What is Mushroom Compost? How to Use It

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Mushroom compost has been used for centuries to improve soil fertility and increase crop yields. 

Today, mushroom compost is used in gardening and landscaping, and it is often added to home gardens and backyards to improve their overall health and appearance.

Mushroom compost isn’t actually the traditional compost that we know. It’s not compost made of decomposed mushrooms either, nor is it compost used to grow mushrooms in. 

Learn all about mushroom compost and plants that don’t like it in this article. 

What is Mushroom Compost?

Mushroom Compost is also known as Spent Mushroom Substrate, because it’s the remaining substrate after mushrooms have been harvested from a mushroom farm. 

The remaining mixture of mushroom spawn, straw, sawdust, and other organic materials that was used to grow mushrooms is known as mushroom compost. It’s all this organic matter and the mushrooms where the nutrient content comes from.

The main purpose of using mushroom compost is to improve moisture retention and provide nutrients for gardens. It’s used as a soil conditioner and mulch for lawns, vegetables gardens, and to improve soil quality. 

There are also a variety of mushroom compost types available on the market today. There are a couple main types of mushroom compost: Fresh and Aged. 

Fresh mushroom compost is usually sold at local garden centers or nurseries because they’re fresh. This type of mushroom compost will be very moist when purchased. The bag should contain enough material so that you won’t need to add water once you start adding your own spent mushroom substrates. 

Aged mushroom compost is like fresh compost, but it goes through an extra decomposition process. After being aged, the mushroom compost becomes more stable and less prone to mold growth. It is typically dry and crumbly. 

The mushroom compost will all have gone through a pasteurization process which kills any harmful microorganisms, bacteria, and weed seeds present in the original mix. 

The bags of mushroom compost you find online and in most large grocery stores are usually aged. These bags can last up to two years if stored properly. They’ll keep longer than fresh mushroom compost. 

Here’s a popular aged mushroom compost option online:

Is Mushroom Compost Good for a Vegetable Garden?

Yes, mushroom compost is good for a vegetable garden. It’s a great way to improve soil quality and retain moisture. Mushroom compost will also add many nutrients to your soil. 

However, do be careful with using too much of it. It is very good at soaking and retaining water, so you could end up with soggy soil that can kill your plants. Never use more than 50% in your garden. 

It’s important to note that mushroom compost is not the same thing as compost. Compost is created by mixing together various plant waste products such as leaves, grass clippings, and wood chips. 

How to Use Mushroom Compost?

There are many ways to use mushroom compost.

You can add it directly into your garden or landscape beds. Or you can spread it on top of existing grassy areas such as flowerbeds, vegetable gardens, and even around trees and shrubs. 

If you’re looking to make some improvements to your yard, then adding mushroom compost will help with drainage issues, weed control, and plant growth. 

You may want to mix some with peat moss before spreading it out over your yard. This will help keep down weeds and prevent erosion. 

If you’re growing flowers, adding mushroom compost helps them stay healthy by improving water absorption and retaining more moisture. 

When adding it to help plant growth, be careful with plant root burns. To prevent burning out plant roots, add the mushroom compost close to the stems and roots for easy nutrient absorption. 

On lawns, mushroom compost improves turf growth and reduces weed problems. If you’ve got an area where there aren’t any trees or bushes nearby, then you could plant something new right next to your house. 

You also won’t need to add any extra fertilizer to your lawn for that growing season because there are plenty of nutrients in the mushroom compost. 

pH Levels and Nutrient Composition in Mushroom Compost

Mushroom compost usually has pH levels ranging between 5-7 depending on what kind of substrate you choose. You can buy mushroom compost with specific pH levels, which makes it easier to know exactly how much acidity or alkalinity each batch contains. 

Most commercial mushroom compost products have a pH level of around 6.5 for a neutral pH level. However, you don’t always need to worry about having too high or low pH levels.

There are plants that prefer higher pH levels, while others do better with more acidic soil

Do note that mushroom compost will differ depending on the brands and mushroom farms that you purchased from. 

Mushroom compost also has a high amount of soluble salts, so it shouldn’t be used when trying to germinate seeds. The salt levels will prevent seeds from growing and young seedlings from growing. 

The nutrients available will depend on what garden soil and soil ingredients were originally used for the mushroom substrate. 

Many popular mushroom compost recipes will include: chicken manure, soybean meal, corn cobs, bales of straw, coffee grounds, bales of wheat straw, horse manure, and other popular compost ingredients.

