Hi Ted,
Great question, and I’m sure one that alot of other people may have as well!
Oyster mushrooms are an incredibly versatile species that has been shown to grow on more than 100 different ‘waste’ materials, including, straw, sawdust, cardboard, cottonseed hulls, chopped corncobs and many more.They are particularly good at utilising the nutrients they need from a wide range of materials, including coffee grounds.
They are also very fast to colonise the substrate – important when dealing with ‘semi sterile’ coffee grounds, which are almost always going to harbour some competitor mould spores. These mould spores will take over the coffee if the mushroom species grown on it doesn’t colonise the grounds quickly within 7-10 days.
Oyster are probably the easiest mushrooms to grow overall, which is another reason why they have received most attention in relation to growing on coffee, where the emphasis has often been on finding a simple technique which anyone can do with limited equipment.
However, almost certainly there are other species which will grow on them to varying degrees. We have done limited trials with Shiitake, Shimeji and Maiitake with poor results and so have focussed on Oysters ever since, but there is still much to explore.
Button or chestnut mushrooms normally grow on a mix of manure and straw, and it’s possible that at least some of this mix could include coffee grounds, but really the field is open for further exploration.
Hope this helps and do let us know if you have any luck with other varieties.
Best wishes,
Adam
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