Do you want to grow your own mushrooms at home using wood chips as a substrate? If so, you must know how to sterilize wood chips properly to prevent contamination and ensure healthy mushroom growth.
In this blog post, I will show you the easy and effective ways to sterilize wood chips for growing mushrooms. You will also learn why sterilization is important, what types of wood chips suit, and how to use them afterward.
Let’s get started!
You want to read the related post on how to sterilize a room for growing mushrooms.
Why Sterilize Wood Chips?
Wood chips are a popular and cheap substrate for growing mushrooms, especially for wood-loving species such as oyster, shiitake, lion’s mane, and reishi. Wood chips provide a natural and nutritious environment for the mushroom mycelium to colonize and fruit.
However, wood chips also harbor many unwanted microorganisms, such as bacteria, mold, and fungi, that can compete with or infect the mushroom mycelium. These contaminants can reduce your mushrooms’ yield, quality, and safety. Therefore, it is essential to sterilize wood chips before using mushroom substrate.
Sterilization is the process of killing or removing all living organisms from a material. Sterilizing wood chips eliminates the potential competitors and pathogens that could harm your mushroom culture. This way, you create a clean and favorable condition for your mushroom mycelium to grow and produce mushrooms.
What Types of Wood Chips to Use?
Not all wood chips are suitable for growing mushrooms. You should avoid wood chips from coniferous trees, such as pine, spruce, and fir, as they contain toxic resin and oils inhibiting mushroom growth. Don’t use wood chips from oak, walnut, or eucalyptus trees because they have lots of tannins. These tannins can make the soil too acidic and not tasty for the mushroom mycelium.
The best types of wood chips for growing mushrooms are from deciduous trees, such as birch, maple, poplar, alder, and willow. These wood chips have a balanced pH and nutrient content that are suitable for most mushroom species. You can also mix different types of wood chips to create a more diverse and complex substrate.
You should also choose wood chips that are fresh and clean, without any signs of decay, rot, or insect damage. Avoid chemically treated wood chips to protect mushroom growth and the environment. You can obtain wood chips from local arborists, garden centers, or wood suppliers. Alternatively, you can make your own wood chips by using a wood chipper to chip branches or logs.
How to Sterilize Wood Chips?
There are several methods to sterilize wood chips for growing mushrooms, depending on the equipment, time, and budget you have. Here are some of the most common and effective methods:
Boiling
Boiling is the simplest and cheapest method to sterilize wood chips. You only need a large pot, water, and a heat source. Here are the steps to follow:
- Fill a large pot with water and bring it to a boil.
- Add the wood chips to the boiling water and submerge them completely. You can use a weight, such as a brick or a plate, to keep them underwater.
- Boil the wood chips for at least 30 minutes, stirring occasionally to ensure even heat distribution.
- Drain the wood chips and let them cool down completely.
- Use the wood chips as soon as possible, or store them in a sealed container or bag until ready to use.
Steaming
Steaming is another easy and inexpensive method to sterilize wood chips. All you need is a large pot, a steamer basket, a lid, and a heat source. Here are the steps to follow:
- Fill a large pot with water and bring it to a boil.
- Place the wood chips in a steamer basket and put it over the boiling water. Make sure the water does not touch the wood chips.
- Cover the pot with a lid and steam the wood chips for at least 90 minutes, checking the water level periodically and adding more if needed.
- Remove the wood chips from the steamer and let them cool down completely.
- Use the wood chips as soon as possible, or store them in a sealed container or bag until ready to use.
Pressure Cooking
Pressure cooking is the most effective and reliable method to sterilize wood chips. It uses high pressure and temperature to kill all microorganisms in a short time. However, it also requires specialized equipment, such as a pressure cooker or a pressure canner, and more caution and care. Here are the steps to follow:
- Fill a pressure cooker or a pressure canner with water according to the manufacturer’s instructions. Do not overfill or underfill the water level.
- Place the wood chips in a heat-resistant container or bag that can fit inside the pressure cooker or canner. You can also add some water to the container or bag to increase the moisture content of the wood chips.
- Seal the container or bag tightly and poke some holes on it to allow steam to escape.
- Place the container or bag inside the pressure cooker or canner and lock the lid securely.
- Bring the pressure cooker or canner to the desired pressure and temperature, usually 15 psi and 250°F, and maintain it for at least 60 minutes.
- Turn off the heat and let the pressure cooker or canner cool down naturally. Do not open the lid until the pressure has dropped completely.
- Remove the container or bag from the pressure cooker or canner and let it cool down completely.
- Use the wood chips as soon as possible, or store them in a sealed container or bag until ready to use.
How to Use Sterilized Wood Chips?
Once you have sterilized your wood chips, you can use them as a substrate for growing mushrooms. Here are some tips to follow:
- Choose a mushroom species that is compatible with wood chips, such as shiitake, lion’s mane, reishi or oyster mushroom. You can buy mushroom spawn or spores from reputable suppliers online or offline.
- Mix the wood chips with the mushroom spawn or spores in a ratio of about 10:1 by volume. You can also add some supplements, such as bran, gypsum, or lime, to enhance the nutrient and pH levels of the substrate.
- Transfer the mixture to a suitable container, such as a plastic bag, a bucket, a jar, or a tray, and seal it with a filter or a hole to allow air exchange.
- Place the container in a dark and warm place, such as a closet, a basement, or a garage, and maintain a temperature of about 70°F to 80°F. This is the incubation stage, where the mushroom mycelium will colonize the wood chips.
- Check the container periodically for signs of colonization, such as white, fuzzy, or stringy growth. This can take from a few weeks to a few months, depending on the mushroom species and the substrate conditions. Avoid opening the container or disturbing the substrate, as this can introduce contaminants or slow down the colonization process.
- When the substrate is fully colonized, move the container to a bright and cool place, such as a window, a balcony, or a greenhouse, and maintain a temperature of about 50°F to 60°F. This is the fruiting stage, where the mushroom mycelium will produce mushrooms.
- Expose the substrate to fresh air, humidity, and indirect light to trigger the fruiting process. You can also cut or poke some holes in the container or bag to allow the mushrooms to emerge. You can also mist the substrate with water to keep it moist but not wet.
- Harvest the mushrooms when they are mature, usually when the caps are fully opened, and the gills are exposed. Cut or twist the mushrooms gently from the substrate and enjoy them fresh, or store them in a refrigerator or a dehydrator for later use.
- You can reuse the substrate for another batch of mushrooms as long as it is not contaminated or exhausted. You can also compost the substrate or use it as a mulch for your garden.
Conclusion
Growing mushrooms on wood chips is a fun and rewarding hobby that anyone can do at home. Sterilize wood chips before using them to prevent contamination and promote healthy mushroom growth.
You can sterilize wood chips in various ways, like boiling, steaming, or pressure cooking, based on your equipment, time, and budget.
You can use various wood chips like birch, maple, poplar, alder, or willow, based on your mushroom type and preference. Once you have sterilized your wood chips, you can mix them with mushroom spawn or spores and follow the incubation and fruiting stages to grow your own mushrooms.
This blog post has helped you learn how to sterilize wood chips for growing mushrooms. If you have any comments, please leave them below.
Happy mushroom growing!