Then, if it’s aged mushroom compost, were there additional ingredients added to the compost pile for further decomposition from the fresh mushroom compost. That would provide another source of nutrients.

Be careful of companies or farms that use any chemicals with their fertilizer and pesticides. There may be chemical residues in the mushroom compost, even after pasteurization and sterilization. 

Plants That Don’t like Mushroom Compost

Mushroom compost has a neutral pH level, so it’s not good to add this to plants who like acidic soil and lower pH content, or higher alkaline content. With its water retention ability, plants that need well-draining soil will not like it.

There are also plants that don’t like salt content, so avoid adding mushroom compost for those plants. 

Plants that won’t like mushroom compost include: 

  • Azaleas
  • Blueberries
  • Camellias
  • Cranberries
  • Gardenias
  • Heathers
  • Hydrangeas
  • Magnolias
  • Rhododendrons
  • Viburnums

Plants That Like Mushroom Compost

Most types of plants will like mushroom compost as it has a neutral pH level and has good water retention. 

Generally, mushroom compost will be beneficial for: 

  • Flowers
  • Fruits
  • Herbs
  • Lawns
  • Shrubs
  • Trees
  • Vegetables – For example, Artichoke, asparagus, beet, broccoli, cabbage, caluiflower, celery, lettuce, onion, and spinach. 

Alternative to Mushroom Compost 

The main alternative to mushroom compost is traditional compost.

Traditional compost has gone through the composting process of decomposition. The process breaks down organic materials into nutrients for plant growth.

Composting involves using organic materials such as leaves, grass clippings, kitchen scraps, paper, cardboard, wood chips, sawdust, etc., to create nutrient-rich material that helps improve the health of your soil. 

Mushroom Compost Final Thoughts

Mushroom compost is an excellent way to enrich your soil. It provides many benefits, including improving water retention, drainage, increasing fertility, and helping plants grow faster. 

However, make sure to use only quality mushroom compost made by reputable companies. 

Other related articles to learn more: 

Mushroom Compost FAQs

Can you use mushroom compost on all plants?

You can use mushroom compost on most types of plants, from herbs to vegetables. However, there are certain plants that do not like mushrooms. Some plants that like acidic or alkaline soil will not have an advantage from mushroom compost, because it has a neutral pH level. Therefore, it is best to apply mushroom compost only to soil that doesn’t need to have its pH adjusted.

Can mushroom compost burn plants?

Yes, mushroom compost can burn plants. However, it is important to use only organic compost, which contains no pesticides or herbicides. The chemicals from the mushroom compost could lead to plant burns. 

Is mushroom compost better than cow manure?

Mushroom compost is better than fresh cow manure because it does not contain pathogens. Cow manure can cause diseases if applied directly to the roots of plants. Also, mushroom compost is easier to work with when applied to gardens. You just spread it out over the area where you want to put it. If you want to use cow manure, it’s best to compost it first, where compost heat will kill off the pathogens. 

What is the best compost for a garden?

The best compost for a garden is aged compost. It will smell earthy, feel crumbly and have a rich, dark brown color. You shouldn’t recognize any of the original compost ingredients in the finished compost. You’ll be able to achieve this with a 50/50 balance of brown and green compost materials.

Do roses like mushroom compost?

Yes, rose bushes love mushroom compost, but the compost should be made from a mixture of different types of organic matter such as manure, straw, sawdust, leaves, and wood chips. Add the mushroom compost at the bottom of the pot or soil hole, acting as a fertilizer.

What vegetables like mushroom compost?

Vegetables that like mushroom compost are ones that will grow well in neutral soil, pH level of 6.5 to 7.5. This includes vegetables like artichoke, asparagus, beet, broccoli, cabbage, caluiflower, celery, lettuce, onion, and spinach. 

Do worms like mushroom compost?

Worms love mushroom compost! Worms like how mushroom compost retains moisture for vermicomposting. They eat the mushroom compost and turn it into worm castings which is used for fertilizing plants. Worms also help decompose organic matter and break down waste.

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Written by:

Denise Davis
Denise Davis is an avid gardener, deeply rooted in growing organic veggies and crafting homemade fertilizers. She cherishes the earthy essence of composting and the continuous learning that gardening provides. Denise sees gardening as a holistic activity, offering physical and mental benefits alongside the joy of consuming what you cultivate. Her passion is to inspire others to embrace gardening as a rewarding, healthful lifestyle.

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