Growing Shiitake Mushrooms

How to grow Shiitake mushrooms

If you’re thinking of growing Shiitake mushrooms, you’ll be glad to know that as well as being delicious to eat, they’re also one of the easiest types of mushroom to grow at home.  All you need to bring to the game is the right knowledge and a little patience. This guide will take you through the process from start to finish, covering substrate recipes, spawn options, container choices, optimal growing conditions, and different Shiitake strains.

There are several strains of Shiitake mushrooms, each with their own characteristics in terms of flavour, yield, and growth habits. The most popular strains are:

Lentinula edodes (‘standard’ Shiitake):  This is the most commonly cultivated strain, prized for its robust flavour and reliable yields. Most Shiitake liquid culture sold online will be for this variant.

Donko: Also known as “winter mushrooms,” Donko Shiitakes are harvested when the caps are tightly closed, resulting in a meatier texture and stronger flavour.

Black Forest: These mushrooms are known for their dark caps and intense, smoky flavour. They are favoured by chefs for their culinary versatility.

Sawtooth Oak: Derived from wild strains, Sawtooth Oak Shiitakes are prized for their nutty flavour and firm texture.

Getting Started

Before you can start growing Shiitake mushrooms, you need to decide what type of grain spawn you want to use, what type of substrate and what you’re going to grow them in. Luckily they’re relatively simple choices.

Shiitake Spawn Choices:
By Shiitake spawn we mean the base material that you use to start growing Shiitake mycelium by inoculating it with mushroom liquid culture. Shiitake mycelium can be grown on different materials, the most popular being grain spawn and sawdust spawn. Grain spawn is normally rye, wheat or millet and is widely used because it’s easy to use. Hardwood logs can also be used, and these provide long term sustainable crops, but  require significantly more time to reach fruiting and harvesting stage.

You can buy pre-colonised Shiitake spawn or choose to create your own with purchased or home-made liquid culture.

Shiitake Substrate Choices:
Growing Shiitake mushrooms can be done on various substrates, with hardwood sawdust being the most popular. The easiest way to find hardwood sawdust for most people is to buy hardwood fuel pellets, which are widely available in DIY stores and garden centres. You can also use straw, wood chips, or a combination of these materials.

One commonly used substrate for home growers is a mix of hardwood sawdust (or pellets) mixed with wheat bran or rice bran at a ratio of 5:1. Water is added until the mixture reaches 60-65% moisture content. This mix must then be sterilised, typically by autoclaving or in a pressure cooker (15psi, 121 degrees celcius) for 90-120 minutes to kill any competing organisms.

Container Choices:
Choose sealable containers that provide good airflow and allow for moisture retention. Specialist mushroom grow bags are perfect for this as they can be sealed to prevent ingress of contamination yet have built-in filter patches to allow filtered air to enter the bag, meaning your mushrooms can still breathe.

Cultivation Process

Inoculation and incubation of spawn
To start your growing process you first need colonised spawn. Assuming you’re using sterilised grain such as rye for this it will be supplied in a sealed mushroom bag and should have some form of self-healing injection port. Inject Shiitake liquid culture through this port at about 4ml of liquid culture per 1Kg of grain. Then put the bag in a warm, dark place (24-27°c) and leave it there until the grain has been fully colonised. Ensure a stable temperature is maintained.

Inoculation of substrate
Once your grain has been fully colonised and your substrate is ready, mix the two together in a clean, sanitized environment. Distribute the spawn evenly throughout the substrate to ensure uniform colonization. Seal the container and incubate at around 24-27°c in a dark, humid space.

Colonisation
Monitor the container for signs of mycelial growth, which typically occurs within 2-4 weeks. Maintain high humidity levels (around 90%) by misting the substrate as needed. Avoid exposure to direct sunlight during this stage.

Fruiting
Once the substrate is fully colonized and covered with mycelium, initiate fruiting by exposing it to cooler temperatures (around 13-16°C) and increased air circulation. You can achieve this by transferring the substrate to a fruiting chamber or by adjusting the ambient conditions in your growing area. If you are using a plastic tub to grow your Shiitake, you can aid air exchange by opening the lid to gently fan the contents several times a day, closing the lid afterwards.

Harvesting
Shiitake mushrooms will begin to develop primordia, or pinheads, which will mature into full-sized mushrooms in 7-10 days. Harvest the mushrooms when the caps are still slightly curled under to ensure optimal flavour and texture. Twist or cut the mushrooms at the base of the stem to harvest, allowing for regrowth of additional flushes.

Growing Shiitake mushrooms on logs

Shiitake mushrooms can also be grown on hardwood logs, a method known as log cultivation. This method mimics the natural habitat of shiitake mushrooms, which often grow on dead or decaying hardwood logs in the wild. Here’s a simple guide on growing shiitake mushrooms on logs:

Log Selection:
You will need to find healthy hardwood logs from trees such as oak, beech, maple, or ironwood. Avoid softwoods. You need to harvest your logs during the period between late autumn to early spring, when the trees are dormant. Freshly cut logs are best, as they have a higher moisture content and are less likely to be contaminated with competing fungi. Choose logs that are 3 to 6 feet in length and 4 to 8 inches in diameter.

Inoculation:
Drill Holes: Using a 5/16-inch drill bit, drill holes into the logs spaced 4 to 6 inches apart in a diamond pattern. The holes should be 1 to 1.5 inches deep. Insert shiitake spawn plugs (readily available online) or sawdust spawn into the drilled holes. Gently tap the spawn plugs into the holes with a hammer until they are flush with the surface of the log. Finally, seal the spawn plugs with melted food-grade wax or cheese wax to prevent contamination and retain moisture.

Log storage and incubation:
Stack your inoculated logs in a shaded area with good airflow. Arrange them in a crisscross pattern to promote air circulation and prevent mould growth. Cover the stacked logs with a breathable material such as shade cloth or burlap to protect them from direct sunlight and excessive drying. Keep the logs moist by watering them regularly, especially during dry periods. Use a misting hose or sprinkler to maintain adequate moisture levels.

Be Patient!
Allow the spawn to colonize the logs, which typically takes 6 to 12 months, depending on environmental conditions and the type of wood used.

Fruiting:
Once the logs are fully colonized with mycelium (visible as a white, web-like growth), initiate fruiting by soaking them in cold water for 24 to 48 hours. This simulates the natural rainfall that triggers mushroom formation. After soaking, “shock” the logs by striking them against a hard surface or dropping them from a short height. This shock mimics the natural impact caused by falling branches and helps stimulate mushroom formation.

Place the soaked logs in a shaded, humid environment with good air circulation. Ideal temperatures for fruiting are between 50 and 70°F (10-21°C).

Shiitake mushrooms will begin to emerge from the inoculation points on the logs within 1 to 2 weeks after soaking. Harvest the mushrooms when they reach the desired size by twisting or cutting them at the base of the stem.

Maintenance:
After each flush of mushrooms, repeat the soaking process to encourage additional fruiting. Logs can produce mushrooms for several years, although each subsequent flush will diminish in size and frequency. Keep an eye out for pests such as slugs, snails, and insects that may feed on the mushrooms or mycelium. Remove any damaged or infested mushrooms promptly.

This is a mushroom growing guide specifically for growing Shiitake mushrooms, but we have growing guides for other mushroom species here on our mushroom growing guides page.