Mushroom Cultivation: A Step-By-Step Guide

Mushroom Cultivation: A Step-By-Step Guide

Cultivating mushrooms may seem mysterious, but it’s actually fairly simple. Whether you are a small-scale hobbyist at home or mushroom farming in a large-scale commercial operation, it’s the same basic process. We’ll guide you step by step through how to cultivate mushrooms.

Introduction

Fungi are fascinating organisms, and the mushrooms that many species of fungus produce have a variety of uses for humans, from the button mushroom you find in grocery stores and species prized in traditional medicine, to mushrooms used for lab work in agricultural sciences and mycology research. They’re delicious, high in important nutrients like folic acid, and many species possess a wide variety of health benefits. Mushrooms may also be key to solving a number of environmental issues, from cleaning soil pollution to providing the raw materials of sustainable housing.

But how do you actually grow mushrooms? How do you start your own mushroom farm? The answer is simpler than you think! 

Mushroom Cultivation - An Overview

Mushroom-producing fungi come in a wide variety of shapes and sizes, and depending on the species, require different environmental conditions and nutrients to thrive. But the process of growing mushrooms is much the same for all of them, and can be broken down into a few simple steps. With a little preparation, you can cultivate virtually any type of mushroom at home!

We’ll take you through the steps in greater detail below, but the basic steps are largely similar, whether you are running a small scale grow room or a mushroom farm. Start with spores that have been prepared under laboratory conditions, and cultivate those in a sterile growing medium to propagate mushroom spawn, also called mycelium. These fibrous tendrils of mycelium reach out to absorb nutrients, and when you introduce them into grain, will quickly colonize everything within reach. Once the grain is fully colonized with mycelium, you’ll evenly mix it into a larger quantity of substrate, which will give the mycelium the nutrition it needs to grow and produce healthy mushrooms.

Step 1 - Culturing Mushroom Spawn

Culturing is the process of isolating and growing spores in a controlled environment.

Choosing a Culture Medium

Everything starts with the mushroom spores. Culturing is the process of using a growth medium to nurture microscopic spores into mycelial spawn.

To ensure quality and prevent contamination, most mushroom cultivators start with spores which have been prepared under laboratory conditions. This can take a variety of forms, from spores in a sterile agar plate to liquid culture or a spore syringe. Take some time to research the kind of mushroom you want to grow, what it needs to thrive, and assess your growing space. Many factors may influence which method you use for culturing.

Agar Plate, Spore Syringe and Liquid Culture

An agar plate is a petri dish with sterilized nutrients for the spores. Transferring from agar plates takes some meticulous attention to sterility, but can allow for rapid multiplication and is ideal for lab work. A spore syringe is drawn from the many spores of a single mushroom, whereas liquid culture contains cloned copies of the same single spore. Liquid culture is a better approach for consistent results, ideal for mushroom farming. But if you want to, for example, select for particular qualities, a spore syringe offers more genetic diversity to work with. Depending on your needs, any of these approaches may be useful.

Step 2 - Substrate & Grain Preparation

Bulk Substrate: The final sterilized substrate, typically wood-based or enriched with manure, that is to be inoculated with the mycelial spawn.

Pick a Substrate

Be sure to use the correct food source for your mushroom - Some species prefer wood-based substrates (including gourmet mushrooms like shiitake mushrooms and medicinal species like oyster mushrooms), while others thrive on manure-based substrates or even coffee grounds. Most common substrates are usually formulated with either wood-loving or dung-loving mushroom species in mind, since many of the varieties people want to grow fall into one of those two categories.

Wood-based Substrates

Wood-based substrates often consist of wood chips from hardwood trees, sawdust and added nutrients. In some cases, wood-loving mushrooms can even be grown by drilling holes in prepared logs and inoculating them with your choice of mycelium. Many prized species of edible mushrooms, from morel & shiitake to lion’s mane, thrive on hardwood.

Dung-loving substrates

Manure-based substrates are usually made using horse manure or chicken manure, along with straw and a mixture of other nutritional ingredients like nitrogen supplements and gypsum to aid healthy and rapid growth. Some edible mushrooms like portobello and crimini mushrooms, as well as several varieties of active fungus, fall into the dung-loving category.

Step 3 - InoculationA person in a black t-shirt giving a thumbs up while holding a syringe over the self-healing injection port of the grain spawn bag, ready for inoculation.

What is inoculation?

Inoculation: The act of introducing a mushroom culture into a sterile grain.

Procedure

Under sterile conditions, use your liquid culture or colonized agar to inoculate sterilized grains (often wheat bran, rye or something similar) with mushroom mycelium. Make sure to wear gloves and sterilize any instruments between use.

Step 4 - Grain Colonization

Grain Colonization: The mycelium will eagerly grow and expand to colonize each individual grain, making it easy to evenly distribute throughout the substrate later.

Procedure

Place inoculated grain in a dark place, ideally at a temperature between 70-78* F, and monitor for signs of growth or contamination for about 10-14 days until fully colonized.

Step 5 - Spawn-to-Bulk

Spawn is the fully colonized grain that will be used to inoculate bulk substrate. Spawn-to-Bulk is the process of mixing the colonized spawn with a bulk substrate.

Procedure

  1. Break apart the colonized grain spawn and mix it evenly throughout your bulk substrate in a mushroom grow bag or monotub.
  2. Reseal your grow bag or place the lid on your monotub to begin colonization of the substrate.

Step 6 - Substrate Colonization

Substrate Colonization: The phase in which the fungal mycelium expands from the grain spawn to grow throughout the substrate.

Procedure

Place the inoculated bulk substrate container or plastic bag in a controlled environment and regularly check for signs of mycelial growth and potential contamination (like green mold or bacteria).

Step 7 - Fruiting

Fruiting: The stage in which the mycelium produces fruiting bodies, commonly known as mushrooms 🍄

Fruiting Conditions

Environmental conditions like temperature, relative humidity levels, carbon dioxide, and fresh air exchange are crucial for the development of primordia, also known as pins, which will mature into the fruiting stage. High humidity, cooler temperatures, and proper air flow help drive mushroom development.

Procedure For Monotubs

Remove coverings or plugs from lid holes and apply filters to promote air exchange and create ideal fruiting conditions.

Procedure For Bags

Expose the bulk substrate to fruiting conditions by opening the bag or cutting a hole or slit.

Step 8 - Harvest

Procedure

When the mushrooms have fully matured, carefully separate from the substrate using a knife, or twist and pull at the base to remove. Enjoy your mushrooms!

Pro tip: Timing

Be sure to research ideal harvesting times for each species you grow in order to harvest at peak maturity. Waiting too long to harvest will cause your mushrooms to release spores.

Flushes

Under ideal conditions, mushrooms will repeat the production of fruiting bodies again after harvesting. Each new development of mushrooms in a grow is known as a flush. Some strains of mushroom may develop two, three or even more flushes before the substrate runs out of energy.

Conclusion

While the details of each step may vary based on the species of mushroom you cultivate, the basic process of mushroom growing is the same. Do your research beforehand and carefully create the ideal conditions for your crop, then follow these steps to successfully grow your own mushrooms any time!