Spent mushroom compost is the soil-like material left after growing a crop of mushrooms. It is high in organic matter, making it desirable for soil amendment or conditioner use.
Compost, prepared specifically for growing mushrooms, is a blend of natural products. Common ingredients are wheat straw, alfalfa straw, poultry manure, cottonseed meal, alfalfa seed screenings, cottonseed hulls, and gypsum. Later in the process, grain and protein are added, and before harvesting, the 8-inch layer of compost is covered with a 2-inch layer of peat moss and lime.
During the composting process, water is added, and temperatures often rise to about 170 degrees. After the compost is made, it is pasteurized at 140 degrees, and later, after all mushrooms have been harvested, it is sterilized at 160 degrees for several hours. Spent mushroom compost will be free of weed seeds and insects.
Spent mushroom compost will vary depending on how long it has been stored in our field. It is also important to know what type of soil you are applying it to.
There are many uses for mushroom compost. Spent mushroom compost is excellent to spread on top of newly seeded lawns. Since some plants and garden vegetables are sensitive to high salt content in soils, avoid using fresh compost around those plants. You may use spent compost weathered for six months or longer in all gardens and with most plants. Obtaining mushroom compost in the fall and winter, allowing it to weather, will make it ready to use in a garden the following spring. Spring and summer are the best time to use weathered material as a mulch.
Superior Water Retention: Our compost pellets are designed to hold moisture, keeping your plants hydrated longer, even during dry spells. This means less watering for you and more consistent growth for your plants.
Rich in Humates: Packed with humic acids, our compost pellets enhance soil fertility and stimulate plant growth. Humates improve nutrient uptake and soil structure, leading to healthier, more resilient plants.
Easy Application: Whether you’re tending to gardens, lawns, flowers, or trees, our pellets are perfectly sized for use with a rotary spreader. This ensures even coverage and a hassle-free application process.
Greener Grass and Higher Yields: Enjoy lush, green lawns and more productive gardens with our mushroom compost pellets. Enriching the soil with essential micronutrients and humates will make your grass greener, and your plants will yield more bountiful harvests.
Reduces Fertilizer Needs: Reduce the chemical fertilizers required for your garden. Humates release nutrients tied up in the soil after years of applying synthetic fertilizers.
Essential Micronutrients: Our pellets are an excellent source of copper and iron, vital for plant health. These micronutrients are crucial in various plant functions, including chlorophyll production and disease resistance.
Since we don’t have truck scales, we cannot guarantee tonnage. We will do our best to load as full as we can.
This is loaded at our facility. You must present yourself to our front office for payment and a receipt Monday through Friday, 8:00 a.m. to 2:00 p.m., except on holidays.
Spent mushroom compost also known as mushroom soil, mushroom compost, or SMS is an excellent soil amendment for gardens. As a passionate gardener myself, I highly recommend using spent mushroom compost in your vegetable and flower beds. In this comprehensive guide, I’ll explain everything you need to know about mushroom compost and where to buy it.
What is Spent Mushroom Compost?
Spent mushroom compost is a byproduct of the mushroom farming industry. It’s made from a mixture of straw, chicken manure, gypsum, and other ingredients used to grow mushrooms commercially
Once the mushrooms have been harvested this nutrient-rich material is pasteurized and sold as an organic soil amendment. Spent mushroom compost has a rich, earthy smell and appearance similar to high-quality potting soil.
Benefits of Using Spent Mushroom Compost
There are many benefits to using spent mushroom compost in your garden:
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Increases soil organic matter – Mushroom compost contains partially decomposed organic materials that improve soil structure and water retention.
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Provides nutrients – It contains nitrogen, phosphorus, potassium and other minerals that plants need to grow. Mushroom compost acts as a slow-release fertilizer.
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Improves drainage – The lightweight texture helps aerate heavy clay soils and improve drainage.
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Increases moisture retention – The organic matter acts like a sponge to hold water in sandy soils.
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Promotes healthy soil microbes – The diversity of organic materials feeds beneficial soil organisms like bacteria, fungi, and earthworms.
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Adjusts pH levels – Mushroom compost is usually mildly acidic, which brings pH into the optimal range for nutrient availability.
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Suppresses plant diseases – The pasteurization process kills pathogens and weed seeds.
How to Use Spent Mushroom Compost in Your Garden
Spent mushroom compost can be added to garden beds before planting or used as a mulch around existing plants. Here are some tips:
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Till 2-3 inches of compost into vegetable and flower garden beds before planting.
