MUSHROOM PRODUCTION BHT310

Learn about growing, harvesting, marketing, storage, pest and diseases and even ways of cooking and using mushrooms.

There are thousands of different fungi which have at some stage or other through history been tried as a food by some group of people. Obviously, some people have been poisoned at times in the process of working out what is and what is not edible.

It is the fruiting bodies (called "Sporocarps") from the more advanced (ie: complex) types of fungi which are eaten. Some of these sporocarps are deadly poisonous, so be careful not to eat anything which is not first accurately identified. All edible fungi fall into either the "Ascomycetes" or "Basidiomycetes".

While the Agaricus species (Champignon) is the main focus of this course, other commercially important edible fungi (eg. Straw mushroom, Oyster Mushroom, Shiitake, etc) are also studied as a foundation for any scale of serious production.

Lesson Structure

There are 8 lessons in this course:

1. Introduction
   • How Fungi are Named: Review of the system of plant identification
   • Characteristics of all Fungi
   • Three Fungi Kingdoms: Zygomycota, Basidiomycota, and Ascomycota
   • Agaricus campestris and Agaricus bisporus
   • Review of significant edible fungi including; Coprinus fimetaris, Flammulina velutipes, Letinus erodes, Pleurotus, Stropharia, Volvariella,Auricularia auricula
   • Synonymous Names
   • Distinguishing edible fungi, Mushroom structure, telltale characteristics of the genus Agaricus, etc.
   • History of Mushroom Cultivation
   • Commonly Cultivated Edible Fungi
   • Agaricus bisporus, Agaricus bitorquis
   • Coprinus fimetarius
   • Flammulina velutipes
   • Kuehneromyces mutabilis
   • Lentinus edodes Shiitake.
   • Pholiota nameko
   • Pleurotus spp "Oyster Mushroom"
   • Stropharia rugosa annulata
   • Volvariella volvaceae Edible Straw Mushroom.
   • Auricularia spp
   • Tremella fuciformis
   • Tuber spp.
   • Tricholoma matsutake
   • Ganoderma lucidum (Reishi)
   • Grifola frondosa (Hen of the woods, Maitake)
   • Resources, information/contacts
2. Mushroom Culture
   • Options for obtaining Spawn
   • Steps in Growing Agaricus species: Preparation, spawning, casing, harvest
   • What to Grow Mushrooms in; growing medium
   • Growing media for different edible fungi: Agaricus, Auricularia, Coprinus, Flammulina, Letinus, Pleurotus, Volvariella, etc
   • Understanding Soil and Compost, components and characteristics
   • Acidity and Alkalinity
   • Making Compost
   • Making Mushroom Compost, and mushroom compost formulations
   • Moisture Level in Compost
   • Cultivation of Agaricus bitorquis
   • Cultivation of Coprinus fimetarius
3. Spawn Production and Spawning
   • Finding Spawn Supplies
   • Overview of Spawn and Spawning
   • Obtaining Smaller Quantities of Spawn
   • The Process of Spawning
   • Spawn Production; typical rye grain method
   • Storing spawn
   • Problems with Spawn
   • Using Spawn
   • Comparing temperature conditions for spawning and fruiting in most commonly cultivated edible mushroom species
   • Cultivation of Pleurotus
   • Cultivation of Stropharia
4. Making and Casing Beds
   • Growing Methods; Caves, bags, houses, outdoor ridge beds, troughs, etc
   • Casing; biological process, characteristics of casing material, procedure
   • Techniques; spawned casing, ruffling, scratching
   • Review Auricularia and Volvariella
5. Growing Conditions for Mushrooms
   • Fungi Nutrition: carbon, nitrogen, essential elements, vitamins and growth factors
   • Casing to Harvest of Agaricus
   • Growing Indoors
   • Components of a Built System and Determining Your Needs
   • Factors Influencing Fungal Growth
   • Environmental Control, equipment to measure and control the environment
   • Siting a Growing House
   • Managing the Growing House or Room, cleanliness, heating, cooling, humidity, etc
   • Review of Tuber (Truffle) and Tremella
6. Pests, Diseases and Growing Mushrooms Outside
   • Overview of Pests, Diseases and Environmental Disorders
   • Prevention of Problems
   • Review of Bacterial and Fungal Diseases and their Control
   • Review of Insect Pests, Mites, Nematodes and their Control
   • Weed Moulds
   • Safe, Natural Sprays
   • Summary of Problems found on Agaricus bisporus and other edible fungi covered in this course
   • Cultivation of Flammulina velutipes and Kuehneromyces mutabilis
7. Harvesting, Storing and Using Mushrooms
   • Harvesting Buttons, Cups and Flats on Agaricus bisporus
   • Fruiting patterns for Agaricus bisporus and other edible mushrooms
   • Cool Storage of Mushrooms
   • Freezing Mushrooms
   • Dry Freezing Mushrooms
   • Drying Mushrooms
   • Canning Mushrooms
   • Harvesting Agaricus; method of picking
   • Handling Agaricus after harvest
   • Controlled Atmosphere Storage
   • Cultivation of Letinus (Shiitake), Pholiota, Tricholoma
8. Marketing of Mushrooms and Special Assignment
   • Review of Marketing options for mushrooms
   • Fresh Mushroom Sales
   • Processed Mushroom Sales
   • Production and Marketing of Shiitake, Oyster Mushroom and Straw Mushroom
   • Research and Determination of Marketing Opportunities and Strategies in Your Region

