Growing oyster mushrooms on coffee grounds
Mix coffee grounds less than 24 hours old with 10 % oyster mushroom spawn, let it colonise warm and dark for 2 to 3 weeks and then cut holes in the bag. After 5 to 10 days pins appear, and 5 to 7 days later you harvest.
GroCycle (VK) · BS-38Brewing has already largely pasteurised fresh coffee grounds. That makes them a cheap start. According to GroCycle, old coffee grounds are the main cause of mould.
GroCycle (VK) · BS-38What do you need?
Oyster mushroom grain spawn, fresh coffee grounds, scales, a grow bag with a filter or a bucket with a lid, a knife and a plant sprayer. From 1 kg of coffee grounds also hardwood pellets or pasteurised straw.
GroCycle (VK) · BS-38Steps 1–3: preparing
Clean your work surface, hands and bag or bucket. Only use coffee grounds that are less than 24 hours old and do not leave them for days in an open container.
GroCycle (VK) · BS-38Steps 4–5: mixing and filling
Weigh the coffee grounds and mix in 10 % spawn. From 1 kg, mix in 20 % hydrated hardwood pellets or pasteurised straw. Fill the bag or bucket, press lightly and close.
GroCycle (VK) · BS-38Step 6: colonisation
Keep the mixture warm (20–24 °C) and dark for 2 to 3 weeks, until everything is colonised white. At 20 °C you are at the bottom of that range: then expect the longer side.
GroCycle (VK) · BS-38Steps 7–9: fruiting and harvest
Cut holes of 2–5 cm, place the bag somewhere with indirect light and spray daily. Pins appear after 5 to 10 days, and 5 to 7 days later you can harvest. Keep spraying: one supplier mentions 2 to 3 harvests per bucket.
GroCycle (VK) · BS-38Fryslân Fungies (NL) · BS-66If it goes wrong
Green mould in the first week points to coffee grounds that are too old or to poor hygiene: throw it out and start again with coffee grounds from the same day. If colonisation stops halfway and it smells sour, the mixture is too wet or too compact: mix in straw or pellets. Coloured patches always mean: do not eat.
GroCycle (VK) · BS-38University of Florida / IFAS Extension · BS-01Source
- Grow Your Own Oyster Mushrooms at Home (SS662) — University of Florida / IFAS Extension
- Growing Mushrooms in Coffee Grounds — GroCycle (VK)
- Oesterzwam Growkit (emmer + broed, koffiedik zelf toevoegen) — Fryslân Fungies (NL)
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This is general growing information from the sources listed. Always follow the instructions of your kit or supplier. Only eat what demonstrably grows from your own culture of the bought, named species; if in doubt about colour, smell or shape, do not eat it.
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