Where to place your mushroom kit at home for the best results.

Place your mushroom kit indoors, in a room between 14 and 21 degrees, out of direct sunlight, and away from radiators or other heat sources. Most kitchens, utility rooms, bathrooms, and spare bedrooms work well.

That is the quick version. In practice, each variety has a slightly different ideal temperature, and UK homes have quirks (radiators, draughty windows, warm loft rooms) that can make the difference between a big harvest and a disappointing one. This guide covers the best spots in a typical UK home, the temperatures each variety prefers, and how to manage the seasonal challenges that come with growing mushrooms indoors.

A kitchen worktop away from the hob and window is one of the most popular spots for a mushroom kit.

The three things your kit needs from its location

Mushroom kits are not fussy, but they do have three basic requirements from wherever you put them.

Stable temperature. All of our indoor kits grow between 14 and 21 degrees, with most varieties having an optimum around 17 to 18 degrees. Mushrooms respond to temperature changes, so a steady temperature means more than hitting the exact ideal number. Fluctuations (warm during the day, cold at night) can stall growth or cause pins to abort.

Indirect light. Mushrooms need some light to develop properly shaped and coloured caps, but not direct sunlight. A room with a window is fine as long as the kit is not sitting on the windowsill in the sun. Daylight from across the room, or even artificial room lighting, is enough. Complete darkness is not ideal either, as it can cause elongated stems and small caps.

Some airflow. Mushrooms produce carbon dioxide as they grow. Without fresh air, CO2 builds up around the kit, which leads to long, leggy stems with tiny caps. You do not need a fan. Just make sure the kit is not sealed in a cupboard, wardrobe, or enclosed space. A normal room with a door that opens occasionally is plenty.

Best rooms in a UK home for growing mushrooms

Kitchen. The most popular choice. Kitchens tend to have good light, reasonable airflow, and you will remember to mist your kit because you see it every day. Place it on a worktop or shelf away from the hob, oven, and any sunny windows. Avoid putting it directly next to the kettle or toaster where steam and heat spikes are common.

Utility room. Often the ideal spot. Utility rooms tend to be cooler and more stable in temperature than kitchens, with reasonable humidity from the washing machine. They are usually out of direct sunlight and away from radiators.

Bathroom. Good natural humidity makes bathrooms a strong option, especially for varieties that need higher moisture levels like Lion's Mane. The main thing to check is temperature. If your bathroom gets very warm during showers and then cools down significantly, the fluctuations could be an issue. An unheated or lightly heated bathroom is often perfect.

Spare bedroom. A room that is not heavily used and does not have the heating on constantly can work very well. The temperature tends to be stable and cooler than the main living spaces, which most mushroom varieties prefer.

Hallway or landing. Often overlooked, but hallways and landings frequently sit at a moderate, stable temperature and have indirect light from nearby rooms. Not ideal if the area is draughty, but worth considering if other rooms are too warm.

It is very important to locate your kit away from heat sources such as this.

Ideal temperature for each mushroom kit variety

All of our indoor kits grow within the 14 to 21 degree range, but each variety has its own sweet spot. Growing at the optimum temperature produces faster, healthier growth and bigger yields. Growing within the wider range still works, just more slowly.

A few varieties sit outside the standard range. Reishi can handle warmer temperatures up to 25 degrees. Enoki prefers cooler conditions, between 10 and 18 degrees. Lion's Mane is particularly heat sensitive and must be kept between 10 and 20 degrees.

If you are unsure about the temperature in a particular room, a simple room thermometer (available for a few pounds) placed next to the kit for a day or two will give you a clear picture. Check it in the morning and evening to see how much the temperature swings.

Managing temperature through UK seasons

Winter. The biggest challenge in winter is central heating. Many UK homes run radiators that push room temperatures above 21 degrees during the day, then drop to 14 or 15 degrees overnight when the heating switches off. This swing can stress mushroom growth. The fix is to place your kit in a room where the heating is either off or set low. Utility rooms, spare bedrooms with the radiator valve turned down, and unheated hallways are often ideal. Avoid placing the kit in the main living room where the heating runs all evening.

Summer. Heatwaves can push indoor temperatures above the safe range for many varieties, especially Lion's Mane (which must stay below 20 degrees) and Enoki (below 18 degrees). During hot spells, move your kit to the coolest room in the house, typically a ground floor room on the north side of the building. Bathrooms with tiled floors tend to stay cooler. You can also keep windows open at night to help reduce core temperatures. If your home regularly exceeds 25 degrees in summer, consider waiting until autumn to start a new kit, or choose Reishi which tolerates warmer conditions.

Spring and autumn. These are the easiest seasons for growing mushrooms in the UK. Indoor temperatures naturally sit in the 15 to 19 degree range without much intervention, and humidity tends to be reasonable. If you are starting your first kit, spring or autumn gives you the best chance of success.

Light: how much do mushroom kits actually need?

Mushrooms are not plants. They do not photosynthesise and do not need sunlight to grow. However, they do use light as a signal for how to develop. Without any light, mushrooms tend to grow elongated stems with undersized caps as they "search" for a light source.

The amount of light needed is minimal. Normal room lighting or indirect daylight from a nearby window is more than enough. You do not need a grow light, a lamp, or any special setup. If you can comfortably read a book in the room without turning on a light, the mushrooms have enough.

What to avoid is direct sunlight hitting the kit. This dries out the surface, raises the temperature of the growing block, and can cause rapid dehydration between misting sessions. If the kit is near a window, make sure the sun does not fall directly on it at any point during the day.

Airflow: why mushroom kits should not be sealed away

As mushrooms grow, they produce carbon dioxide. In the wild, this disperses naturally. In your home, it can build up if the kit is in an enclosed or poorly ventilated space. High CO2 levels cause mushrooms to develop long, thin stems with tiny caps as they stretch upward searching for fresh air.

The solution is simple: place your kit in an open room where air moves naturally. You do not need a fan. Opening a door or window briefly each day is usually enough. If you notice your mushrooms developing unusually long stems with small caps, it is almost certainly an airflow issue rather than a light or temperature problem.

Some varieties are more sensitive to CO2 than others. King Oyster in particular needs more fresh air than standard oyster varieties. If you are growing King Oyster, make sure the bag opening is generous and consider gently fanning the kit once or twice a day after misting.

For a full guide on balancing humidity and airflow during misting, see our misting guide.

Avoid locating your kits in an area which is too enclosed.

Placement with pets and children in the house

All of our kit varieties are food-safe, commercially grown species. The mushrooms are not toxic to children, cats, or dogs. If someone (or something) nibbles a mushroom from the kit, there is no danger. The growing substrate is also non-toxic, though it is not designed to be eaten.

The main concern is keeping the kit undisturbed. Cats are particularly good at knocking things over, scratching at interesting textures, and investigating anything new in the house. Dogs may be attracted to the earthy smell of the substrate.

Place the kit on a high shelf, a worktop, or behind a closed door if your pets are especially curious. A bathroom or utility room with the door kept shut works well for both temperature stability and pet-proofing.

For more detail on mushroom safety around pets, including what to do if a pet eats a wild mushroom found in the garden, see our guide on whether cats and dogs can eat mushrooms.

Frequently asked questions

Published by Merryhill Mushrooms / Sussex, UK