Mushroom Composting: A Complete Guide in 2024

Mushroom Composting: A Complete Guide in 2024

What is Mushroom Composting

Mushroom composting is a process of creating a nutrient-rich growing medium specifically designed for growing mushrooms.

It involves the decomposition of organic materials, such as straw, hay, corn cobs, cottonseed meal, and gypsum, using a combination of beneficial microorganisms and mushroom spawn.

The end result is a nutrient-rich substrate that provides the perfect growing environment for different varieties of mushrooms.

Other Uses of Mushroom Compost

  1. Soil amendment: Mushroom compost can be added to the garden soil as a soil amendment. It is rich in nutrients and organic matter, which helps to improve soil structure, water retention, and fertility. It also helps to suppress soil-borne diseases and pests making it an excellent choice for organic gardening.
  2. Potting mix: Mushroom compost can be added to potting soil as a component of the growing medium. It provides an extra source of nutrients for plants and helps to improve soil aeration and drainage.
  3. Mulch: Mushroom compost can be used as mulch for garden beds, trees, and shrubs. It helps to suppress weeds while retaining moisture in the soil.
  4. Erosion control: Mushroom compost can be used to control erosion on slopes and other areas prone to erosion. It helps to hold the soil deeper in place.

What is Mushroom Substrate

Mushroom substrate is simply a growing medium for mushrooms. It is a combination of nutrient-rich organic materials that provides an ideal environment for the mushroom mycelium to grow and develop into mature fruiting bodies. The substrate is typically made up of a blend of materials such as straw, sawdust, wood chips, corncobs, cottonseed meal, and other agricultural waste products.

Mushroom substrate can be purchased pre-made or can be prepared at home using a combination of organic materials and mushroom spawn. The substrate is typically sterilized or pasteurized to kill any unwanted organisms and to create a sterile environment for the mushroom mycelium to grow. Once the substrate is colonized with mycelium, it is ready for the fruiting stage, where mature mushrooms can be harvested.

Who Sells Pre-Made Mushroom Compost

How to Make Mushroom Compost at Home?


  • Straw or hay
  • Corn cobs or other agricultural waste
  • Cottonseed meal or soybean meal
  • Gypsum
  • Water
  • Mushroom spawn


  1. Chop the straw or hay into small pieces and add them to a large container.
  2. Add the corn cobs or other agricultural waste to the container.
  3. Mix in the cottonseed meal or soybean meal and gypsum.
  4. Add water to the mix until it is moist, but not wet.
  5. Place the mix near a heat source and use a thermometer to check the temperature of the mix. It should be around 140-160°F.
  6. Cover the container and let the mix pasteurize for several hours. The pasteurization process will kill any unwanted organisms while preserving the beneficial microorganisms that will help decompose the organic matter and support mushroom growth.
  7. After pasteurization, let the mix cool down to room temperature.
  8. Add mushroom spawn to the mix and mix it thoroughly.
  9. Transfer the mix to plastic bags or containers for growing.
  10. Keep the bags or containers in a warm, humid environment with proper ventilation and lighting to encourage mushroom growth.
  11. Monitor the moisture levels of the compost and mist it with water as needed.

It is important to note that making mushroom compost at home requires careful attention to hygiene to prevent contamination. The composting process can also generate heat, so it is essential to monitor the temperature to avoid overheating.

Plants that are most suitable for mushroom compost

Mushroom compost can be used to fertilize a wide range of plants, as it is a nutrient-rich growing medium that provides a good source of organic matter and beneficial microorganisms. However, some plants are more suitable for mushroom compost than others. Here are a few examples:

  1. Vegetables: Vegetables such as tomatoes, cucumbers, peppers, and eggplants thrive in mushroom compost as it provides them with the essential nutrients they need for healthy growth.
  2. Fruits: Fruits such as strawberries, melons, and raspberries also benefit from mushroom compost as it improves soil structure and fertility, and enhances the flavor and yield of the fruit.
  3. Flowers: Many flowering plants including roses, dahlias, and chrysanthemums, benefit from mushroom compost as it promotes healthy root growth and enhances flower color and size.
  4. Herbs: Herbs such as basil, parsley, and cilantro grow well in mushroom compost as it provides the nutrients they need for healthy growth and flavor.

When using mushroom compost as a fertilizer, it is essential to mix it into the soil thoroughly and use it in moderation. Excessive use of mushroom compost can cause nitrogen imbalances and lead to plant damage. It is also important to avoid using mushroom compost on plants that prefer acidic soil, as it can raise the soil pH levels.

