Mushroom Growing Temperature: Too Hot or Too Cold?

• 🌡️ Most mushroom species need temperatures of 70–86°F for colonization and 55–75°F for fruiting.
• 🧫 Heat above 86°F during colonization can make harmful bacteria grow and stop mycelium from developing.
• 🌬️ Growing mushrooms indoors lets you control temperature exactly. But it needs the right tools and to be checked often.
• 🌱 Growing mushrooms outside needs to match the seasons and natural temperature changes.
• 📊 Smart environmental sensors can cut down on growing mistakes caused by temperature by up to 40%.

Temperature is one of the most important things in growing mushrooms well. Whether you are growing mushrooms for business or just at home, keeping the temperature right at every growth stage helps you get good yields, healthy mushrooms, and fewer problems with germs. This guide will show how temperature affects types of mushrooms like oyster, lion’s mane, and shiitake. We will give practical tips to heat or cool your space. And then, we will talk about tools and ways to keep conditions just right, whether you grow inside or outside. Paired with good temperature control, our grow bags give you a practical way to achieve healthy harvests without a complicated setup.

How Temperature Affects Mushroom Growth

Temperature controls how fast and well mushrooms grow. These fungi aren't plants—they don't need sunlight. But they grow best with the right humidity, fresh air, and especially, temperature. Unlike many green-growing organisms, mushrooms react fast and sometimes strongly to temperature changes.

Each phase of mushroom development—spore germination, mycelial colonization, primordia formation, and fruiting—has different temperature needs. Temperatures outside these best ranges can lead to stopped growth, no mushrooms, or infection from bad germs.

In general:

• Colonization phase: Best temperatures are around 70°F to 86°F (21°C–30°C) depending on species.
• Fruiting phase: Often needs to be cooler. Most types do well at 55°F–75°F (13°C–24°C).

Even within these ranges, each mushroom species may have a smaller best range. This makes temperature control one of the most important parts of any good mushroom farm temperature plan.

Growth Stages and Their Temperature Needs

To grow mushrooms well every time, you need to know about the main growth stages and their temperature needs. Here's how each phase relates to temperature control:

1. Spawning / Colonization Phase

During colonization, mushroom spawn (usually in grain or sawdust) grows white, thread-like mycelium that spreads across the growing material. This fast growing stage does well with warmth and steady conditions:

• Ideal temperature: 75°F to 80°F for most species.
• Range tolerance: Some types can grow down to 70°F or up to 86°F. But they get stressed if it's hotter or colder than that.
• Importance of stability: Temperatures that go up and down during colonization can lead to uneven mycelium growth and a higher chance of contamination.

2. Fruiting Phase

Once the growing material is fully colonized, you need to make it start fruiting. This usually means making it cooler and giving it more humidity and light.

• How it starts: For many species, a temperature drop tells them the time is right to make mushrooms. This is like how seasons change outside.
• Best temperature: 55°F to 65°F depending on species. Oyster mushrooms, for example, fruit well at 60–65°F.

Below is a quick reference chart for popular types:

What Goes Wrong When Colonization Temps Are Off

During colonization, mycelium growth strongly depends on heat. Temperatures that are too hot or too cold not only slow development but may lead to contamination and other problems.

Problems When It's Too Cold

• Slowed growth: Mycelium slows near 65°F and might stop completely at lower temperatures.
• Longer colonization periods: Longer times mean a higher chance of mold or bacteria growing.
• Delayed transition: Slower colonization can delay when you start the fruiting phase. This can mess up your harvest timing.

Problems When It's Too Hot

• Heat stress: Mycelium grows well in warm conditions—but not hot ones. Temperatures above 86°F can lead to heat damage, killing parts of the mycelium.
• Bacterial bloom: Too much warmth can make bacteria grow. This might lead to sour smells or slimy spots (Cutler, 2020).
• Increased contamination risk: Warmer, moist growing materials are perfect places for molds to grow. These molds can fight with or destroy your crop.

