Shiitake Mushroom Grow Kit Instructions

Congratulations on your new grow kit, we hope you enjoy growing mushrooms as much as we do! Scroll down to learn how to care for your new treasure. 

If you have any questions or concerns please feel free to reach out to us via email at

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Prepare the Grow Kit

Items Needed to Start


Razor Utility Knife/Scissors

To make a cut through on side of the plastic bag.


Have a fruiting location in mind for your kit already?  Please follow our essential tips & tricks to ensure your block will be happy, healthy, & fruitful. Don't wing this part!

Items Needed for Ongoing Care



Hand sprayer to keep up the environment's humidity.

Non-chlorinated Water

Distilled or well water preferred. 

Good Passive Air Flow or Fan

Mushrooms Inhale Oxygen and Exhale Carbon Dioxide. Fresh air is important!

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1 - Shock Your Shiitake & Let It Breathe

Shiitake's are hearty little mushrooms that benefit from a physical shock. This can be achieved by picking up your block and dropping it from roughly a foot off the ground. This helps to induce fruiting!

Next, you want to let the block breeeeathe by giving it some fresh air. To achieve this, just stand the block upright and make a slice across one side of the biodegradable plastic bag, about an inch above the block. This simulates their growing through the block to the edges and lets them know it's time to start preparing to fruit.


2 - Let it Chill

The next step in inducing a robust fruiting shiitake is to expose them to a 10 degree or greater temperature drop. While not necessary, this will help you get a stronger initial fruiting. 

Our shiitake best colonize at 70-75 degrees so putting the block in a place that is 65 or below for 12-24 hours before placing in a slightly warmer area will do the trick. You can even put the in the refrigerator overnight!

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3 - Wait For Primordia 

Time to start thinking about moving your kit to a humid location. This could either be a shady spot outside or an indoor humidity chamber. If keeping your block outdoors store it in a place where it will be protected from direct sunlight and insects. An indoor humidity chamber can be as simple as a plastic storage tote or an aquarium that you mist with a spray bottle periodically or just a humid room. In the warmer months your kitchen or basement might work great!

Over the next few days, small brown lumps will start to form around your block, inside of the bag. Once these reach nickel size, it is time to remove the bag entirely with a sharp knife or razor. Continue reading for more on storage and preferred conditions. 

4 - Find a Nice Home

Location, Location, Location! Place your kit somewhere humid. As mentioned above basements, kitchens and even bedrooms are a good indoor options. And in warmer months shady outdoor areas also work well for shiitake, particularly if you can protect them from insects in shaded greenhouse, garage, shed, or screen porch.

For most indoor climates, you will need a fruiting chamber. This can be a room with a humidifier, a storage tote, aquarium, or a large clear plastic bag. In warmer months any room without air conditioning will do. And practically any container that will comfortably hold the bag, allow in a decent amount of light, and decent airflow will work. The amount of light to comfortably read a book is about the right amount.

Shiitake mushrooms produce a fair amount of Carbon Dioxide (CO2). High CO2 levels in the fruiting environment will cause elongated stems to form. Additionally, higher CO2 levels favor mold growth.

You will want to make sure you have some airflow at all times if possible. If a transparent container which cannot breath is used, such as a clear plastic container, consider putting it on its side with a loosely fitting plastic or cloth cover over the opening. Ensure this opening is not blocked and open your chamber a couple times a day to force in fresh air with hand-fanning, or using small fan. 
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Ongoing Care

Now all you need is to provide additional fresh air and humidity 2-4 times per day. Simply open your chamber and mist the walls and air with non-chlorinated water, well water and distilled water work best.

You should avoid misting the mushrooms directly. But you do want your chamber to have some visible mist or condensation in it at all times. You will need to balance airflow and humidity. But you should not directly mist mushrooms, as it invites mold and bacterial growth, as well as bruising.

Whenever you open your chamber to mist, you should also fan out the chamber. You can use a fan, air purifier, a magazine or your hands. Although getting air exchange is important and hand-fanning is not terribly effective. A small fan or purifier is preferred.

Watch Them Grow!

Over the next week or so your mushrooms will rapidly expand. Once the caps have unfurled to the point that the cap margin is visible and the gills are exposed, it is time to harvest! Simply cut your mushrooms off near the base of the stem with a sharp pair of scissors.

Once you have harvested all the mushrooms, simply continue to tend to the kit the same way and after a week or two, a new set of mushrooms will appear. This can happen 3-5 times.

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  • If you see long stems forming on your mushrooms this is likely caused by inadequate airflow or excessive CO2 in the fruiting environment. Increase fresh air flow.

  • At harvest, just twist or cut your mushroom off the kit. Continue as usual and roughly in a week to two weeks later new mushrooms will begin to pin. This may happen up to 5+ times. Each flushing will produce fewer mushrooms.

  • If mold or mildew forms on the block, we suggest moving it outside and spraying the block down with a hose. Then finding a nice shady outdoor spot for it. Mushrooms tend to be healthier and more resistant to mold when outdoors in abundant fresh air and indirect sunlight.