Can Mushroom Grow Kits Survive Hot Weather? Summer Growing Tips

Summer can be a challenging time to grow mushrooms. When the temperature of the growing environment is too hot, mushroom growth can dry out and stall, and in some cases, pinning may not occur at all. However, it's not all doom and gloom. Some species are more tolerant of the heat, and for some, it can even be beneficial. For the other types of mushrooms which struggle with warmer temperatures, there are several things you can do to help your mushroom kits when the going gets a little too hot. Keep reading for our top tips on what to do to ensure success with your mushroom kits in the summer.

Best Mushroom Kits For Warm Temperatures

If you plan to grow mushrooms during hot weather or your home runs warm, the best thing you can do to ensure success is choosing a variety that grows happily at higher temperatures.

Phoenix Oyster (Pleurotus pulmonarius)

This UK-native species also goes by the common name Summer Oyster because it is found in the wild at all times of year, including throughout summer, making it the perfect candidate for growing during the hottest time of year. This is a mushroom that you can either grow indoors with a ready-to-grow kit or outdoors in a mushroom bed or in logs.

Tarragon Oyster (Pleurotus euosmus) Another UK-native species of oyster, this oyster mushroom is so-named because it smells similar to fresh tarragon! It is a rare find in the wild and has only been observed growing in the British Isles. Like its cousin, the phoenix oyster, it can also be found fruiting in the summer months in the wild and can also be grown outdoors.

Pink Oyster (Pleurotus djamor)

As a tropical species, pink oyster thrives in warm conditions and is one of the best mushrooms to grow during the summer months. It actually prefers higher temperatures than most cultivated mushrooms, typically fruiting fastest when temperatures are around 20-30°C.

In warm weather, pink oyster mushrooms will often grow rapidly, producing bold clusters of vibrant pink mushrooms in just a matter of days. For summer growers, this makes it an excellent choice, especially in homes that would otherwise be too warm for other species.

Lion's Mane (Hericium erinaceus)

Not all lion's mane can fruit well when it's warm, with most preferring temperatures of around 14-20°C. At Fat Fox Mushrooms, we have specially selected strains that are heat-tolerant - all the way up to 30°C! We've tested them plenty of times and it grows without bother even at the very top of the threshold.

Red Reishi (Ganoderma lucidum), Antler Reishi (Ganoderma multipileum), and Black Reishi (Ganoderma sinense)

All three of the reishi species that we offer are not only heat-tolerant but will benefit from warmer temperatures, which give the usually slow-growing fungi a boost. If you're already growing reishi at home, you'll see a noticeable growth spurt in summer.

How to keep mushroom kits cool in hot weather

If you have mushroom grow kits that are more sensitive to the heat, it's important to mitigate heat stress for the best results. It's still possible to fruit heat-sensitive species so long as you take care to create an appropriate environment and some clever tips to keep the mycelium cool.

1. Move mushroom kits to the coolest room and place on tiled surfaces if possible

During hot weather, move your mushroom kit to the coolest part of your home. A north-facing room that receives little direct sunlight is often the best choice, as it stays at a more stable temperature throughout the day. If possible, place the kit on a tiled or stone floor rather than carpet or wood, as these surfaces tend to stay naturally cooler and can help reduce heat build-up around the kit. Avoid any locations with lots of appliances or anywhere that gets direct sunlight and can heat up quickly. Although the kitchen is often an ideal place to grow mushrooms because of its humidity, it can become surprisingly warm during a heatwave, especially if you're using the oven or hob. If you're cooking regularly, it's usually better to move the kit to a cooler room until temperatures return to normal.

If you have a small thermometer like this, place it next to your kit to monitor the temperature throughout the day. This will help you spot unexpected heat spikes and decide whether you need to move the kit to a cooler location or take additional steps to keep it within its ideal fruiting range.

2. Don't leave mushroom kits directly in front of air conditioning units or fans

Although a cool room is one of the best places for a mushroom kit during hot weather, avoid placing it directly in front of an air conditioning unit or in the path of flowing air.

Whilst air conditioning lowers the temperature, it also removes moisture from the air. A constant stream of cold, dry air can quickly dry out developing mushrooms, causing cracked caps, split stems or stalled growth. For the same reason, you should also avoid placing mushroom kits directly in front of fans.