Fruiting Problems Caused by Bad Temperature

The fruiting phase is very sensitive to changes in the environment. While you might not notice problems during colonization until it’s too late, fruiting issues are easier to see and touch.

Too Cold

• Pins appear late: If the temperature drops too low, your mushrooms might not make pins at all. Pins are early mushrooms.
• Poor growth rate: Even if some fruit appears, they might grow slowly and not very well.
• Deformation: Some cold-affected mushrooms might get twisted stems or badly shaped caps.

Too Hot

• Abortion: Early mushroom pins may start growing but stop growing halfway, turn dark, and die.
• Shriveled fruits: High heat can make caps dry out or split during growth.
• Reduced yields: Too much warmth when fruiting will make mushrooms small and cut down on how many you get (Miller, 2021).

Being steady is very important: if the temperature often goes from hot to cool—even inside the best ranges—it can make the growing area unstable. This can stop mushrooms from fruiting at all.

Managing Mushroom Growing Temperature Indoors

Indoor mushroom growing lets growers control the environment really well. But getting the best mushroom growing temperatures indoors needs careful work, planning, and sometimes, money for tools.

During Colonization

• Heated incubation boxes or grow cabinets: Special boxes with insulation help keep them warm.
• Heat mats or germination pads: Give a small, controlled amount of heat right under the substrate box.
• Aquarium heaters in water baths: These are good for keeping a steady colonization temperature in jars.
• Use ambient room heat: Put colonization bins in closets, utility rooms, or warm basements with steady temperatures.

During Fruiting

• Space heaters with thermostats: They work well to keep small grow tents or homemade chambers at 55–65°F.
• Portable air conditioning: They help cool rooms that are too warm, especially when growing in summer.
• Oscillating fans and inline duct fans: They help move air and also control humidity and temperature.
• Grow tents with insulated walls: They keep heat and humidity in check better than open areas.

Tips for Monitoring

• Check both the air temperature around them and substrate temperature.
• The growing material can make its own heat as the mycelium grows. So, the temperature inside it is often higher than the room's temperature.

Tips for Outdoor Mushroom Growing

Although you give up some control outside, nature can still give you great growing conditions if you time it right.

Key Strategies:

• Pick the right season: Pick a mushroom type that grows well in spring or fall, if you live where seasons change a lot.
• Shaded environments: Keep grow beds or logs under trees or awnings to stop them from getting too hot.
• Mulch and straw coverings: These damp insulating layers control the ground temperature and hold moisture.
• Trench growing methods: Using dug-in beds lets you use the earth's steady temperature.
• Monitor microclimates: Even a few feet of distance (e.g., north vs. south-facing fence) can change how well they grow.

Shiitake and lion's mane are good choices for growing outside if you live where the seasons vary a lot.

How to Warm Things Up

Indoor growers often deal with cold, especially in basement setups or during colder months. Here’s how to slowly make mushroom farm temperatures warmer:

• Heat mats or under-tank pads: These are good for warming growing trays and small colonization bins.
• Low-watt space heaters: They give warmth where you need it. Pick ones that turn off by themselves.
• Heating cables: Good for wrapping around jars or logs in a fruiting room.
• Insulated growing areas: Use reflectix, foam board, or blankets to keep heat in.
• DIY insulated boxes: Put heat lamps or reptile bulbs in closed boxes with temperature controls.

Always measure temperatures often to stop it from getting too hot and drying out the growing material.

How to Cool Your Grow Space

Mushrooms get too hot more often than they get too cold, especially in warmer conditions or summer months. To cool well:

• Increase air circulation: Use standing fans or filtered intake/exhaust systems.
• Install portable A/C units: They work especially well in closed growing areas like tents or rooms.
• Use ultrasonic humidifiers: They give off a light mist. This also cools the air as the water dries up.
• Ice packs and frozen bottles: A fast, cheap way to save mushrooms from hot spells.
• Opening room doors/windows: Make air move across the room or bring in cooler night air.

