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Organic Shiitake Mushroom Grow Kit Fruiting Block












Skill level | Intermediate |
Grow location | Indoors |
Grow speed | 1.5 to 2 weeks |
Kit shelf life | 6 months (refrigerated) |
Kit dimensions | 6in H x 9in W x 6in D |
Kit weight | 5 lbs |
Fruiting temps | 55-70°F |
Our Shiitake (Lentinula edodes) fruiting block features a popular strain that produces light brown, medium-to-large, umbrella-shaped caps. Shiitake mushrooms are a delicious edible fungus from East Asia and their flavor is described as rich, savory, buttery, and umami. This strain tends to produce generous flushes, making them a great mushroom for confident beginners and intermediate growers.
Shiitake are reliable producers as long as the ambient humidity in the growing environment remains consistent. Because the block is removed entirely from the bag once it's ready to fruit, shiitake blocks are prone to drying out. Therefore, we recommend using a humidity tent or humidity-controlled fruiting chamber (like a monotub or martha tent) to help mitigate the moisture issue.
"5 of the Best Shiitake Mushroom Recipes"
Upon receiving your kit:
Remove kit from the shipping box as soon as possible. Then, unfold the top of the bag, making room for air space. It's also important to check and confirm that the filter patch is not obstructed. This will help the organism breathe and continue to thrive until you are ready to grow your fruiting block!
Scroll down for guides on growing, storage, cooking, and more.
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For the majority of mushroom species, all that is needed to initiate fruiting (or begin the growth cycle) is a change in environmental conditions -- specifically humidity, light, temperature, and changes to oxygen and CO2 levels.
For best results:
We recommend growing your shiitake block in a fruiting chamber (like a monotub or martha tent) as a controlled environment will decrease the risk of contamination and increase the chances of success.
Creating optimal conditions:
The environmental parameters for shiitake can be found on this page under "Temp, Humidity & CO2 guide" and on page 13 of our fruiting block instruction booklet.
Preparing your block:
Your shiitake block should be given time to brown in its bag at room temperature before fruiting is initiated.
How to initiate fruiting:
- Once the block is mostly brown, place the sealed block in the refrigerator for at least 48 hours.
- Next, remove the block from the bag and soak the block in cold water for approximately 4 hours before placing it directly into your fruiting chamber.
- DO NOT place back into the bag, as shiitake blocks grow without a bag.
Special considerations:
Shiitake can be prone to Trichoderma (green mold). If you see green mold, spray affected areas of block with hydrogen peroxide 3%.
Harvesting your mushrooms:
Harvest your shiitake block just before the caps flatten. Trim flush with the block so no stem remains on the block before subsequent fruitings. Place block back into fruiting chamber between fruitings to prevent it from drying out and to decrease risk of contamination.
Growing different blocks together:
With some compromise, many different species of mushrooms can be grown together in a fruiting chamber. First, consider the temperature range of the mushrooms you desire to grow, and second, the CO2 sensitivity. Humidity ranges overlap for the majority of species. We encourage you to experiment with many different groupings!
Troubleshooting:
Having issues with unusual growth, stunted growth, or no growth at all? Refer to pages 16-18 of our fruiting block instruction booklet.
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Temperature 55-70°F | 13-21°C Humidity (Phase 1: Primordia) 95-100% Humidity (Phase 2: Fruitbody) 85-95% CO2 Sensitivity (Phase 1: Primordia) 500-700 ppm CO2 Sensitivity (Phase 2: Fruitbody) <1,000 ppm - Primordia - The earliest recognizable stage of fruitbody development. Also known as “baby mushrooms” or “mushroom pins.”
- Fruitbody - A fully grown mushroom, the reproductive structure of the organism in which the spores are produced.
- CO2 sensitivity - When CO2 levels are too high, yields will decrease, stems will become long and stringy, caps will be small, and/or growth will halt.
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If you don't plan to use immediately, you can refrigerate your block for up to 6 months.
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"5 of the Best Shiitake Mushroom Recipes"
Shiitake has a meaty texture when cooked and is good for drying and reconstituting in winter soups. It pairs beautifully with tamari, ginger, and garlic and can bring needed umami to many different dishes. These mushrooms are delicious sauteed and can be used in stir-fries, risottos, ramens, on pizzas, or simply eaten by themselves.
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If you’re going to consume home-grown mushrooms, make sure to cook your fresh mushrooms thoroughly with heat. If it is your first time eating this species, it is best to start with a small amount to check for allergies, even if cooked.
Mushrooms grow spores as they develop. This is a natural means of reproduction. This is when people with allergies or compromised immune systems may want to consider putting fruiting mushroom kits outdoors or in a well-ventilated area. Spores in mushrooms sometimes cause respiratory irritation. In rare cases, spores may also cause irritation for some non-allergic or non-immunocompromised mushroom growers. If you are one of them, it is recommended to reduce the overall spore load by harvesting mushrooms while they are still in their younger growth stages.
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- Reviews
- Questions
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Tasty science
Awesome Block with multiple flushes.
North Spore
Thanks, Benjamin! We couldn’t do it without customers like you.

