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Grey Oyster Mushroom Information

Grey Oyster (Pleurotus ostreatus)

Grey Oyster mushrooms (Pleurotus ostreatus) are the most common type of oyster mushroom and can be found across the world. This species is very forgiving to cultivate, and a great option for beginner home growers. When the mushrooms first start pinning they’re a lovely dark grey-blue colour that then fades to a light grey as they mature. These mushrooms like a lot of air exchange and will grow large caps under the right conditions. When starved of fresh air they stretch and produce longer stems rather than big fan-like caps (you want to avoid this as the stems tend to be quite tough). They are found either in clusters of smaller mushrooms, or as individual larger mushrooms, with broad, thin, fan shaped caps and crowded gills underneath that run most of the way down the stem.

Fruiting months: Late Autumn, Winter and early Spring

Pinning Temperature: 10°C – 16°C

Pinning Humidity: 95% – 100%            

Fruiting Temperature:  15°C – 21°C

Fruiting Humidity: 85% – 95%

Cultivation Difficulty: Easy                                                                                                  

Fruiting Instructions

Grey Oyster mushrooms fruit easily and readily. 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 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!

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 highly effective to help create the optimal humid environment for your mushrooms and we recommend using it to 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.

Grey Oyster Tip: The Grey Oyster mushroom likes a lot of fresh air so we recommend using our countertop or macramé fruiting chambers to provide optimal fruiting conditions for this species. 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.


Like the other oyster mushroom species, these mushrooms should be harvested just before the edges of the caps start to curl up. A good sign to watch for is for the curling up of the cap edges on the largest mushrooms in the cluster – as soon as they do this, harvest straight away.

  • Grey oysters should be harvested all at once in their clusters.
  • Wash your hands with soap and water before harvesting
  • Lightly grip the base of the cluster and with a twisting and pulling motion carefully separate the mushrooms 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.

These mushrooms have a longer shelf-life than the pink and golden oyster species, but it is best to cook them within a few days of harvest.

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

Grey Oyster mushrooms have a slightly sweet taste, with a woodsy characteristic. Compared to the shiitake mushroom they have a milder and more tender flavor profile. They are versatile and can substitute well into many mushroom recipes. They are a fantastic meat replacement in stir-fries. In preparation, the stems of these mushrooms should be cut away, as they are tough even when cooked. Grey Oyster mushrooms go particularly well in egg dishes like omelets or quiches and are a delicacy often used in Japanese, Korean and Chinese cuisine. Once cooked they have a pleasing and tender texture, especially when fried, roasted, or grilled. Braising and sautéing will bring about a softer texture.

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