Oyster Mushroom Cultivation with Straw for Growers of Any Size 

Oyster Mushroom Cultivation with Straw for Growers of Any Size 

Discover a method for oyster mushroom cultivation that uses straw and you can begin growing your own oyster mushrooms at home or commercially

Today we are going over some information for oyster mushroom cultivation on straw. This is a popular method that many growers use. We break down this process into six steps, and then discuss four different ways of treating the straw to be ready for inoculation. If you want to grow your own oyster mushrooms at home or commercially using straw, you will need a few materials. Obviously, straw is one of them. Oyster mushroom grain spawn is another. You can check out our selection on our grain spawn page. The information below also shares some other materials you will need.

Oyster mushroom cultivation using straw

Oyster mushroom cultivation on straw can be broken into four parts: treatment of the straw, inoculation, incubation, and fruiting. Each step is crucial to the next and affects the overall yield. The step-by-step process of growing oyster mushrooms on straw is outlined below.
  1. Chop straw: By chopping the straw the cell walls of the straw are broken making it easier for the oyster mycelium to access the nutrients in the straw. Chopping the straw makes the particle size smaller allowing a more compact substrate. A relatively small gap of 1-2 inches between pieces of straw is like the Grand Canyon for mycelium to grow over. Energy and time is wasted as the mycelium tries to grow over these sorts of gaps. Air pockets can be minimized and yield increased by chopping the straw and firmly packing the bags with it.
  2. Treat straw: Using the method which best meets the needs of the grower the straw is prepared for the oyster mycelium. By treating the straw microorganisms are killed and competition for the available nutrients is limited.
  3. Inoculate: Add spawn into the treated straw. This is the material used to introduce the mushroom mycelium to the new substrate.
  4. Incubate: Incubation should ideally occur at 75 degrees F for about three weeks depending on the inoculation rate. By placing bags at least a palm’s distance from one another you can limit overheating.
  5. Fruit: There are 4 parameters to be aware of when fruiting. They are light, humidity, temperature, and CO2 level. For most oyster mushrooms a well-lit room at 85-90% humidity, 65 degrees, and CO2 below 800 PPM is ideal.
  6. Harvest: Harvesting typically occurs about 5-10 days after the substrate is moved into fruiting conditions. Mushrooms should be harvested before the caps completely flatten out.

Four ways of treating straw for oyster mushroom cultivation oyster mushroom cultivation

  1. Hot water pasteurization: Using a 55 gallon drum raised up on cinder blocks and a turkey burner below about 30 gallons of water is brought up to 180 degrees F. Two burlap sacks of straw are then submerged in the barrel and the heat is turned off. A top is placed on top of the barrel and the water is maintained above 145 for two hours. We did not need to turn the heat on after submerging the straw in 180 degree F water. (figure 10)
  2. Hydrated lime: Soak 2-3 burlap sacks of straw are placed in a 55 gallon barrel. 1 Gallon of hydrated lime is mixed with water in a 5 gallon bucket, the lime is dissolved and slowly added to the 55 gallon drum as it is filled with water. The barrel is filled until the straw is completely under water and the solution is at a pH of 12-13. The straw is left to soak for 16 hours. It is critical to use hydrated lime with magnesium content below 10%
  3. Cold fermentation: The straw is submerged in a 55 gallon barrel of water for 5-8 days until the smell of fermentation is apparent.
  4. Wood ash soak: This method is the same as the hydrated lime soak but instead of using lime wood ashes are used. We found it difficult to bring the pH to the necessary level using wood ashes. Close to 4 gallons of ashes was used for a 55 gallon barrel raising the pH to about 11. The straw was allowed to soak for 16 hours.
In pasteurization, which is the standard for straw treatment, the temperature is raised to kill all of the mesophilic organisms but not reach temperatures to activate the thermophilic organisms. By killing the mesophilic organisms the mushroom mycelium has a clean substrate to grow onto. With the lime soak and wood ash treatment the pH spikes and bursts the cell walls of the microorganisms. Once the straw is drained the pH lowers back to 7, which is a suitable place for mycelial growth.

Interested in oyster mushroom cultivation but don’t want to use straw? We have some ideas for you

You can also use woodchips, coffee grounds, or even toilet paper to cultivate oyster mushrooms. Remember, oysters are some of the easiest mushrooms to grow. Take a look at this article that discusses using coffee grounds and toilet paper for oyster mushroom cultivation at home on a small scale. Another great way to do it is with our oyster mushroom growing kits, which come ready-to-fruit and typically produce a flush of fresh mushrooms within two weeks of starting the kit.
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