How to Grow Oyster Mushrooms

How to Grow Oyster Mushrooms

Growing Italian & Pink Oyster Mushrooms

In this guide, we will cover how to grow oyster mushrooms! Italian and Pink Oyster mushrooms are a staple for the hobby mushroom grower. Easy to cultivate and forgiving of any mistakes. They grow quickly, you can have a fresh harvest of oysters on your plate in just a couple of weeks!  There are many different types of oysters, but here we will focus on the Italian and Pink oyster. These both produce excellent mushrooms that are some of the tastiest you will find. Growing mushrooms at home has never been easier. 

Once the Oyster block is fully colonized it will be ready to fruit!

We want to separate fruiting oyster mushrooms into three steps. The first is opening the block, the second is primordia formation, or 'pinning'. The third is fruiting.

Step 1 – Opening

When you have a fully colonized bag, you need to cut an ‘X’ in the side of the bag. Prep the mushroom block by wiping the front face and a razor blade or shape knife with alcohol-based hand sanitizer. This will remove any bacteria which can grow on the substrate.

This ‘X’ needs to be about 5x5cm.  Like most oysters, these species are a prolific fruiter, and opening the entire block to the atmosphere will cause far too many pins sets (small mushrooms) and a waste the energy in the block.  So, we need to direct the mushrooms where to grow.  As mentioned above this is done but cutting an ‘X’ in the side of the bag directly over the substrate. When the fresh air and humidity hit the exposed substrate under the cut, primordia or pins should form there.


pink oyster mushrooms growing in a mushroom fruiting room
Pink oyster mushroom growing from Oak and Spore Mushroom Kits and some Oak and Spore Commercial Grow Blocks. These were grown in winter, when the inside of the fruiting room got very cold and humid. It causes the edges of the mushroom to curl up prematurely. It can be avoided to decreasing the humidity on cold nights. 


Step 2 - Primordia Formation

To form primordia, or 'pins' you need to provide the block and the opening with four elements.

Light, humidity, fresh air exchange, and the correct temperature.


Light - Contrary to popular belief, mushrooms need a bit of light to grow. Good old fashioned natural light!  But do not leave it directly in the sun.  Indirect diffused sunlight is best. It should have around 12 -14 hours of light a day. Mushrooms won't grow in your dark closet!


Humidity - During primordia formation, the oyster blocks like it close to 100% humidity  If you are using a small fruiting chamber, or simply fruiting your block in the bathroom or kitchen bench, and do not have a pond fogger and/or humidifier,  with a small spray bottle you will need to ensure you, with water,  lightly mist or spray the ‘X’ in your block 3-5 times per day. This can be done every time you wash your hands in the bathroom. Be careful not to over water and the area, the ‘X’ should be no more than moist, do not soak. moist, the area you spray creates a little micro climate of humidity to entice a good pin set.


Fresh Air Exchange (FAE) - Mushrooms love to create CO2, they are masters at it. If there is too much CO2, they just won't fruit.  To prevent this, we need to ensure there is plenty of fresh air moving around the oyster block.  If you have your block in a room like the bathroom, cracking open the window will help.  If the CO2 content is too high, the mushroom will tell you by growing really long stems as they search for fresh air. Don’t be too concerned about the fresh air requirements unless you are getting mushrooms with long stems.  Just crack a window!


Temperature - Oysters like a mild temperature, and pink oysters prefer a more tropical temperature. Between 16-24 is great for Italian oysters. You will find pink oysters do not like to grow below 15 degrees.


Step 3 - Fruiting

This is the part you have been waiting for.

All going well, you've provided your block with the perfect conditions and have some good pins growing.  Now is the time to take them through adolescence into maturity.  At this time the humidity can be dropped slightly back,  but still needs to be high. Over 80% is good.  The temperature should remain between about 16-20 degrees.  Try to keep the humidity and temperatures constant during this stage and the oyster should form.  To do this we can continue to lightly spray the mushrooms to ensure they have some humidity.

If you leave the Italian Oyster to grow, they will become huge. I like to pick them before they get too large, when they are just perfect size to fry them with some eggs and toast!  Once picked, place the mushrooms in a 1- degree environment (i.e., the fridge) as quickly as possible.  If stored correctly, your oysters can last up to 10 days!  We suggest using a paper bag when in the fridge.

Step 4 - Repeat the Process

After you’ve harvested, use a clean knife and cut away and excess mycelium.  Again keep spraying the exposed substrate with water a few times a day, and in about a week you should get a second crop of mushrooms. You'll be surprised just how many mushrooms will grow from a single block.


Fruiting Italian & Pink Oyster mushrooms is a fun and exciting way to grow your own mushrooms.  They fruit quickly and within a week or two you can have fresh oyster mushrooms on the dinner plate!