka, Maharashtra, Andhra Pradesh, Madhya Pradesh, West Bengal and most of the North Eastern hill states.

Cold Water Bath Pasteurization (with additives like lime, wood ash, soap, chlorine, or vinegar): Generally requires soaking the substrate for 12 to 24 hours, depending on the specific method and conditions.

Gently submerge the bag or container with the substrate into the boiling water. Maintain the water at a simmer, not a rolling boil, to keep it at around 160° F (71° C). Pasteurize the substrate for at least 1 hour. Use a thermometer to monitor the water temperature.

How do you know when mycelium is fully colonized? ›

You can tell when mycelium is fully colonized when the entire substrate (such as a jar or a bag) is covered with a dense, white, and fuzzy network of mycelial threads. There should be no visible uncolonized areas or contaminants, and the mycelium should appear healthy and vigorous.

A) lots of water dripping shows that the substrate is too wet. b) a few drops released with some pressure show that the substrate is well watered. If it is too dry then with no drops will be released with pressure.

The higher the inoculation rate or amount of spawn added to the substrate, the faster the mycelium will grow through the substrate. The substrate likely will not produce a larger amount of mushrooms, so a high inoculation rate means more money spent on spawn per pound of mushrooms.

The main nutrients are less nitrogen and more carbon so materials containing cellulose, hemicellulose and lignin (i.e., rice and wheat straw, cotton seed hulls, sawdust [SD], waste paper, leaves, and sugarcane residue) can be used as mushroom substrates [8]. Oyster mushroom can grow on a wide variety of substrate.

The hyphae use the process of extracellular digestion to digest nutrients that are then absorbed by mycelia. To grow fungi, it is important to have the proper organic substrate such as hardwood or straw. Moisture is essential for the growth of any fungus.

The substrate on which button mushroom grows is mainly prepared from a mixture of plant wastes (cereal straw/ sugarcane bagasse etc.), salts (urea , superphosphate / gypsum etc), supplements (rice bran/ wheat bran) and water. In order to produce 1 kg. of mushroom, 220 g. of dry substrate materials are required.