Instead, position your kit elsewhere in the room where it will still benefit from the lower temperature without being exposed to direct airflow. This keeps the growing environment cool while allowing humidity to remain high around the mushrooms. For more of a cooling effect, you can place a frozen bottle of water in front of the fan. The airflow will pass over the cold bottle and distribute it across the rest of the room.

3. Keep kits in the fridge temporarily

Most cultivated mushroom species can be safely stored in the fridge without harm. The exceptions are tropical species such as pink oyster and blood reishi which cannot withstand very cold temperatures.

If you haven't yet started your mushroom kit, you can store it in the fridge for up to 4 weeks if need be to delay starting it until after a heatwave has passed. With kits that are already pinning, if temperatures are close to or exceeding 30°C, you can move the kit to the fridge temporarily for a few days to mitigate heat stress.

In the case of velvet shank (Flammulina spp.), you can keep it in the fridge the entire time the mushrooms are growing. Adapted to fruit in the depths of winter, it can continue growing quite happily at typical refrigerator temperatures.

Important: do not freeze any mushroom kits, as this will kill the mycelium!

4. Use a damp tea towel to create evaporative cooling

Just like us, your mushrooms will appreciate the cooling effect of a simple damp tea towel. As the water in the towel evaporates, it provides a small amount of evaporative cooling, which can lower the temperature around the block by a couple of degrees. It's not a dramatic effect, but during a hot spell, it may be enough to keep the kit within a better fruiting range.

A few tips:

• Only wrap it around the substrate bag (taken out of the cardboard box it came housed in), not the mushroom clusters or the fruiting hole that you've cut in the bag. The mushrooms still need fresh air and shouldn't be kept pressed against wet fabric.

• Keep the towel damp, not dripping. A soaking wet towel can leave the kit sitting in water and create unnecessarily wet conditions.

• Ensure there is some airflow. Evaporative cooling works best when air can circulate. A gentle breeze in the room is fine, but don't point a fan directly at the mushrooms as they'll dry out.

• Refresh the towel as it dries. Once it's dry, it no longer provides any cooling.

5. Increase misting during hot weather

Your mushroom kit will dry out much faster during a heatwave. The substrate loses water more quickly and developing mushrooms can dry out before they have a chance to grow properly. If the surface of the substrate becomes too dry, pinning may slow down or stop altogether.

Keep a close eye on your kit and don't be afraid to mist a little more frequently than usual.

As a general rule, it's better to mist lightly and more often during hot weather than to drench the kit all at once.

Final thoughts

Hot weather doesn't have to mean the end of your mushroom-growing season. By choosing heat-tolerant species where possible and taking a few simple steps to keep your mushroom kits cool, you can continue harvesting fresh mushrooms throughout the summer.

If temperatures climb above your kit's preferred range, don't panic. Moving it to a cooler room, using evaporative cooling with a damp tea towel, or even temporarily storing it in the fridge can help protect the mycelium until conditions improve. In most cases, a short heatwave will simply slow growth rather than ruin the kit altogether.

If you're planning ahead for summer growing, consider choosing naturally heat-loving species such as phoenix oyster, tarragon oyster, pink oyster, or one of our heat-tolerant lion's mane strains. These are much better suited to warm homes and are far more likely to produce reliable harvests during the hottest months of the year.

Frequently asked questions

What temperature is too hot for mushroom kits?

Most mushroom grow kits perform best between 14–24°C, depending on the species. When temperatures consistently exceed 28–30°C, growth can slow significantly, and the substrate may dry out more quickly. Some heat-tolerant species and different strains can cope better (such as pink oyster, reishi and our heat-tolerant strain of lion's mane), so it's important to check the growing requirements of any kits you buy.

Can mushroom kits survive a heatwave?

Yes. In most cases, short periods of high temperatures will not permanently damage a mushroom kit. Growth may slow or pause during the hottest days, but the kit will usually recover once temperatures return to a suitable range.

Should I mist mushroom kits more in summer?

Yes. Warm air increases evaporation, so mushroom kits often need more frequent misting during hot weather. The goal is to maintain humidity without soaking the substrate.

Can I use a fridge to cool a mushroom kit?

Yes, most mushroom kits can be temporarily stored in the fridge during extreme heat or before starting fruiting. However, tropical species such as pink oyster should not be refrigerated. Always avoid freezing kits, as this will kill the mycelium.