King Oyster Mushroom Kit Instructions
King Oyster mushroom is a delicious, meaty mushroom that is native to the mediterranean and popular in Asian cooking! King oyster mushrooms form large beautiful 'trumpets' that will grow inside the fruiting bag which is fitted with a special micro-filter patch, allowing some gas exchange but inhibiting moisture loss and competing organisms.
Each species of mushroom is a different growing experience. Even if you have grown mushrooms before, please read the instructions for your kit carefully before proceeding. If you run into any problems please see our FAQ.
Step 1: Mycelium Check
Inside this box mycelium has has been happily breaking down the organic growing medium and converting it into energy. At first the mycelium is often wispy and hard to see, but as it gets ready to produce mushrooms it becomes more dense and white in colour.
Open the box and remove the bagged block of mycelium and growing medium.
Mostly brown with some white =
needs more time in a warm location
Mostly White =
ready to move on to stage 2
Entirely White =
ready to move on to stage 2
If your block is brown:
Unroll the bag and move your block to a warm, dark location - over 15°C and NO MORE THAN 25°C. Do not place it near any heat sources such as a radiator, as this will cause it to overheat. Check it once a week until at least 60% of block is covered with white mycelium.
If your block is covered with over 60% white mycelium:
You can now move on to step 2.
If you do not want to move on to step 2 at this time, you can keep your kit in the fridge or a cool place for up to two weeks.
Step 2: Finding and creating ideal conditions
King oyster mushrooms grow best when they are out of direct sunlight and have plenty of humidity and some fresh air exchange. Finding and/or creating the perfect environment is key to getting the most mushrooms out of your kit.
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Find a place in your house that it out of direct sunlight.
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If you've purchased a thermometer/hygrometer, a temperature reading between 12°C and 17°C is ideal.
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Do not enclose your kit in a box or cupboard as oysters need access to fresh air or they will not grow properly.
Step 3: Initiating Fruiting
Cut an X-shaped slit in the plastic
Find the side of the bag that rests directly against the wide side of the mycelium block (see image below).
Use a clean knife or scissors to cut a large “X” into this area of the clear plastic only. each line of the “X” should be between 3-4 inches long.
Important: Do not cut through the white filter patch or any part of the bag not in direct contact with the mycelium block. You want to expose the mycelium to air as this is where the mushrooms will grow.
Keep the plastic in place
Do not cut away any plastic from the slits in the bag. The plastic helps keep the block moist around the slits, which is essential for mushroom growth. The mushrooms will push through as they develop.
Position the block correctly
King oyster mushrooms are “top-fruiters,” meaning they prefer to grow upward. Position the block so the X-shaped slit is facing up.
Make sure the bag stays snug
The plastic should remain tightly wrapped around the block. If the bag is loose or open, mushrooms might start pinning inside the bag, where they won't get enough air and will not develop properly.
Note the size of the cross. The block will need to be flipped so that the cut is facing upwards. The mushrooms will grow upright from this opening.
Step 4: Misting & Fresh Air Exchange
King Oyster Mushrooms prefer to grow in an environment with 80-90% humidity. Because of this, you'll need to gently mist your kit regularly with a clean spray bottle. You want to create a humid environment for the mushrooms and to keep their bodies moist.
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Mist the opening you've cut in the bag 1-2 times daily and keep a close eye on it.
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As soon as you spot the first signs of the mushrooms pinning, increase the misting to 2-4 times a day to keep the growing mushrooms from drying out.
Step 5: Pinning
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'Pinning' should begin within 5 weeks of initiating fruiting. If you haven't seen any pinning after 5 weeks please see our FAQ. If the weather is especially warm, you may need to cold shock your block in the fridge for 24-48 hours. Once they have begun to pin, your mushrooms will grow rapidly. Keep the mushrooms moist during this period.
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Increase your misting to at least twice a day (you may need to do so more frequently depending on your environment), making sure the keep the fruit bodies moist by misting very generously.
King oyster pins growing from the slit in the bag.
Step 6: Harvest
Harvest your mushrooms before the edges of the caps begin to either flip up or to wrinkle, darken and split. A white dust under your mushrooms means they have started to drop spores.
Your mushrooms will be at their most tender if you harvest them before they drop spores, but they'll still be perfectly delicious if you don't quite catch them in time.
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When your mushrooms reach the desired size, harvest them by twisting and pulling each one off at the base. Avoid cutting, as leaving the stem attached to the growing medium can hinder mycelium growth and encourage mold. Make sure to harvest all mushrooms, including any small pins, from the first flush before attempting a second, as leftover mushrooms can inhibit new growth.
Step 7: Initiating The Next Flush
King oyster mushrooms will generally yield 1-2 flushes, with 4-9 weeks between flushes. To attempt a second flush of mushrooms try the following:
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Make sure you have harvested all mushrooms and removed any fruiting body remnants.
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Soak your block: fill your growing bag with enough tap water to cover your block and soak for no longer than 1 hour. Make sure to drain away excess water thoroughly after soaking.
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Cold shock: store your block in the fridge for 24-48 hours. The change in temperature can help trigger fruiting.
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After giving it a soak and cold shock, you can return your kit to your chosen location and continue from step 4.
Step 8: What to do with your kit when it stops producing mushrooms
Did you know that fungi play a key role in storing carbon? Trees and plants remove carbon from the atmosphere and fungi break down plant waste to create new carbon-rich soil. Clean air, healthy soil and delicious mushrooms: just one of the many ways fungi are incredible!
Once your box has finished flushing, open the box and remove the mycelium block from its plastic bag. Discard the bag in the general waste. You can now recycle the box and additional packaging and compost the block.
Alternatively plant it in the garden to see if it will gain a some energy and produce one last seasonal crop for you! Simply dig a hole in a shady spot, bury the block and cover it over with around 5cm of soil. Water it occasionally to keep the soil moist.
We hope you've enjoyed growing your King Oyster mushrooms!
We're passionate about sharing the diversity of the fungi kingdom & making more of its delights easy to grow. Want to try another strain or learn how to cultivate mushrooms? See our full range of mushroom growing kits and cultivation workshops!