Excellent experience as a newbie
North Spore made my journey into mushroom growing incredibly simple. The instructions are great and easy to follow, the packaging and quality of the mycelium is on point, and I now feel like a mushroom goddess as my reishi and shitake are blooming out in all their fungi glory.
North Spore
We're so happy you're enjoying the experience, Meagan! Please reach out if you ever need anything.

Great stuff
It's a very good strain I love to grow them and they make it so easy and convenient to purchase them
North Spore
We're so glad you're enjoying the shiitakes! Our team is here if you need anything!

Shiitake fruiting block
The block is growing shiitake very well. I have harvested several mushrooms so far and should have a few more this weekend. They taste excellent too. I am hoping for a second fruiting later on. A fun project. I had a problem with the first order when i discovered an open seam in the packaging when I received it and you immediately sent me another fruiting block. The first block actually produced several mushrooms and is now barren and very dark color. I am hoping it will produce again. I appreciate your excellent customer service.
North Spore
Thanks for sharing, Robert! We appreciate you taking the time to share your experience.

Shitaki blocks are the easiest and best on the market!
I waited until the skin on the mycelium was brown, open it up in a fruiting box, and so many mushrooms!!
North Spore
Thanks for sharing, Siobhan! We’re so happy you’re enjoying the experience.

Shiitake grow
We received a 4 pound harvest from the first flush on the 3 grow blocks. The second flush was much lighter, but overall a fantastic grow.
North Spore
Thanks for sharing, Chris! If you need help with anything, please reach out.

Shiitake mushrooms
This was my first attempt at growing mushrooms. I received the three shiitake fruiting blocks on the buy two, get one free sale. I also received my subscription order on the same day with golden oyster, pink oyster and king trumpet blocks. Once I placed the blocks in fruiting chambers, I regularly contacted customer support. They were great! I lost the first flush of golden oysters due to environmental conditions. With the help of customer support, I had my first harvest of shiitake mushrooms. I got 2.25 lbs from the three blocks. This has been an amazing experience, and now I feel more confident in growing mushrooms. I look forward to seeing if I can get a second flush from the shiitake blocks, and for my next subscription order to arrive. North Spore is awesome!
North Spore
Your review made our day, Susan! The team is here to help if you ever need anything.

Definitely intermediate
Yielded one great flush of shiitakes, but then molded over and I removed it from my tent before attempting a second yield. I did not heed the instructions, so it's definitely my fault

Shittake
So far it’s going really well, I had a little mold spot but I’m a beginner and I think it’s totally my fault sprayed a little 70% alcohol to get rid of it. Love the lionsmane grow kit. Can’t wait to buy more with my birthday money! Definitely recommend

Great kit
Great grow block, fast growing took no time at all and started getting fresh shiitake mushrooms. Will be ordering again!