How to grow mushrooms indoors during the summer

Gourmet mushrooms often prefer a temperature of 20 Celsius (68 Fahrenheit) or below to grow indoors. Without enough air conditioning, this can be a significant challenge.

We learned this the hard way more than once, thanks to a power outage and a delayed air conditioning unit. Luckily with JCB Gourmet Mushrooms Grow Kits, you can grow mushrooms indoors without worrying about the heat created by hundreds of mushroom blocks sitting side by side in a closed room.

Here are a few ways you can grow mushrooms indoors if you're struggling to maintain a temperature below 20 Celsius (68 F).

1. Choose a grow kit that handles warmer temperatures

Some of the mushrooms we grow are less picky than others and can handle slightly warmer temperatures. Italian Oyster, Snow Oyster and Chestnut mushrooms usually tolerate temperatures up to 25 Celsius (77 F) if there is frequent misting and airflow. Blue Oyster mushrooms can handle a few degrees above 20 Celsius (68 F), but the caps grow white like the Snow Oysters. Shiitake mushrooms can also tolerate a room around 22 Celsius (72 F).

Reishi and Yellow Oyster mushrooms actually prefer warmer temperatures. We recommend the temperature for Reishi Grow Kits be between 21 and 27 Celsius (70 and 80 F). Yellow Oyster grow kits can be in a room between 18 and 26 Celsius (64 and 79 F).

Pink and Yellow Oyster mushrooms like to grow in tropical climates outdoors, but they do need consistent humidity to replicate that environment. If you can mist around five times a day to consistently maintain high humidity, you are much more likely to replicate the tropical conditions.

2. Place the grow kit in a room without much direct light

The basement is the best option to grow mushrooms if your home is feeling the heat. The ground insulates basements and shields them from the outdoor air. Basements can also be damper as warm air meets the cool walls. As long as you keep your grow kit away from a dehumidifier if you're trying to reduce the dampness of the basement, you can take advantage of that humidity with your misting.

There are other options for those without a basement. Try a closet or a room with a smaller window. You can also close the curtains to keep out the direct sunlight. Grow kits will overheat in direct light, partly because of the plastic bags.

3. Mist often

You might have noticed humidity being mentioned in the other steps as well. That's because it is very important to mist the inside of the humidity tent that goes over the growing block.

More than half of the block is water, and warmer temperatures will cause the water to evaporate. Misting the humidity tent will help the block reabsorb water. Misting cold water also helps lower the temperature of the growing block.

Misting at least three to five times a day is great – if you're at home all day, don't hesitate to check your grow kit for droplets on the humidity tent. If the water dried off, mist again to be safe. The misting is easy enough for kids to maintain the humidity of the grow kit as well.

What has been your experience growing mushrooms indoors during the summer? Let us know in the comments!


  • Hi Ann, apologies for the late response, we mainly monitor our email, social media, and the “Chat with us” function on our website.

    Thank you for your questions! For Italian Oyster mushrooms, you can stand up the bag and cut two X’s on both large sides and fold down the top of the bag. Or, you can lay the block so one of the large sides is facing up and grow each side one at a time, and you fold the top of the bag over the other side and tape it down.

    We ask that you please keep the mushroom kit away from any heat lamps or direct LED lights. If you have the LED lights directly over your plants and the mushroom kit is beside the setup (getting some indirect LED light), that should be fine. The two hours should work well.

    When you are misting the humidity tent, lift up the tent from the kit and spray the inside of the tent. You should do about 20 sprays of mist each time. You can fill up the bottle and have some left over for the next time. This is to create a humid environment for the mushrooms; it replicates our grow room where the humidity level is around 90 percent.

    I hope that helped!
    - Jonathan, one of John’s staff

    JCB Gourmet Mushrooms
  • Hello John. We bought your Italian oyster mushroom kit this morning in the Ray Friel Farmers Mkt. Following your marked X, I sliced the growing bag carefully. 1. Now, do I slice it on both sides allowing the top of the bag to fold down partially for daily misting? I clamped the moisture tent but not taping it for easier misting routines. I have growing Led lights where my other plants are and some sunlight do come halfway through the bay window, covered partially by horizontal mini blinds. I put the mushroom kit behind other higher planters. We have air conditioning set at 20 C. auto. 2. Do these mushrooms need these Led grow lights (artificial)? Usually I put these on for 2 hours & sometimes none at all. 3. With your small spray bottle, how much distilled water do I need for each misting (half a bottle or a full bottle)? My house’s humidity is about 45 and we have a dehumidifier on to keep it around this level. Looking fwd to your feedback. Thanks.


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