Aims

• Classify different varieties of fungi which are commonly eaten
• Determine the techniques used in the culture of edible mushrooms
• Explain the harvesting of a mushroom crop
• Explain the post-harvest treatment of a mushroom crop
• Explain marketing strategies for mushrooms

What You Will Do

• Compare the scientific with common definitions for a “Mushroom”
• Explain the classification, to genus level, often different commercially grown edible fungi
• Produce a labeled illustration of the morphological characteristics which are common to different edible fungi of the genus “Agaricus”
• Compare the physical characteristics of different commercially cultivated edible fungi
• Distinguish edible Agaricus mushrooms from similar, inedible fungal fruiting bodies
• Compile a resource file of sources of information regarding edible fungi, including: *Publication *Suppliers *Industry associations/services
• Determine the preferred conditions for growing two different specified mushroom genera
• Describe the stages in the growing of Agaricus mushrooms
• Develop criteria for selecting growing media, for two different genera of edible fungi; including Agaricus
• Describe an appropriate compost for growing of Agaricus bisporus
• Explain how spawn is produced for two different genera of edible fungi
• Explain the use of casing in mushroom production
• Compare different methods of growing edible fungi, including where appropriate: *Outdoor beds *In Caves *In buildings *In trays *In bags *In troughs
• Describe different pests and diseases that affect mushrooms
• Describe appropriate control methods for ten different pests and diseases of mushrooms
• Analyse hygiene and exclusion regimes used in mushroom production
• Prepare a production plan, based on supplied specifications, for Agaricus bisporus, including: *Materials required *Equipment required *Work schedule *Cost estimates
• Grow a crop of Agaricus bisporus
• Identify the stages at which Agaricus mushrooms can be harvested
• Explain how mushrooms are harvested
• Develop guidelines to minimise damage to different types of mushrooms, during and immediately after harvest
• Describe ways to extend the shelf life of two different mushrooms crops
• Explain three different techniques for processing mushrooms
• Produce dried mushrooms from fresh ones
• Analyse industry guidelines for the post-harvest handling of a specified mushroom variety
• Determine the different ways mushrooms are packed for retailing
• Outline industry generic marketing strategies for mushrooms
• Suggest strategies for marketing a separately identified mushroom product (e.g. branded, regional)

Lentinus edodes (Shiitake)

Agaricus bisporus is the Most Popular Mushroom

Spawn

The most difficult part to grow yourself is the spawn (although, specialist suppliers can provide spawn from laboratories). Most commercial farms may not even worry about producing their own spawn, but some do.

Nowadays, grain spawn is used predominantly for growing mushrooms. Grain spawn ‘runs’ more quickly, allowing mushrooms to grow a week earlier than when using manure spawn, saving time in planting. Grain spawn is produced by growing mushroom mycelium on sterile cereal grains. Rye and millet are commonly preferred. Rye grain spawn is typically made as follows: The grain is boiled in water to increase the moisture content. A hard grain type is best used to avoid bursting of grains during boiling. Water is drained off. The grain is then mixed with gypsum (calcium carbonate), 2% by weight, and powdered chalk (calcium carbonate), 0.5% by weight. This prevents grains from sticking together. The grain is then filled into containers and autoclaved at 121 °C for 1.5 to 2 hours and 15 psi. Upon cooling, the grain is inoculated with mycelium. A temperature of 25 °C is maintained while the mycelium grows through the grain. It takes 11-14 days for the mycelium to colonise the grain. The grain is usually shaken twice to achieve rapid and even colonisation.

