Direction to grow:
150–250g spawn to 700g dry straw pellets for 3.5L buckets
50g spawn to 250g dry straw pellets for 1kg yoghurt pots
Dry mix the spawn and dry straw pellets in the container.
Add water: 2.2L per 1kg of dry pellets. Add 1st half of water then wait 15 minutes for pellets to partially rehydrate before adding the 2nd half of the water. This ensures the pellets at the top of the container also soak up the water. Remember that the drainage hole should be covered for this! This is why the double bucket system is useful. Alternatively, use tape to cover the hole temporarily, or drill the hole after rehydration.
Close the container. Let sit for between 2–8 weeks. Provide a dark humid environment. This can be done using several methods:
• Double bucket method as described above
• Put entire container into a plastic bag with a stick on top to provide some air flow around the container. This allows some evaporation and helps prevent stagnant water and an anaerobic environment.
• Mist the openings daily if not enclosed.
• Put containers in a green house or cupboard to increase humidity.
The spawn run is fascinating. Within a few weeks, you should see white mycelium colonising the substrate. Several sources say not to disturb the mycelium too much during the spawn run. This is probably wise as every intervention introduces other spores and microorganisms in the environment to the closed container. The substrate is fully colonised when there is an almost solid white mat visible and the substrate is almost no longer visible. It is then ready for fruiting. The timing to remove the outer bucket or uncover the lid is not entirely fixed. Some sources say to wait for a completely white mat, while others keep their containers uncovered during the entire spawn run and just provide a humid environment. Still others use plastic bags and slit them when read to fruit.
Once the substrate is fully colonised, it is time to induce fruition. Several factors are required for good fruiting, but even within literature, not everything is fully understood about it. Known factors:
• Lowering of CO2. This is achieved by opening the bucket/container
• A bit of sunlight
• Mild drop in humidity from close to 100% to around 70%. This is controlled in commercial enterprises but for the backyard mushroom maestro, keeping it in a greenhouse or similar is sufficient. Occasional misting with water may prevent mushrooms from drying out.
• Increase in fresh air flow. My greenhouse has riveted holes in the top and bottom to allow this, I also leave the flap unzipped but down sometimes. Leaving it completely open will attract flies.
In a few days to a week, you should start to see pins. These are the initial heads of mushrooms which will expand and grow to full size. Keep a close eye on them during this time. In a greenhouse, the time from pin to harvest can take 1–2 days, but may take up to a week otherwise. Maintaining humidity is important to prevent mushrooms themselves from drying out, but too much moisture will encourage other moulds and undesirable microorganisms.
Your oyster mushrooms are ready just before the caps turn upwards. This is when they are largest but also firmest. After their caps turn upwards, they get less firm and start to drop spores.
Cut the entire cluster of mushrooms with a knife, or if they are growing out of holes on the side of your bucket, twisting them off is also possible.
