Guide · with a kit

Grow mushrooms at home

A grow kit is a ready block that the mushroom threads (mycelium) have already colonised. Your job is to give it the right spot, humidity and air. Oyster mushrooms are the easiest place to start.

Jump to the steps Grow kits

A cluster of oyster mushrooms growing from a block

Step by step

1

When the kit arrives

If you are not starting straight away, the kit can wait in the fridge for up to two weeks. Do not open the box or take the bag out; it stays inside the box. [1]
2

Pick a spot

Somewhere with indirect light and fresh air; the kitchen counter is ideal. Avoid direct sun and radiators. Fluorescent or LED light is enough. [1][2]
3

Make the cut

Through the window in the box, make a cut about 2.5 cm (1 in) wide in the bag with a clean knife. Stand the kit on a shallow dish. [1]
4

Keep it humid

Mist the cut area once a day with clean water. Drape the humidity tent (a clear bag) loosely over the kit and snip about 5 cm (2 in) off its corners for airflow. Mushrooms like it humid: sources suggest 80–90% relative humidity while fruiting. [1][3][4]
5

First pins

When a white clump of mycelium starts pushing out of the cut, baby mushrooms are on the way. Take the tent off (keep it for the next round) and mist twice a day, more if they look dry. Without enough humidity they stop growing. [1]
6

Harvest

Pick when the cap edges start to curl outwards or upwards: twist the cluster off the kit. Do not let them over-mature on the kit; they release masses of spores, which can bother some people. [1][2]
7

Rest and go again

After harvesting, rest the kit somewhere dim for 2–3 weeks. Put it in the fridge the night before restarting, then set it on the dish, mist and cover it again. A kit can fruit 3–4 times; when it is spent, add it to the garden or compost. [1][2]

If your kit's own instructions differ from these general steps, follow them. Fresh mushrooms keep for about a week in a paper bag in the fridge. [1]

Troubleshooting

If something goes wrong

Mushrooms shrivel, edges dry: Not humid enough. Mist more often and drape the tent back on loosely. [1]
Long thin stems, tiny caps: Too little fresh air. Carbon dioxide building up in a closed space disrupts growth; leave the tent open and air the room. [3]
Pins forming inside the bag, away from the cut: Remove the cover completely. [2]
A patch of green mould: Airborne mould can get in once the bag is cut. Scrape a small patch away with a clean spoon; if it spreads or the kit smells bad, do not eat from that kit and throw it out. [1]
Nothing for weeks: Give the kit a night in the fridge, then mist it and cover it again the next day. Fresh air helps trigger fruiting. [1][3]