Tobacco spawn is another type of spawn that can be used to grow mushrooms. Pulverised tobacco stems act as the carrier. Tobacco spawn is believed to have some advantages, such as increased aeration (due to the porous nature of the tobacco stems), which promotes maximum growth of the spawn.

Spawns are classified based on cap colour and the proneness of the cap to develop scales. There are four basic types of A. bisporus spawn: smooth or pure white, rough or off-white, cream and brown. Further sub-divisions can be made based on e.g. the size of the mushrooms.

How to Grow

There are four key stages in the growing of mushrooms:

Stage 1: Preparation
First, you need to acquire some spawn. This is like seed and will germinate to grow into the mushroom plant. You can purchase spawn in sealed containers or if you buy a pre-packaged mushroom kit the spawn may already be planted in the compost. A bed or container is filled with compost suitable for growing mushrooms in. The compost must be very rich, usually containing a lot of well-rotted animal manure.

Stage 2: Spawning
The spawn is removed from the sealed jar and broken up into 1cm diameter pieces. Plant the spawn about 2cm deep and 25cm apart. Keep moist, but not saturated. Light is not needed but cool, dry, draught-free conditions are required if production is to be good. The ideal temperature during this stage is between 22 and 25°C. If temperatures are lower, growth will be slower. High humidity is also preferable. Because of these requirements, mushrooms are frequently grown in a shed or under the house. Growing trays can be stacked on shelves to save space.

Stage 3: Casing
Casing involves covering the compost with an inert, protective layer of moist material like peat or vermiculite. Mineral supplements such as gypsum, hydrated lime, and often crushed oyster shells are added. The most common material used is a mix of peat moss and lime or coir fibre and lime. The casing protects the substrate and holds in moisture which induces fruiting and mushroom development. Casing may be applied a couple of days after planting through to several weeks, temperature should be lower at about 15°C.

Stage 4: Harvest
The first mushrooms should be ready to harvest between 6 and 10 weeks after planting. The crop appears in flushes. Normally each flush is harvested over 3 to 4 days.  The bed is then left a couple of weeks, and a second flush will appear. Flushes may continue for months, or taper off within weeks depending on conditions. Mushrooms can develop quickly once they appear. Once ready for picking, they must be picked. Delaying picking by just 24 hours can result in significant deterioration.

Growing Tips

- Vermiculite makes a great casing material - it is cheap, totally inert and can hold up to 16 times its weight in water.
- Peat moss is an acidic material that is also commonly used for casing, but you need to add lime to bring up the pH from neutral to slightly alkaline (pH 7.5 to 8.5 is ideal).
- Coir fibre is an environmentally friendly alternative to peat which is made from the shells of coconut husks. It is very water retentive and also adds nutrition.
- Avoid using coir as the bulk substrate because it encourages the growth of mycelium over the casing layer.
- You can use a mixed casing e.g. 50:50 coir to vermiculite.
- An ideal casing mix is 40:40 peat moss to vermiculite with added agricultural hydrated lime (5%) and crushed oyster shells (15%).
- Fresh air and evenness of temperature and humidity are important. Mushrooms will probably crop without it, but will benefit from a fan being placed in the room with them after casing. Low watt fans can be run almost 24 hours a day for a few weeks with little impact on your electricity bill.

Pests and Diseases

There are few pests to look out for. Chief amongst these are springtails, millipedes and slaters which are attracted to the compost. They only cause significant damage if their numbers are large. Nematodes may be present in peat and these can cause mushrooms to become mushy. The larvae of some small flies may also burrow into mushrooms.  Some species of mite cause pitting of stems and caps.  

Mushrooms are prone to a number of fungal diseases including several moulds, mildew, damping off and brown spot. Another one is a fungus called Diehlomyces which competes with mushrooms. It is commonly called Calves Brains due to its furrowed shape. All pest and disease problems can be limited by good hygiene practices. Some fungicides and pesticides are permitted for use on mushrooms but you need to check with mushroom growers associations.    

Why study this course?

Learn how to grow a variety of Mushrooms for home, or on a commercial scale. Understand the requirements for growing mushrooms, their cultural requirements, growing indoors and outside, and growing them in the appropriate media.