Dig into Mushroom Compost for an Effortless, Thriving Garden

Dig into Mushroom Compost for an Effortless, Thriving Garden

Brandon Rich
Brandon Rich
January 26, 2024
3 min

Mushrooms can have a lot of nutritional benefits to our bodies and minds, and in many cases, to the movement for environmental sustainability. Plus, mushrooms are all sorts of tasty, both palates and for soil conditions. When you consider all that fungi offer, the idea of using mushroom compost in your vegetable garden seems like a no-brainer.

The basics of mushroom compost are less involved than you might expect. However, there are certainly some things you should know about dumping this type of organic matter into your home garden.

What is mushroom compost?

mushroom compost gardening close up

Mushroom compost isn’t actually made from the remains of mushrooms, per se. Instead, this type of compost is created by commercial mushroom growers who turn their spent mushroom substrate into a soil conditioner for your garden plants.

Making mushroom compost

This soil amendment is derived from the used-up substrate of large-scale mushroom-growing operations. According to Epic Gardening, the substrate may include straw, wheat (or other grains), and organic materials like chicken manure, horse manure, and gypsum.

Since every commercial grow is different, you may also find shroom compost with cottonseed hull, canola or soybean meal, corn cobs, or peat moss in the substrate recipe.

These materials are run through several processes of hot composting and sterilization. After going through pasteurization to eliminate weed seeds or undesirable bacteria, mushroom spores are introduced to the substrate. Mycelium forms, and then fruiting bodies grow to become harvested.

Once a mushroom farming operation has gone through the substrate to get the most fruit possible, it is bagged up and shipped out. You may find it labeled as spent mushroom compost (SMC) or spent mushroom substrate (SMS) in your local gardening store.

The pros and cons of mushroom compost benefits

mushroom compost gardening substrate

According to Jack Frost Gardens, mushroom compost is a slow-release fertilizer with long-term usefulness for plant growth. In particular, any garden bed that needs a high level of calcium in the dirt will benefit from a bit of this mix.

Additionally, mushroom compost can be a reliable top-dressing mulch for insulating trees, shrubs, and perennials. Add this mix to your garden well before planting seeds or placing transplants will allow it to mix in with the soil rather than having your plants adjust to the soil by adding it after.

The benefits of using shroom ‘post

You should consider mushroom compost if you have raised beds that need water retention, aeration, and increased soil structure.

As Trees.com reports, mushroom compost can help you conserve water in your garden soil, reducing the amount of moisture you have to give your plants. Over time, this amendment can break down the compact nature of clay soil, providing better overall drainage and allowing more air to permeate.

The drawbacks of mushroom compost

A lot of mushroom composts have a fairly neutral pH level. Yet, if you stumble on a bag with chalk as an ingredient, you may have a mushroom compost that will be too alkaline for your soil, prohibiting essential nutrient uptake for your plants.

Another downside to shroom post’ is the level of soluble salts. Because of this, flowers like azaleas, rhododendrons, and camellias will suffer from high salt levels, as will other salt-sensitive plants like blueberries.

Where to find mushroom-based compost

mushroom compost gardening soil growth

This soil additive is an excellent addition to your garden when used correctly. If you’re looking to diversify your organic fertilizers by using mushroom compost, there are a few ways to do so.

Making compost from mushrooms

If you’ve been in the process of growing mushrooms at home, then you are already half of the way to making mushroom compost. Additionally, this is an excellent place to start if you want to get into home growing.

Horticulture Magazine guides us through a great way to begin the experiment with making mushroom compost. It involves stacking hay, gypsum, and manure in a layered pile, then mixing it all to maintain heat over several weeks.

After the pile has stopped running a temperature, it should be ready to spread. The site recommends that your home-produced substrate be planted with shroom spores or used as-is for compost.

If making mushroom compost seems like a tall task, fear not — you can always just purchase a sack from the store.

Buying mushroom compost

Regarding organic gardening, I personally love the Just Natural Brand, which is sold at a great price and is highly accessible at Lowe’s or Ace Hardware stores. The mix is consistent in texture from bag to bag. Although it is high in salt content and relatively low in remaining nutrients post-mushroom substrate, we’ve found ways to doctor it to our liking.

If you have a pile of regular compost, then you already know the benefits of compost tea, the liquid that drains from the bottom of your tumbler.

Adding this to any bag of commercial (or homemade) mushroom compost will add a host of beneficial microorganisms back into the mix, setting you up for a well-built soil amendment.

The TL;DR of shroom-based compost

mushroom compost gardening soil spade

Overall, mushroom compost can be a really great thing to work into your gardening routine, provided you’re keeping an eye on the plants you’re topping it with.

Though it isn’t wildly nutrient-dense in and of itself, the advantages of this compost on hard-to-manage soil conditions and its slow-release effects make a mushroom compost pile an advantageous placeholder in your garden corner.


Brandon Rich

Brandon Rich

Content Writer

Table Of Contents

What is mushroom compost?
The pros and cons of mushroom compost benefits
Where to find mushroom-based compost
The TL;DR of shroom-based compost

Related Posts

The Best Mushrooms to Start Growing at Home
April 11, 2023
7 min

Our TeamAbout Us