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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.


Brown or Brown & 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 dark location - over 15°C and NO MORE THAN 25°C. 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.

  • Find a place in your house that it out of direct sunlight. If you've purchased a thermometer/hygrometer, a temperature reading between 12°C and 17°C is ideal.​

  • Do not enclose in a box or cupboard as oysters need access to fresh air.


  • Your mycelium block comes in a grow bag with a breathable micropore filter patch to help facilitate gas exchange. You will grow your mushrooms inside of this bag to help keep humidity up and pests and competing organisms out.

Step 3: Initiating Fruiting


  • Cut open the grow bag along the top edge.

  • Create enough room for your mushrooms to grow inside the bag.

  • Roll the top of the bag down and seal with clips.

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. They also require access to oxygen and fresh air exchange. Because you are beginning to grow your mushrooms inside of the growing bag, you will need to add some fresh air to your kit regularly.

  • Once per day, open the top of the bag and spray generously and fan in fresh air for 1 minute. ​

  • Keep a close eye on the top of the substrate. As soon as your mushrooms begin to pin, you will want to move on to Step 5.

Step 5:  Pinning and Increasing Fresh Air Exchange
  • Once you begin to see tiny pins on the surface of your substrate you will need to increase the fresh air exchange by rolling down the top of you bag like the photo above. 

  • Increase your misting tow twice a day, making sure the keep the fruit bodies moist. 

'Pinning' should begin within 5 weeks of initiating fruiting. If you haven't seen any pinning after 5 weeks please see out FAQ. Once they have begun to pin, your mushrooms will grow rapidly. Keep the mushrooms moist during this period. 

  • Once fresh air exchange has increased pinning should develop rapidly. Not all pins will develop into full grown mushrooms.

Step 6: Harvest

Harvest your mushrooms before the edges 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 sporate, but they'll still be perfectly delicious if you don't quite catch them in time.


  • When your mushrooms have reached the desired size, harvest them. To harvest, twist and pull each mushrooms off at the base. Do not cut them as leaving the stem attached to the block of growing medium can inhibit the growth of your mycelium. Be sure that you have harvested all mushrooms from your first flush before you attempt a second. 

Step 7: Initiating The Next Flush

King oyster mushrooms will generally yield 1-2 flushes. To attempt a second flush of mushrooms try the following:


  • Make sure you have harvested all mushrooms and removed any fruiting body remnants. 

  • Fill your growing bag with enough tap water to cover your block and store your block in the fridge for 12-24 hours.


  • Drain away excess water, replace the paper clips and resume 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. Alternately  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!

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