Alternative Mushroom Composts

There are several alternative mushroom composts that can be used instead of traditional compost made from straw, manure, and other organic materials. Here are a few examples:

  1. Coffee Grounds: Coffee grounds are a popular alternative mushroom compost that can be collected from local coffee shops or brewed at home. They are rich in nitrogen, which makes them an ideal growing medium for mushrooms.
  2. Cardboard: Cardboard is another alternative mushroom compost that is readily available and can be used to grow certain varieties of mushrooms. It is rich in cellulose, which is broken down by mushroom mycelium to produce food for the mushroom.
  3. Hardwood Sawdust: Hardwood sawdust is an excellent alternative mushroom compost that can be used to grow a variety of mushroom species including shiitake and oyster mushrooms. It is rich in lignin, which provides a good source of nutrition for mushroom mycelium.
  4. Coconut Coir: Coconut coir is a sustainable alternative to traditional mushroom compost, made from the fibrous outer shell of coconut husks. It is rich in nutrients and provides a good growing medium for certain varieties of mushrooms.


How long does mushroom compost last?

Mushroom compost can be reused multiple times for mushroom cultivation if it is properly pasteurized or sterilized between uses. After a mushroom crop is harvested, the spent mushroom substrate can be reused as a soil amendment or added to a compost pile to decompose further.

If stored in a dry and cool place, mushroom compost can last for several months without losing its nutrient value.

Will mushroom compost lower PH?

In general, the pH of mushroom compost is slightly alkaline typically ranging from 7.0 to 8.0. However, the effect of adding mushroom compost to soil on pH levels can vary.

If the underlying soil is already alkaline, adding mushroom compost may raise the pH further. Conversely, if the underlying soil is acidic, adding mushroom compost may help to raise the pH towards a more neutral range.

When should I add mushroom compost to my garden?

Mushroom compost can be added to the garden at any time during the growing season to provide a nutrient boost for plants. It can be used as a top dressing around existing plants or worked into the soil before planting new ones.

Will mushroom compost burn plants?

In general, young or tender plants are more susceptible to salt burn than mature or established plants.

To minimize the risk of burning plants with mushroom compost, it is important to use it in moderation and to avoid applying it directly to plant roots or foliage. Instead, mix the compost into the soil around plants or use it as a top dressing.

What are the plants that do not like mushroom compost?

  1. Acid-Loving Plants: Mushroom compost have a slightly alkaline pH, making it unsuitable for plants that prefer acidic soil. E.g. azaleas, blueberries, and rhododendrons.
  2. Seeds and Seedlings: The high nutrient content and potentially high salt levels in mushroom compost can be too strong for young plants, particularly seedlings.
  3. Native Plants: Some native plants may not do well with mushroom compost, particularly those that are adapted to specific soil conditions or have specific soil requirements.

Can you compost mushrooms?

Yes, mushrooms can be composted along with other organic matter. In fact, composting mushrooms and mushroom waste can be a great way to turn these materials into a nutrient-rich soil amendment that can benefit your garden.

How much mushroom compost per square foot?

In general, it is recommended to apply compost at a rate of 1 to 2 inches deep over the surface of your garden beds or planting areas.

To calculate how much mushroom compost you will need per square foot, you can use the following formula:

The volume of compost needed = (Area of garden bed in square feet) x (Depth of compost in inches)

For example, if you have a garden bed that is 10 feet long and 4 feet wide, and you want to apply mushroom compost to a depth of 2 inches, the calculation would be:

Volume of compost needed = (10 ft x 4 ft) x (2 inches / 12 inches per foot) = 6.7 cubic feet of mushroom compost

What does mushroom compost do to soil?

  1. Increases Soil Organic Matter: Mushroom compost is rich in organic matter which can improve soil structure, texture, and water retention.
  2. Adds Nutrients: Mushroom compost contains a wide range of nutrients including nitrogen, phosphorus, potassium, calcium, and magnesium, which can support plant growth and health.
  3. Enhances Soil Microbial Activity: The organic matter in mushroom compost can help to support beneficial soil microorganisms, which play a key role in nutrient cycling, disease suppression, and plant growth.
  4. Adjusts Soil pH: Depending on the composition of the mushroom compost, it can help to adjust the pH of soil towards a slightly alkaline level, which can be beneficial for some plants.
  5. Suppresses Weeds: Mushroom compost can help to suppress the growth of weeds by smothering weed seeds and providing competition for nutrients and moisture.


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