For fruiting rooms, keeping temps under 75°F is often the key limit for many mushroom types.

Monitoring: Sensors Are Your Best Friend

Smart sensors have changed mushroom farming a lot. They give you environmental data almost instantly. This means fewer failures go unnoticed.

Recommended tools include:

• Digital probe thermometers: Attach these right to the growing material or container to get correct readings.
• Smart sensors with wireless alerts: They spot quick changes in high or low temperature right away.
• Temperature and humidity data loggers: They keep records of long-term patterns. This is helpful for figuring out why crops failed or where things could work better.
• Sensor placement tips:
  • Place one near the base of your grow containers (substrate level).
  • Mount another for air temperature readings.

According to Ramirez & Liu (2022), using digital sensors cuts down on human monitoring mistakes by 40%—this is a big help for getting steady harvests.

Common Temperature Mistakes to Avoid

Avoid these common mistakes new growers make when managing mushroom farm temperature:

• Placing heat sources too close to substrate: This can dry out or “cook” your grow bags.
• Ignoring ventilation: Heat makes mushrooms grow faster, but it also raises CO2. Without air moving, this stops growth.
• Thinking your home's air temperature is the same as the growing area: But in fact, the growing material can be a few degrees different.
• Not checking your tools: Make sure your thermometers and sensors are set correctly for exact readings.

Correcting these issues often results in better growth and more output right away.

DIY Solutions for Budget Growers

If you're growing mushrooms indoors on a budget, don't worry. Cheap options can still give you a lot of mushrooms:

• Use insulating blankets or bubble wrap around colonization jars to keep heat in.
• Build mini fruiting tents from clear plastic tubs and spray water several times a day.
• Choose rooms with steady temps like bathrooms, closets, or under-stair areas.
• Use sunlight for heat: Start colonization near windows warmed by the sun. Just keep them out of direct sunlight.
• Use rice cookers or coolers (unplugged) as incubator boxes—simple, clean, and they work.

Careful attention to detail with these homemade methods can produce as much as more expensive setups.

Temperature Tips by Mushroom Type

Aside from growth phases, different mushroom species need different temperatures all the way through:

• Oyster Mushrooms (Pleurotus):
  • They grow very fast when colonizing at 75–80°F.
  • They fruit in cooler spots (60–65°F); they need high humidity.
• Lion’s Mane (Hericium erinaceus):
  • Likes cooler conditions even when colonizing (70–75°F).
  • They fruit steadily around 60°F and form dense, shaped mushrooms.
• Shiitake (Lentinula edodes):
  • Colonization is steady at 70–78°F.
  • They need a shock phase. This sometimes means soaking them in cold water. Then they fruit at 55–65°F.

Final Tips for Matching Temperature to Your Grow Setup

Temperature isn’t just a background detail—it is the most important part of growing mushrooms well whether indoors or out. Here’s how to match your plan to your growing setup:

• Indoor growers get exact control. But they need to watch things closely and buy sensors.
• Outdoor growers must time their grows carefully and depend on types that can handle natural temperature changes.
• Don’t forget humidity: It works with temperature for both colonization and fruiting.
• Check both air and substrate temperatures for best results and the lowest risk of contamination.
• Use tools, not guesses—thermometers, sensors, and thermostats make success clearer.

With steady temperature control, even beginners can get good results from every harvest. And if you’re ready to put that theory into practice, Zombie Mushrooms offers beginner kits with growing materials and bags that work with different temperatures. This makes growing easy inside or out.

For more tips and examples of success, visit our growing blog—where science and fungi come together.

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Citations

Arora, P. (2021). Ideal Temperature Ranges for Mushroom Cultivation.
Cutler, D. (2020). Managing Environmental Stressors in Mycology.
Miller, S. (2021). Top 5 Reasons Amateur Mushroom Grows Fail.
Ramirez, L., & Liu, T. (2022). Improving Indoor Agriculture with Smart Sensors.

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