Gardening Question From Martha:

I have access to a commercial mushroom farm that makes its spent mushroom medium available at no charge to gardeners. This seems to be a terrific addition for my raised beds. I once toured a mushroom farm and saw that they sterilized the medium before onoculating it with the mushroom spawn. I’d like to hear your comments about the value of this seemingly wonderful growing medium.

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Answer From Pat:

Mushroom compost is great except that it usually has a high salt content which can damage plant roots. If you water a lot this does not matter since the salt will wash away, but if you have a drought resistant garden this might be a negative. Heavy winter rains can help wash away salts.

Photo by derekmarkham