Want to learn about growing Shiitake mushrooms at home? This article will step you through the stages of growing a ready-made Shiitake block.
Are Shiitake mushrooms easy to grow?
They are fairly easy if you are using a pre-inoculated Shiitake grow kit. For our grow blocks, we have tried to make it as easy and fast as possible. If starting from scratch it can be challenging.
We grow several different varieties of Shiitake, including the native Lentinula novae-zelandiae in addition to a Chinese strain which has dark caps, and a Japanese variety that has a lighter cap and very full fruit body.
We usually send the shiitake block in an advanced state of maturity. So, it will be close to growing.
However, it may be in one of the 4 different phases of late maturity.
When the bag is fully colonised, the following tips will help get the mushrooms growing (pinning). We call this process ‘creating an autumn storm’. You can do this to get a new block going. It will also kick a dormant block back into gear.
The shiitake can sense impact, which would usually be after the tree or branch has fallen during a storm. It is thought that this may be a signal to the Shiitake that it needs to propagate (grow mushrooms). This technique is used to initiate first pinning, but may also help if it has been dormant for a while.
In nature, the Shiitake grows in northern (cold) latitudes and will fruit in the autumn (and spring). It will detect the fluctuation of seasonal temperature. You would typically use the refrigerator, or an ice bath, if it hasn’t fruited in a couple of weeks, and the weather has been warm (say +23c).
Shiitake are very cold tolerant, often spending winter in a frozen log. Unfortunately, this means that many growers of Shiitake import frozen blocks from China and fruit them in NZ claiming that they are NZ-made. Our Shiitake is 100% NZ made, from NZ products.
Soaking the block simulates an autumn rainstorm. As far as the little Shiitake is concerned, it’s dreaming of being in a puddle on the forest floor. Together with raising the temperature a couple of days later, simulates a warm sunny autumn day. The shiitake sense this and know that the forest is now a perfect humid environment to grow.
You may need to soak the block at regular intervals. Half the weight of the shiitake block is water. So if a 5kg one is weighing in at 2.5kg… there is no water left. So if it’s getting close to 3kg it needs a soak. Tap water (with Chlorine etc) is fine.
After the block is made, the shiitake mycelium will slowly grow through the substrate. After about 6 weeks, the patches of white will thicken and slowly spread and eventually cover the surface of the entire block. After about 3 months it should appear thicker and have a velvety texture.
It’s easier to demonstrate this as visually. It looks almost like the Shiitake block is going through an exceedingly slow-motion boil. It’s typical that this stage happens before the browning stage, but it may happen after.
At this stage, some people may spray the white mycelium off using a high-pressure hose. This can speed up the browning.
I find this the most wonderful stage. What we are seeing is the shiitake developing skin. Much like our own skin, this will protect it from the outside environment (from other fungi like yeasts or moulds, and bacteria). The skin is formed by liquid metabolites. You will see this under the plastic as a brown liquid. These metabolites are the Shiitake’s very potent immune system in action. These same metabolites are also in the mushrooms themselves when it grow. They are then bio-available to our own bodies, so we inherit them and boost our own immune system.
Eventually, some of the popcorning lumps will have a dark centre and grow into a baby shiitake. Once it starts to pin it requires less attention than Oyster mushrooms. As long as its in an area that’s not overly dry it should continue to grow. If it’s inside mist it several times a day, if outside you can just spray it with a hose.
Here are some of the most frequent questions people ask about how to grow shiitake mushrooms at home. If there’s something missing please let us know using the live chat feature on our website.
The size will influence overall yield, but It’s hard to predict in kilograms, here is a rough guide
Being nature and your own unique growing environment, it’s impossible to predict. Typically it takes about 18 weeks after we make it. This date is part of the batch number on the side of the bag. We then incubate it for about 12 weeks in our lab, so you still have several weeks to wait. However, the shiitake will respond well to your patience and general good vibes.
If you care for it, it should produce for over 12 months. If you are really good, closer to 24. However, it’s nature and there are a lot of variables that will affect its longevity. As it gets older its yield will decrease as nutrition is depleted. When you think it’s finally done, you can use it as mulch in the garden.
It should cycle on and off fruiting every couple of weeks. Sometimes you may have the odd shroom popping up randomly, but if you have it in a good environment it should have a fairly consistent cycle, producing over a half-dozen mushrooms at a time. This is followed by several weeks of being dormant. If it has been dormant for over a month, try to initiate pinning by performing the autumn storm technique.
We sell our shiitake blocks as mature, so they are generally ready to go. We have taken out the long wait and made success more certain. Others sell kits or logs. Kits may require you to find a suitable stump or log (usually a deciduous Harwood, like oak or Hickory, drill your own holes, seal with beeswax and wait… It may take over a year for anything to happen if anything happens at all. Some people want to manage and be part of the entire process, others just want to eat them.
