How To Dispose Of Spent Mushroom Substrate Into Fertilizer

Spent mushroom substrate (SMS) is the leftover material from the cultivation of mushrooms. It is primarily composed of a mixture of agricultural by-products such as straw, hay, corn cobs, and other organic materials that have been used as a growth medium for cultivating mushrooms. While spent mushroom substrate may not be as nutrient-rich as the original substrate used for mushroom cultivation, it still contains various organic matter and nutrients. So for spent mushroom substrate management, using as fertilizer is an ideal choice.

Here are some steps you need to take if you’re thinking about using spent mushroom substrate as fertilizer:

Collect and pretreat:

After harvesting your mushrooms, collect the spent mushroom substrate from the growing containers. Then in order to make fertilizer from mushroom waste smoothly, it needs some pretreatment. Such as crushing and drying. And there are professional fertilizer crusher and dryer to help you finish them quickly.


Composting is an effective way to further break down the organic matter in spent mushroom substrate and turn it into a nutrient-rich fertilizer. Mix the spent substrate with other organic materials like animal manure, kitchen scraps, leaves, grass clippings, or straw. Turning mushroom waste compost piles regularly (about once a week) helps aerate the pile, accelerate decomposition, and ensure even distribution of heat. For effective turning of materials, you can use a suitable spent mushroom substrate compost machine.

Maintain Moisture and Airflow:

Keep the compost pile consistently moist, similar to a wrung-out sponge. Adequate moisture encourages microbial activity. Ensure good airflow to prevent the compost from becoming too compacted. Then you can finish the aerobic fermentation of organic waste better.

Monitor Temperature:

The composting process generates heat. Use a compost thermometer to monitor the temperature. A well-managed compost pile should reach temperatures between 130°F to 160°F (54°C to 71°C). This helps kill weed seeds and pathogens.Click here to learn more.


Allow the compost to mature for several weeks to months, depending on factors such as the size of the compost pile, the materials used, and environmental conditions. The compost is ready when it becomes dark, crumbly, and has a rich earthy smell.

Mushroom waste to fertilizer
Mushroom waste to fertilizer

Application to Soil:

Once the compost is fully matured, it can be incorporated into garden soil or used as a top dressing. The compost provides valuable organic matter, improves soil structure, and contributes essential nutrients to support plant growth.

By composting spent mushroom substrate, you can transform it into a valuable and sustainable fertilizer for your garden or crops. The composting process enhances its nutrient content and makes it more beneficial for plant growth. If you are find solution for mushroom waste disposal or composting, you can visit for more details.