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The Blue Oyster

(Pleurotus ostreatus columbinus)

As the name suggests, the main distinguishing characteristic of Blue Oyster mushrooms from others in their genus is their striking blue colour, which transitions from a deep blue to smoky grey as the mushrooms mature. These are a great choice for beginners!

The Mushroom Grow Kit is intended to be grown inside. The Kit contains a bag of hardwood sawdust inoculated with Blue Oyster mycelium and is ready to ‘fruit’ straight from the bag.

Download PDF instructions here.

Blue Oyster


Step 1: Inspect your Mushroom Grow Kit

  • Examine your bag to make sure it is fully myceliated (white all over). If so, then it is ready to start fruiting! However, if you can see areas of brown sawdust that are not myceliated then place your kit in a dark location (~18-24 C), and check it every day until it is all white.

Step 2: Choose a location for your kit

  • When your kit is fully myceliated (all white), choose a location that is bright but out of direct sunlight, at warmer room temperature (~16-18 C), and is well-ventilated to minimize exposure to spores.

Step 3: Prepare for fruiting

  • Keep the bag closed and turn it on its side.
  • Using a knife, gently cut two 5 cm ‘X’s along the side of the bag where the mycelium is touching the bag, with as little damage to the mycelium as possible.
  • Next, gently squeeze as much air as possible out of the bag through the slits and fold the extra plastic bag (part with the filter in it) under the kit and place the kit upright. The fresh oxygen at the slits will signal the mycelium to start producing mushrooms (usually within 2 weeks or so).
  • Spray the sliced area at least once a day until pinning begins.
Step 2
Step 2b

Step 4: Care for your mushrooms

  • Make a ‘Humidity Tent’ to go over your Grow Kit to help create a humid environment for your mushrooms to grow. Get a clear plastic bag (so light can come through) that is large enough to loosely cover the grow kit with enough room for the mushrooms to grow. Cut approximately 10-1.5cm holes to allow for air exchange (CO2 out O2 in) and place it over your grow it.
  • Lift up & replace the ‘Humidity Tent’ 3 to 5 times a day to spray the inside of the tent with water and allow for fresh air in.
  • If your mushrooms start to grow long and stringy, it is usually a sign that there is too much C02 so ventilate the mushrooms more often and/or increase the number or size of holes in the bag. If your mushrooms are drying out, increase the humidity by spritzing more often.

Step 5: Harvest, Storage and Cooking

  • Oyster mushrooms grow in clusters and can generally be ready to harvest between 4 to 7 days after pinning.
  • Harvest your mushrooms before the largest caps in the cluster begin to flatten out and become concave by cutting the entire cluster of at the base with a knife.
  • It is best to cook your mushrooms when they are fresh but they can be stored in the fridge for about a week in a paper bag (not plastic!)
  • You can also dehydrate your oyster mushrooms but they do not rehydrate very well (especially the stems) so best to powder them and use them in a soup or sauce.

Step 6. Second Harvest and compost your ‘spent’ Grow Kit:

  • To attempt a 2nd harvest (not guaranteed), stop spritzing your kit for 3 days, soak it in cold water for 20 min and start again at Step 2! If you can get your kit to fruit again it will produce a smaller flush the second time round.
  • Once you are done fruiting your kit, break up the sawdust/mycelium and put it in your home or city compost or use as a soil amendment in your garden bed.


  • Mushrooms produce airborne spores as they grow. When released from the gills they produce a dusty surface on your grow kit and surrounding area. To reduce exposure fruit your kit in a well ventilated area, use a ‘Humidity Tent’ and harvest mushrooms while they are still young.
  • Always cook mushrooms before consuming.

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