How to grow your own Shiitake Mushrooms

Updated: Dec 21, 2021

Shiitake mushrooms (Lentinula edodes) are a common edible mushroom native to East Asia. They grow in clusters on decaying deciduous hardwood trees/logs/stumps and have been used widely in traditional medicine, as well as a staple ingredient in many Asian dishes for centuries. Shiitake are now cultivated worldwide, making up about 25% of the total production of mushrooms globally.

Growing shiitake mushrooms can be done commercially for profit or in a household, hobby setting. We offer everything you need to grow your own shiitake mushrooms at home, or in the garden, in New Zealand: from spawn, to dowel spawn for making your own mushroom logs, to pre-colonised shiitake blocks that are ready to fruit!

Benefits of consuming shiitake - Shiitake mushrooms can help boost the immune system, fight cancers and support healthy heart function by lowering cholesterol levels. Shiitake are low in calories, high in fibre and offer a generous amount of B vitamins. When sun-dried with the gills up, shiitake mushrooms can take up to 10,000 x's the daily dose of vitamin D!

Growing Shiitake Mushrooms on logs in your NZ garden

An easy, low maintenance way to grow shiitake mushrooms is to use 'dowel spawn' to inoculate logs. Mushroom logs are a bit more of a long-term option and can take anywhere for 6 months to a few years to start producing mushrooms depending on the size of the log. Once colonised, the bigger the log, the longer the log will produce mushrooms and can keep producing mushrooms every year for several years!!

For more information about growing mushrooms on logs, check out our blog post here on the theme.

Growing Shiitake Mushrooms on sawdust fruiting blocks

Growing shiitake mushrooms on blocks is a more short-term option than growing on logs. Some of you will be making your own shiitake blocks from spawn, while others may be getting a shiitake block that is ready to 'fruit' or start producing mushrooms. If you have received a shiitake block that is 'ready to fruit' and already brown, you have skipped to Stage 4 - "Pinning and Fruiting."

The 4-stage life-cycle of the shiitake fruiting block

Stage 1 "Colonising"- You have mixed your shiitake spawn with sterile substrate, now the block is colonising and held together by white mycelium. The block is made up of sterilised sawdust and bran inside a special filter-patch-bag which allows air exchange while keeping a sterile environment inside the bag. Leave the block in the plastic bag until stage 3 is complete.

Stage 2 "Popcorning"- The block begins to ‘popcorn’ forming bulbous knots, bumps and blisters all over it. Once the 'popcorning' process starts, avoid handling the block as much as possible. The block is now essentially shock-sensitive, as, in nature, shiitake mushrooms will commonly fruit after the tree that they are growing on falls and impacts the ground. Touching, moving, or handling the block during this stage can induce premature fruiting, which will reduce mushroom yield. If the block does begin to produce mushrooms under the plastic the bag will need to be removed and move to "Stage 4 - Fruiting/ Mushroom Production Time"

Stage 3 "Browning"- The surface of the block will begin to go dark brown, many first-time-shiitake-growers think that this is contamination, but it is ideal ... this is what you want to see! It is ready to fruit once the block is at least 50-70% brown. The block is now ready to be handled and produce mushrooms! This is when you remove it from the plastic bag.

Stage 4 "Pinning and Fruiting"- Fruiting/ Mushroom Production! Remove the plastic bag by cutting with a clean razor, it is not a problem if you cut the block a little. Spray water directly on the block until dripping wet morning and night for 2-3 days until you start seeing little mushrooms appear. You can stop spraying when the mushrooms begin appearing on the block.

Finding a good spot for your shiitake block!

As stated above, once the block starts to popcorn, it shouldn’t be disturbed until it is ready to fruit. Finding a spot where the kids or family pets won’t knock it over during this stage is essential. Bathroom and high kitchen benches are usually ideal, but anywhere out of direct sunlight will do. If you have a busy household, potentially above the fridge will be a perfect spot! (Just remember to put an alarm in your calendar to check on it after 40-50 days). The blocks are normally ready to fruit 50-70 days from the date on the bag.

How many times will the block fruit?

In a perfect environment, the block will fruit up to 5 times before using up all of its available nutrients. However, in a non-sterile setting such as the house, it may fruit only a few times before getting contaminated with foreign moulds (usually green-mould, like on your bread). At this point you can put it out in your garden, out of direct sunlight, to continue fruiting. Once the block is used up and no longer producing mushrooms, you can put the entire block in the compost or disperse it anywhere in the garden.

Harvesting - Shiitake mushrooms are ready to harvest as soon as you can see the gills underneath. Harvest by cutting the stem off as close to block as possible. Fresh shiitakes will last in the fridge for up to two weeks.

Successive fruiting - Once you have harvested all the mushrooms off the block initially, leave the block to rest and dry for 2 weeks. To induce the second fruiting, submerge the block completely under cold water for 6-12 hours. Remove the block very carefully from the water and sit to allow it to drain. Block will be soft, heavy and fragile until the water drains back out of it. Once it has drained enough, put back it in your chosen spot for growing.

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