Short answer: King oyster likes it cool: 10–15 °C at the start, then 12–18 °C. Press the bag down onto the block, put a rubber band around the bag right above the block and make a 5–7 cm slit at the top, just below the seal. Spray twice a day. As soon as the first small mushrooms appear, cut off the top of the bag and leave about 10 cm of bag wall. Harvest after about 8–13 days, when the caps start to flatten.
This is the guide for The Block in the king oyster variety (Pleurotus eryngii). It is opened differently from oyster mushrooms: not with a cross on the side, but at the top.
Difficulty: Intermediate. It needs cool temperatures, and you open the bag with the rubber band method.
Other varieties: Blue oyster · Phoenix oyster · Lion's Mane · Shiitake
What you need
- The Block: substrate of oak sawdust and wheat bran, without chemical additives, colonised by king oyster mycelium
- The spray bottle that comes with it
- Clean scissors or a sharp knife
- A rubber band
- A bright, cool spot without direct sun, for example a hallway, cellar or a barely heated room
Step 1: Unpack and check
- Unpack the parcel straight away. The mycelium is alive and needs air. Please don't tape over the small filter on the bag: it lets air through and keeps spores and germs out.
- Look at the bag. If it is completely white, you can start. If you still see brown patches, leave it closed at room temperature until it is white all over. That usually takes just a few days.
- If small mushroom buds are already growing inside the bag, start right away.
This is normal: yellowish drops in the bag, small yellow or brownish spots in the mycelium and a fresh, mushroomy smell.
Step 2: Find a cool spot and open the bag
King oyster likes it cool: 10–15 °C at the start, then 12–18 °C, ideally 13–16 °C. Put the block somewhere bright but out of direct sun, not next to a radiator.
King oyster gets no cross cut on the side. This is how you open the bag:
- Press the bag down onto the substrate and put a rubber band around the bag as close above the block as possible. This keeps air away from the sides, so no mushrooms grow there.
- Make a 5–7 cm slit at the top, just below the seal. The fresh air triggers bud formation, while the bag keeps the moisture in.
Step 3: Keep it moist and cut off the top of the bag
Spray through the slit twice a day and pour off any standing water on the block. The first small mushrooms appear after about 5–14 days.
Then cut off the top of the bag. Leave about 10 cm of bag wall above the block so the surface doesn't dry out. Keep spraying twice a day and pour off puddles.
Tip: Air the room regularly. Without enough fresh air the mushrooms grow long, thin stems.
Step 4: Harvest
Harvest after about 8–13 days, when the caps start to flatten and growth slows down. Cut the mushrooms close to the substrate.
Step 5: Second flush
After harvesting, remove stem remains and keep the surface moist, but without puddles. A second flush usually follows after about 14 days.
At home this doesn't always work. The first harvest uses up much of the water and nutrients in the block. In our production we control humidity, temperature and fresh air. At home the air is often drier and the temperature varies more, so the opened block dries out faster. Mould spores and small flies from the room also reach the substrate through the opening. So don't worry if your block gives only one good harvest.
If something goes wrong
- No buds after 2 weeks: Move the block somewhere cooler and brighter, ideally between 10 and 15 °C, and spray regularly.
- Mushrooms grow on the side of the bag: Air is getting in there. Put the rubber band as close above the block as possible and press the bag down firmly.
- The surface dries out: Leave about 10 cm of bag wall and spray more often.
- Water is standing on the block: Pour it off. King oyster doesn't like waterlogging.
- Green or black spots: This may be mould. Please send us a photo at team@meisterpilze.de or via WhatsApp +49 157 54040209.
Safety
- When cutting with scissors or a knife: children only under adult supervision.
- Mushrooms release spores while fruiting. Don't let the block fruit in a bedroom and air the room regularly.
- Eat mushrooms only cooked.
Frequently asked questions
How long does it take? Usually one to three weeks from opening to harvest.
Why do I need a rubber band? Without it, air reaches the sides of the block and side buds form there. With the rubber band the mushrooms grow at the top, where they are easy to harvest.
My room is warmer than 18 °C. Will it still work? King oyster likes it cool. Look for a cooler spot such as a hallway or cellar. For warm rooms, Phoenix oyster is the better choice.
Why do I harvest less than you do in your production? The Block uses the same recipe as our own production. But perfect conditions are harder to create in a living room or kitchen, so the harvest is sometimes smaller. Watching everything grow and eating the mushrooms really fresh is still worth it.
What do I do with the block when it's finished? The spent substrate is a good soil improver for compost, raised beds or the garden. It often even produces a few more mushrooms there, especially in autumn and spring in a spot without direct sun. Pouring some water over it or soaking the block for a few hours helps.
Our promise
If no mushrooms grow for you, we'll send you a new block. Just write to us with a photo of your kit at team@meisterpilze.de or via WhatsApp +49 157 54040209.
Have fun and good luck! Your Meisterpilze team from Erlangen