How to grow Mushrooms

A step by step guide on how to grow various types of Gourmet mushrooms.

Growing mushrooms doesn't have to be difficult. There are many different ways to grow your own mushrooms from lab based grow methods through to low tech methods. In this guide I will lay out some easy ways you can grow your own Oyster mushrooms at home as a hobby which can then easily be scaled up to make a profitable business.

Firstly lets learn a bit about how mushrooms grow. Mushrooms are the fruiting body of a network of white threadlike cells called Mycelium.

Mycelium is the vein like structure that grows under the ground as well as through wood and anything else cellulose based. Mycelium is responsible for the decomposition of the organic matter around us and feeds on the nutrients inside recycling them back into the soil and creating more soil in the process. The Mycelium sends out tendril like fingers searching for more food and expanding its territory. Once the nutrients in its patch are depleted or the Mycelium senses the shift in the outdoor season it will send up mushrooms which once matured will release spores (mushroom seeds) that are spread by the wind or animals. These spores will then germinate and create a new mycelium colony which will grow and start the cycle over again. 

This is the very basic knowledge that we need to know to get started growing mushrooms either indoor or outside. To be able to grow the mushrooms indoor or outdoor, unless you are making a ground based seasonal mushroom patch, we will need to grow the Mycelium in bags full of substrate such as wood pellets or grains like wheat and barley. We call these bags either grain or sawdust spawn bags depending on the substrate within. When these bags are fully white and colonized we open and expose the bags to the correct conditions to induce fruiting and make the mushrooms grow.

This grow guide is for growing Oyster Mushrooms (Pleurotus Ostreatus) in a very simple low tech method using pasteurized straw pellets or hardwood pellets.

For a more high tech method which uses heat treatment to pasteurize each bags please click HERE.

For a guide to creating an outdoor seasonal Mushroom patch please click HERE.

Or read on below for the low tech Oyster mushroom grow guide.

Oyster Mushroom Grow Guide

A list of things that you will need.

Pasteurized straw pellets (available here) or pasteurized hardwood pellets (available here)

Plastic bags or buckets. For buckets use plastic buckets at least 5 litres in size with a lid, for these you will also need the ability to put holes in the buckets with a drill. (drilled and undrilled buckets available here)

For plastic bags it could be lay flat tubing and cable ties (available here) or Unicorn bags (available here) or we have even used large zip lock sandwich bags with success.

Duct tape and micro pore tape ( the kind used in a first aid kit) 

Mushroom Spawn. A minimum of 10% inoculation rate at 100g of spawn per kilo of substrate but for best results use up to 250g of spawn per kilo of substrate. (available here)

Latex gloves or similar, antibacterial hand gel and some sort of scoop. You could even wear a facemask to stop yourself breathing in small particles of straw dust.

Scales (bathroom or kitchen scales would be fine depending on the weight of straw you plan to put into the bags).

Antibacterial spray.(Although as long as everything is super clean this can be avoided for Oyster mushroom cultivation)

A watering can or bucket with litre measurements.

A scoop or strong handled jug. I find plastic measuring jugs tend to break so would recommend the type of scoop you would use for dry animal food.

Lastly you need a big tub to mix it all in and some water (2.2 times the kilo weight of the substrate in litres). So if you had 10 kilos of straw you would multiply that by 2.2 making 22 which would mean you need 22 litres of water to rehydrate the 10 kilos of straw pellets effectively.

In this grow guide I will be referring to straw but the hardwood sawdust blocks work in exactly the same manner with the same rehydration, you could even do mix of the two substrates.

Right then so you have gathered your supplies. Here we go.

Find a good sturdy surface, give yourself plenty of room and pop on those gloves. A quick spritz of hand gel to get rid of those contaminants and grab your scales.

Don't open your spawn bag yet but break up the block into fine pieces to enable you to mix it into the straw effectively.

 In your tub weigh out the desired amount of dry straw pellets say 10 kilos. For this amount you would want to mix in 100-250g of your chosen spawn (10-25% spawn to substrate ratio). Open your spawn bag carefully and weigh out the desired amount before pouring into the tub with the straw. Mix these thoroughly together till the spawn is evenly distributed into the straw.

Measure out your water. This can be in a bucket with litres on the side, a clean watering can or any other way that you are able to track the amount of water you are using. You need to measure out 2.2 times the kilo weight of the substrate in litres. So if you had 10 kilos of dry straw pellets you would multiply that by 2.2 making 22 which would mean you need 22 litres of water to rehydrate the 10 kilos of straw pellets effectively. Pour in the water and leave for at least 20 minutes for the pellets to fluff and rehydrate.

During this time grab your tube bags and make sure you have tied of one end with the cable to create the bag.

Once the straw is rehydrated give it another mix using the scoop and then start filling the bag with the mixture. The mixture needs to be packed down tightly into the bag as much as possible. A 10 kilo mixture could be split across two bags or more of needed depending on the height of the bags you have. When filling the bags make sure you leave yourself at least 15cms maybe a little more at the top so you are able to pull the sides in and cable tie the top closed as well. 

Now you have your inoculated straw log the last step is to poke some drainage holes on the underside bottom of the bag as well 15 to 20 airholes all around the outside of the bag.

The finished bag now needs placing in a dark room at around 20-24c. If growing Oyster mushroom the bags need to be left for 10 to 14 days to fully colonize. Check the bags daily for any signs of molds, colours of contaminants are usually green, red, orange or blue, if any of these are spotted discard or remove the bag from the room to stop it spreading into other bags. Remember we are looking for glorious white mycelium. 

Once the bags are fully white and colonized they need bringing out into fruiting conditions to induce mushroom growth. For Oyster mushrooms unless growing pink or golden Oysters this means bring into autumnal like conditions with plenty of fresh air, light and a good level of humidity.

Temperature should be 14-20c although a wider temperature range is possible for Oyster mushrooms. A humidity level of 80-95% should try to be reached in an indoor environment through the use of a humidifier in the fruiting room.

Outdoor can be a harder place to control the environment but a small greenhouse or plastic polytunnel can be used to maintain a higher level of humidity and also fruiting the bags seasonally in autumn such as you would find Oyster mushrooms in the wild will also allow them to grow in optimum conditions.

Once the mycelium has fully colonized the bag; has used up most of the nutrients in the substrate; senses the shift in the environment and the higher oxygen level it then starts forming primordia. This primordia formation starts of as fluffy white patches of mycelium that form around the airholes in the bag. These will then turn into small mushroom like blobs, commonly known as pinheads, which will grow up into beautiful clusters of Oyster mushrooms. This process usually takes 10 to 14 days before they are ready to harvest.

Now your mushrooms are big and beautiful they are ready to harvest! Cut off the mushroom cluster at the bag with a sharp knife or simply grab the cluster in both hands and gently twist till it pops off.

Leave the bags and within the next 10 to 14 days they should give you another flush of mushrooms and fruit again possibly for a third and fourth time! Growing Oyster mushrooms is a great low tech easy way to have delicious mushrooms for months on end.

Nothing beats the taste of your own home grown fresh Oyster mushrooms!

For a delicious meal why not cook them in with this luxurious Risotto mix.

Find all then supplies you need to grow your own delicious mushrooms HERE.

We also offer complete kits that contain everything you need to grow Oyster mushrooms with our Beginner, Hobbyist and Semi-Pro packages HERE.