Shitake Mushroom Culture Problems
Answered by: Inge Poot
Question from: Elaine Freedman
Posted on: August 4, 1998

My shiitake mushroom kit is growing moulds – green, white, black. It is by a basement window.

I’ve been cutting off the mouldy bits. What should I do?

A mushroom is simply the fruiting body of a mould. You could think of it as the "flower" of a mould. The white mould is the "mycelium" of a fungus and it is equivalent to the green part of a flowering plant. Since the majority of fungi have a white mycelium you have to watch it carefully to make sure the mycelium you allow to grow is not some other fungus. When it turns green or black, you know it is not the shiitake mushroom since shiitake only sometimes turns dark brown during the maturation process. During maturation the block must be kept at 55-75 degrees Fahrenheit (13-24 degrees Celsius) and must receive some light. The mycelium also produces carbon dioxide and you have to ensure that it does not dissipate too quickly.

You did the right thing by cutting off the contaminating fungi. Try to give your block optimal conditions for the growth of shiitake and then the other fungi will have less of a chance.

Do check that the block is not too dry. If it seems quite dry to the touch, because it dried out in transit, soak it for four to eight hours in very cold water (35 to 50 degrees Fahrenheit or 2 to 10 degrees Celsius). Warm water will kill the mushroom mycelium.

You may have to thump the block of medium onto a table three or four times to encourage it to start the fruiting process!

When introducing water mist into a dry growing environment, avoid wetting the block directly, but try instead to hit the sides of your enclosure with the spray.

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