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Spread 1-2 inches around trees, shrubs, and perennials as a nutritious top dressing.
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Mix 25-50% spent mushroom compost into potting soil for containers and raised beds.
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Add a 1-2 inch layer around plants and work lightly into the top 1-2 inches of soil.
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For new gardens, apply up to 75% mushroom compost mixed with 25% existing native soil.
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Use spent mushroom compost to top dress lawns, golf courses, and playing fields.
Mushroom compost is loose and fluffy when first applied but will settle over time. Reapply yearly or as needed to boost nutrients and organic matter. Be sure to water thoroughly after application to help integrate it into the soil.
Where to Buy Spent Mushroom Compost
Now that you know the benefits of mushroom compost, let’s discuss where you can buy it. Here are some options:
Local Mushroom Farms
I recommend checking for mushroom farms in your state or region. Many offer spent compost directly to consumers at wholesale prices. You’ll save on delivery fees by picking it up yourself. Typical pricing ranges from $10-20 per cubic yard. Here are some mushroom farms that sell compost:
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Kitchen Pride Mushroom Farms in Texas sells compost for pickup by appointment.
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Mushroom Mountain in South Carolina sells compost along with mushroom grow kits.
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Monterey Mushrooms has compost available at their facilities in California, Tennessee, and Pennsylvania.
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Country Fresh Mushroom Co. offers pickup in Indiana. Call ahead as supply fluctuates seasonally.
Landscape Supplies or Nurseries
Many landscape materials suppliers and nurseries stock mushroom compost either bagged or in bulk. The selection varies by region. Expect to pay more than direct from a mushroom farm but you may find it more convenient.
Online Suppliers
You can order spent mushroom compost online from various suppliers that will ship it directly to your door. Some popular options include:
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American Mushroom Institute – Network of mushroom farms across the US. Enter your zip code to find a compost provider near you.
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Compost Direct – Sells and ships bulk mushroom compost nationwide.
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Nature’s Footprint – Offers bagged pasteurized mushroom compost for garden use.
Check shipping costs carefully as they can be high for bulk quantities. Make sure to compare costs vs sourcing locally.
How Much Spent Mushroom Compost Do You Need?
Most mushroom compost suppliers sell by the cubic yard, which is 3 feet x 3 feet x 3 feet, or 27 cubic feet. Here are some guidelines for how much you’ll need:
- 1-2 cubic yards per 1000 sq ft for establishing a new garden
- 1 cubic yard covers about 75-100 sq ft at a 2-3 inch depth
- 5-10 cubic yards to amend soil when planting trees, shrubs, and perennials
- 1-3 cubic yards for top dressing lawns and establishing turf
If working with bagged compost, here are some equivalents:
- 1 cubic yard = 27 cubic feet = about 9-10 typical 1 cubic foot bags
- 1 cubic foot bag covers 8-12 square feet at a 1-2 inch depth
For large projects, consider ordering compost by the truckload, which is about 20-30 cubic yards. Mushroom farm pickups often require a minimum order of 1-3 yards.
Spent Mushroom Compost Recap
Spreadable Pellets
Beginning January 2024, we are rolling out Spreadable Compost Pellets. We will sell the pellets in 25-pound (1/2 cubic foot) and 50-pound (1 cubic foot) bags. The pellets are made so that you can enjoy the benefits of mushroom compost on your lawn, garden, flowers, and trees using a common fertilizer spreader.
Click here for a lab analysis of the pellets. The NPK for this sample was 2-1.7-2.1.
Is Mushroom Compost Good For A Garden Or Should You Avoid It?
FAQ
Is spent mushroom compost good?
With a pH scale of around 6.6, Spent mushroom compost is great for many things, including improved soil structure, weed reduction and moisture retention.
How much is 1 yard of mushroom compost?
Mushroom Compost – $43.00 Per Cubic Yard. Delivery calculated at checkout. Buy online and schedule your delivery at checkout. We offer delivery within a 30 mile radius for our Mushroom Compost.
What are the downsides of mushroom compost?
Frequent or heavy use of spent mushroom compost usually leads to a build-up of chalk particles in the garden soil, and to increased soil alkalinity. This can occur to the extent that plant growth suffers, the chalk making other nutrients in the soil less available.
When should you not use mushroom compost?
Mushroom compost should be used with caution due to its high soluble salt levels and alkalinity. These salt levels can kill germinating seeds, harm young seedlings, and cause damage to salt-sensitive plants, like azaleas and rhododendrons. To temper the alkaline levels of mushroom compost, consider using aglime.