We do not grow on logs because it’s a very slow process, and has a lower success rate. Instead, our Shiitake substrate recipe uses a combination of organic pine sawdust, plus some wheat bran for added nutrition plus water.
As the shiitake mycelium colonises the substrate it binds the loose sawdust into a fairly solid block and gains a texture similar to cork.
Shiitake require less care than Oyster mushrooms when it is fruiting. So it should be okay in any spot as long as it’s out of direct sunlight and drafts. They are more tolerant of being grown in sheds or garages, or outside in a shelter or damp location. However, beware of pests like mushroom gnats and slugs.
If you have an air conditioning/heat pump, be aware that this will dry the air. Please try and maintain a humid environment. Here’s an article about where to grow mushrooms
This is considered a desirable quality especially if you are considering drying them for storage. This happens when the fruit body is moistened (misted etc) and you then let them dry out, as the cap grows. If you don’t want this happening then keep the cap moistened.
You can play around with the humidity and try to get the caps to split. Go for the perfect ‘hana donko’ grade shiitake. Or you can go minimal and simply watch them grow while you write your haiku.
The perfect shiitake are picked soon after the cap separates from the stem, and starts to expose its gills. If you want a larger shiitake you can leave it a day or so to grow. If you leave it longer the cap will flatten out and drop spore. Try to avoid this. The Shiitake mushroom growing time is about 6-7 days.
Our general rule of thumb: If you are comfortable, they will be comfortable. But, Shiitake prefer running it a little cooler. They may go dormant in the summer months, so if you are wanting to increase production you will need to cool them by putting them in the fridge. The ideal shiitake mushroom growing temperature is between 12 and 18 degrees Celsius.
Sometimes the fruit bodies will be small, but larger on the next flush. You may get smaller fruit bodies after soaking or when many are growing at the same time.
Shiitake are very hardy, and it’s likely that it’s okay. Soak it in water to rehydrate. It may bounce back quickly or may be dormant for a while. Be patient. Be careful not to oversoak it. This may damage the mycelium and encourage mould. The weight of the block, after soaking, should not be more than the original weight when you brought it.
If too dry the surface of the block may split or crack.
These types of mushrooms grow in the deep shade of the forest, so inside room lighting is about right. It doesn’t need light to grow, so it is equally ok in the dark. I prefer to give it a natural environment, as possible, to stimulate the production of micronutrients.
You can, but it’s likely that pests like fungus gnats will make a home of it and get to your mushrooms first. The larvae stage of the gnat lives inside the farm eating the mycelium and weakening it. They will eventually eat their way through the cap and fly away to lay more eggs. If you see little critters flying around your shiitake block, invest in some yellow sticky fly traps sold in garden centres.
Also, protect it from getting too wet, so rain etc as this may damage it.
Because we sell our Shiitake grow kits at a mature stage. There’s very little risk of a major mould outbreak. However, If the shiitake farm is too damp, after the soak, sometimes mould may appear. Often the shiitake can fight back and deal with it. If it’s struggling or looks like it’s getting worse, try dabbing some hydrogen peroxide on the mould. At worst, you may need to carve off the affected part out.
If you forgot and left it soaking for a few days, just let it drain and recover. It should be ok, but watch out for mould. The mycelium may have weakened so be careful in handling it. In extreme cases, the mycelium may have been permanently damaged and will quickly deteriorate and die.
Oyster mushrooms are very aggressive growers. It takes them 3 weeks (after making a bag) to fruit but the Shiitake needs 3 months. As a consequence, the oyster mini-farms are usually ’spent’ after 3 months whereas Shiitake can go 6+. Being aggressive the oysters will often have very large flushes or yields, whereas the Shiitake is less, but spread over a longer time.
Another main difference is that we remove the bag from the Shiitake but leave it on for the Oysters. This is because the Shiitake grows a protective skin, and the Oyster doesn’t.
They also require less humidity and care while the mushrooms are growing. The main challenge is getting them to fruit in the first place.
Unfortunately, we have not found a suitable substitute for the polyethene bags, but we are working on it. We are also very sceptical regarding the biodegradable nature of plastic alternatives (biodegradable plastics are almost an oxymoron).
If you cannot dispose of the plastic ethically please send it back to us. On the farm, we melt these plastics down into bricks that are used as edging etc in the garden. This way we can manage the waste by turning it into a somewhat solution. We are also acting as custodians of our waste until such time as it can be more effectively processed.
We are also in a good position and interested to experiment with strains of Oyster mushrooms that are being developed to digest plastic. Watch this space.
How to grow Shiitake Mushrooms, the University of Vermont
Grow cycles guide how to grow shiitake
We sell our shiitake blocks as fully mature, so takes up to 4 months to prepare. Because they are very popular we are often sold out.