Growing Oyster Mushrooms at Home
The grow bag contains a block composed of mushroom mycelium, a mix of sawdust, straw and wheat bran (which nourish the mushrooms), grain and water. Once fully colonised, keeping the bag closed in the fridge will slow down its growth and postpone fruiting. In order to fruit, oyster mushrooms require light, humidity and fresh air. However; avoid direct sunlight and constant air streams as they will tend to dry out the mushrooms; ambient light or fluorescent lighting at a distance of at least 3 metres is enough. See the table below for ideal fruiting temperatures.
Before fruiting the block, it is important to create an appropriate environment to maintain 85% relative humidity. This step is important to ensure the development of the primordia (budding mushrooms) into mature mushrooms. A small grow tent, a plastic tote box, an aquarium, a terrarium or even a plastic bag large and rigid enough to create a dome are all viable options. This container must not be fully sealed. Mushrooms require oxygen to grow correctly and they produce a large amount of CO2, especially while fruiting. The container may be perforated and/or left partially open and should be ventilated a few times a day.
- Once ready to grow your mushrooms, make an “X”-shaped incision about halfway up the bag taking care not to damage the mycelium. Then fold down the top (empty part) and hold it in place with tape or an elastic. If primordia have already appeared on the top of the block, carefully cut off the top of the plastic bag instead of making an “X” in the side.
To provide a source of moisture, either pour water in the bottom of your fruiting container or place a bowl of water inside it. Then place the bag in the container, making sure not to submerge the opening you made in step 1. Depending on the species, the ideal temperature for primordia formation may vary. Below are the ideal fruiting temperatures for the oyster mushrooms:
Blue, white and Grey Oyster Mushrooms: 10-20°C
Phoenix Oyster: 15-28°C
Pink and Yellow Oyster: 18-30°C
Elm Oyster: 10-18°C
- Every day, lightly mist the interior surfaces of the container with water. Make sure to vent out the accumulated CO2. Keep an eye on the mushrooms’ growth. If the caps stay small and the stems elongate and twist in several directions, it is a sign the mushrooms lack oxygen. If they crack, start yellowing or stagnate, it is a sign they have dried out. Dry mushrooms stop growing. In this case, remove all dried mushrooms from their point of attachment and let the block reproduce new primordia.
- The mushrooms will be ready to harvest once the edge of the caps start to slightly unfurl. If left longer they will drop their spores and begin to degrade. Under ideal conditions, up to ½ of the block’s initial weight may be harvested over several flushes. In between harvests, the mycelium may benefit from a period of rest without humidity, in the fridge. If it seems too dry it can be submerged or rinsed with water. Drain excess water and put it back in the container. Make incisions over primordia that may have formed in other places under the bag. Soon new mushrooms will appear!
- After a few flushes, the substrate no longer contains enough nutrients. The spent block may be composted or used to inoculate a new substrate.