How to Make Your Own Mushroom Compost as a Recycling Method

There are many types of composting that you can try setting up in your backyard. We’ve already talked about worm composting and how to make a composting bin. Now, it’s time to take things to another level and see what mushroom compost is all about.

What Is Mushroom Compost?

Humans have come up with different green practices in our attempts to leave a smaller carbon footprint on our environment. Mushroom compost is one of the best additions you can make to you garden soil. There are several ways you can try organic gardening with mushroom compost, and each one of them offers specific benefits to the garden.

Mushroom compost is an organic plant fertilizer that slowly releases into the garden soil. The compost is made by mushroom growers with organic materials they already have, including straw, hay, corn cobs and hulls. Poultry and horse manure can also be added, but not cat or dog poop, because of the bacteria.

Individual growers will have different mushroom growing processes, which means that the mushroom compost recipes often vary. For example, you can also add materials like lime, gypsum, soybean meal, peat moss, and other organic items into the compost.

Mushroom Compost: How to

Once you mix the ingredients together, the huge piles of mushroom compost must sit for about 30 days to do what compost does – gradually heat up. The bacteria feeds on the straw, cottonseed meal and chicken manure, which provide most of the required nutrients.

In order for the mushrooms to grow, a mixed layer of lime and sphagnum moss is added at the top of the pile. Weed seeds and other harmful pathogens that might have been present in the animal wastes and in the straw have no chance of surviving as the bacteria multiply. They cannot stand the high temperature inside the pile, which can go as high as 170 degrees F.

During the processing weeks, mushroom compost is closely monitored by mushroom growers, who make sure that the pile maintains adequate temperatures. The resulting mushroom compost is ready to be used in growing a crop of commercial mushrooms. After one composting cycle is complete, the leftover compost can also be sold as fertilizer to gardeners, landscape supply firms, nurseries, and general contractors.

Mushroom Compost as a Recycling Method

Mushroom farms use available agricultural materials to form the nutritious substrate for mushroom production. This recycling process is essential to a proper mushroom production. Check out the infographic below for more information.

Mushroom Compost and Roadside Vegetation

When it comes to establishing roadside vegetation, the best way to approach mushroom composting is by applying it uniformly in layers of 1-3 inch thick. Once the intended site is covered, wait for the compost to incorporate into the existing soil.

Next, plant the seeds of the desired vegetation – or simply transplant it into the new soil. Be aware that sites with steep slopes may need netting or erosion blankets to prevent the possibility of soil erosion.

Mushroom Compost Benefits

In spite of some downsides (see the section below), there are many beneficial uses of mushroom compost. If you need some motivation to establish your own production, check the list below.

  • Mushroom compost is rather inexpensive, much like any other type of composting.
  • It’s not only cheap to get started, but it also enriches the soil, offers nutrients and helps grow healthy plants.
  • Mushroom compost improves the soil’s water-holding ability, which will significantly decrease your garden’s watering needs.
  • Most garden plants benefit from mushroom compost added into their soil, including fruits, vegetables, herbs and flowers.
  • To get the best results when getting started on organic gardening with mushroom compost, make sure the compost is thoroughly mixed in with the garden soil. If possible, allow it to sit over winter and start your garden next spring.
composted soil


Downsides of Mushroom Composting


Mushroom compost should be used with caution in some situations when the high soluble salt levels can damage the plants. In these cases, adding mushroom compost can kill germinating seeds and cause damage to young seedlings and salt-sensitive plants (rhododendrons and azaleas included).

Turfgrass and other groundcover-type plants are also harmed by excessive amounts of soluble salts – such as magnesium, calcium, and potassium. However, according to research at Penn State, good quality mushroom compost does not cause damage to turfgrass seed germination. The soluble salt concentrations are not high enough for that.

Also, if the compost is thoroughly incorporated into the soil, that dilutes the salt concentration greatly. Natural rainfall and irrigation can also further reduce salt concentrations. If you buy the compost instead of making it, make sure your get a good quality and reliable product.


Mushroom compost is pasteurized (steam-treated) before it is removed from a mushroom production house. This process eliminates any pathogens, pests, and weed seeds that might infest the finished product.

However, not all mushroom compost is created equal. Garden centers sometimes sell “mushroom soil,” which has simply been sitting outside in a pile for some months or even years.  Leaving it unattended causes the soil to accumulate air-borne weed seeds.

Once this compost is incorporated into a garden, those weed seeds come in strong, ruining your efforts. We cannot stress this enough: Make sure you buy uniform and quality compost. That means the final product is the result of pasteurization, processing, and properly storage. This is the only way to prevent contamination from weed seeds.

Composted Soil for Gardening

You can buy mushroom compost in bags of spent mushroom compost (SMC) or spent mushroom substrate (SMS). Many garden centers and landscape supply companies carry the product. Depending on how much you need, you can either start your own production of mushroom composting or purchase it by the truckload or bushel.

Wrapping It Up

More than anything else, mushroom composting requires determination and a strong will. You will need them as you patiently wait for the bacteria to do their job. However, if you start your own production, you will soon feel the satisfaction of being able to recycle items that would otherwise end up in the local landfill.

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William E. Eubanks

I'm one of the main writers on the site; mostly dealing with environmental news and ways to live green. My goal is to educate others about this great planet, and the ways we can help to protect it.

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