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King Oyster Mushroom Growing Guide

King Oyster (Pleurotus eryngii)


The King Oyster (Pleurotus eryngii) is a large, heavy mushroom with meaty stems that are the star of the show. Unlike other oyster mushrooms, King Oysters have a much longer shelf life and can be kept in the fridge for up to two weeks after harvesting.

With a mild flavour that is well suited to seasoning, this mushroom is extremely popular in the culinary world. Their meaty texture is sometimes compared to abalone or scallops.

Under the right conditions, the King Oyster produces a well-defined stem with a round cap. They tend to fruit singly and be rather large and heavy, with thick meaty stems. The thick stem is what this mushroom is desired for in the culinary world. Unlike the other oyster mushrooms, the ideal conditions required for King Oysters to grow with thick stems and small caps is to reduce the amount of fresh air available. For this reason you must be very careful about the placement of your grow stick and fruiting chamber – make sure there is as little draft as possible and keep it in the coldest room in your house.

Fruiting months: Winter

Pinning Temperature: 10°C – 15°C

Pinning Humidity: 95% – 100%

Fruiting Temperature:  15°C – 21°C

Fruiting Humidity: 80% – 95%

Cultivation Difficulty: Medium

Fruiting Instructions

King Oyster mushrooms fruit easily provided the correct conditions are provided. Various methods can be employed to fruit them successfully, the following is a tried and tested guideline:

Step 1: Remove the cotton wool plug from the grow stick and fill the hole with a small amount of water. After a few minutes you can pour it out.

Step 2: Cut an X-shape (fruiting site) in the plastic at your chosen spot (see below for a tip!). Each cut should be roughly 5cm long. Don’t cut more than one X and make sure to use a sharp knife or pair of scissors.

Tip: Often pins have already formed under the plastic and look like small bumps or bulges. These are good spots to choose for the next step. If there is no sign of pins forming, try to make your opening close to the hole of the grow stick. 

Step 2: Cut open the plastic at your chosen spot (see the tip below!). Cutting an “X” shape is the best, because it’ll keep your pins a bit covered and therefore keep their environment sufficiently humid. You can also just cut the plastic away completely and expose the mycelium, but make sure you keep the exposed area wet enough.

Tip: Often pins or overlay has already formed under the plastic and look like small bumps or bulges. These are good spots to choose for this step. If there is no sign of pins forming, it is best to wait (up to a week) to see if you get any overlay or pins forming under the plastic. If you still don’t see any pins, you can try cutting at a spot that has a lot of concentrated mycelium. Make sure this spot is close to your soaked perlite, and keep it well hydrated (especially with this species!)

Optional Step 3: Put your perlite in a colander or sieve and run some cold water over it before adding it to your fruiting chamber. Once it’s in the chamber, you can even add a little extra water to make sure it’s soaked through.

Tip: Soaked perlite is extremely useful to help create the optimal humid environment for your mushrooms and we recommend using it to help you get the best results from our grow sticks. We supply perlite with all our fruiting chamber options but it is also readily available at most nurseries.

Tip: The King Oyster mushroom likes limited fresh air so we recommend keeping it in a closed off room while fruiting. If you do not have one of our fruiting chambers you can use a plastic tray or plate instead.

Step 4: To avoid possible contamination, clean your chosen fruiting chamber with soap and water, rinse it thoroughly and let it dry.

Step 5: Place the grow stick in your chosen fruiting chamber. Make sure that your fruiting site is positioned so that your mushrooms will not be obstructed by any part of the fruiting chamber as they grow, and that they are as close to the water or soaked perlite as possible.

Tip: Consider carefully where you place your mushroom kit as this will affect how well they grow. Try to find a spot that receives plenty of ambient light but is out of direct sunlight. Avoid drafty areas such as those next to open windows or doors as this can dry out the growsticks. A closed off room that has a regular temperature is best.

Step 6: Using a spray bottle set to a fine mist, spray your grow stick from about 30cm away.  Misting 2 – 4 times per day is enough to keep your mushrooms happy! Before work, when you get home, and just before bed should be sufficient but an extra misting would be beneficial if you’re at home.

Tip: Try to spray so that the mist falls over the grow stick and perlite rather than spraying directly at the mushrooms. It’s ok for the mushrooms to get slightly wet but remember that the aim of misting is to maintain a humid environment for them. Use your mister to rehydrate the perlite if it feels dry, and don’t be afraid to add some more water to the perlite at any stage.


When to harvest is up to the cultivator’s preference, although younger King Oysters do tend to have a better flavour and texture. The stem should at least be allowed to grow nice and thick, as it is the star of this species. King Oysters have a much better shelf life than other Oyster Mushrooms and can be kept in the fridge for up to two weeks after harvesting.

  • King oysters grow as individual mushrooms.
  • Wash your hands with soap and water before harvesting
  • Lightly grip the base of the mushroom and with a twisting and pulling motion carefully separate the mushroom from the substrate of the grow stick.
  • Try not to take too much substrate off of the grow stick.
  • Tape up your hole with some clear packaging tape as neatly as possible with as little chance for air to enter the gaps.
  • Check out our guide on how to get a second flush out of your grow stick – The Second Flush.

Caution: If you let your mushrooms grow too long before harvesting they will drop spores. When your mushrooms drop spores it dramatically decreases their quality and it can be dangerous to your lung health if this happens too often.

Culinary Notes

Said to be “the best tasting Oyster mushroom”, the King Oyster is a wonderful culinary delight. Their meaty texture is sometimes compared to abalone or scallops and are often sold as “mushroom steaks”. They have a mild flavour which allows them to easily take on stronger flavours like soy sauce or garlic. Due to their popularity, there are loads of recipes all over the internet. A few interesting ones include: Pulled “Pork” Sandwich, King Oyster Skewers and Vegan Scallops.

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