The benefits to the landscaping industry

A handful of mushroom compost.

Ingenious mushroom farmers have begun to recycle their used mushroom soil, which can’t be reused in the growing houses again due to the delicate growing needs of mushrooms, for a totally different market. Many mushroom companies have found that by pasteurizing their spent product, they could sell it to nurseries, landscaping companies, gardening supply centers and the like to use as a soil amendment, mulch and more.

It’s important to know what goes into mushroom soil to grow mushrooms. The American Mushroom Institute (AMI) ( explains that commercial mushrooms are grown in “specially formulated and processed compost made from wheat straw, hay, corn cobs, cotton seed hulls, gypsum and chicken manure. The three to four-week-long composting period is closely supervised and managed to assure that the composting temperatures exceed 160 degrees for a few days in addition to a steam pasteurization, which occurs about one week before mushroom spawn is mixed with the compost. Finally, a layer of sphagnum peat moss, mixed with ground limestone, is topdressed on to the compost and mushrooms grow on the peat.”

Once that soil is used, it’s pasteurized in the mushroom growing house to make spent mushroom substrate (SMS). SMS is considered a negative term in the mushroom growing industry, so the name has changed to “mushroom compost” in the last few years for a more positive connotation of the product. SMS is the material that remains after mushrooms have been harvested and is high in organic matter, making it ideal for use as a soil amendment.

Hy-Tech Mushroom Compost, Inc. was started in 1987 by the Needham family as an arm of their mushroom farming business. Lisa Van Houten, marketing coordinator for Hy-Tech ( in southern Chester County, Pa., says, “Needham Company is one of the largest mushroom growers in Pennsylvania. Through our subsidiary, Hy-Tech Mushroom Compost, we sell pasteurized mushroom soil to a vast array of users from turf management, farming, excavation and landscaping. Mushroom compost is a Pennsylvania Department of Agriculture-accepted fertilizer and a Pennsylvania Preferred product.”

Six Chester County, Pa., mushroom farmers developed Laurel Valley Farms as a co-op to develop their sterilized manure for mushroom growing, as well as a place to recycle their used compost. Glenn Cote, general manager of the compost side of the company, explains that the co-op started in the early 1970s. Laurel Valley Soils is the landscaping arm of the co-op.

Joe Dinorsca, general manager of Laurel Valley Soils (, says the company has been recycling local mushroom farms’ mushroom compost for nine years.

LVS has a compost pad located on 10 acres of their property. LVS utilizes one windrow turner, trammel screens and pay loaders to move the material around to the storage facilities, and there are two buildings for finished materials to dry and stay fresh for customers.

Dinorsca says their biggest seller is the enriched topsoil, which combines mushroom compost and topsoil obtained from construction building sites. It’s a 50-50 mix. “Almost all [of our products] have some mushroom compost, from 15 to 100 percent,” Dinorsca states.

Applying mushroom compost through a blower. Mushroom compost applied to turf as a topdressing.

LVS’ customer base includes landscapers, nurseries and resell-supply companies, who sell the company’s products to professional landscapers.

Hy-Tech delivers mushroom compost throughout the United States. Van Houten says, “If the customer is willing to pay for the shipping, Hy-Tech will deliver anywhere in the U.S. Hy-Tech uses Fastrak Express to deliver to a broad range of industries and users such as farmers, garden centers, excavating, turf, landscaping and residential [customers].”

Both Dinorsca and Van Houten say that educating the landscaping and turf industries to the benefits of using mushroom compost has been their biggest challenge.

Dinorsca advises landscapers to, “One, buy quality materials. Two, require the supply company to use soil testing. We belong to the USCC [U.S. Compost Council], and they have a soil testing assurance program. Certain labs across the U.S. follow their protocol. Penn State University is one of them. [A landscaper] can compare the results of [two soils] and see how they differ.”

An expert weighs in

Peter Landschoot, Ph.D., professor of crop and soil science at Penn State University in State College, Pa., says, “Not all SMS are alike. It depends on how they’re manufactured. Buyer use caution. Find out what goes into them; if they’re pasteurized, how they’re treated after they come out of the production houses. Turf should not be grown in SMS by itself; it should be mixed with soil for best results.”

Landschoot compares mushroom compost against yard compost, and says, “SMS has 40 to 60 percent more organic materials compared with yard waste, that has 20 to 30 percent. One of the positives is that it’s a consistent product. A good company will produce a quality product.”

Landschoot says there are two types of mushroom compost:

• Fresh: The compost is fresh out of the mushroom growing house. The problem with fresh SMS is that it is still able to heat up when stored in piles. Landschoot says, “It’s not fully composted; it’s partially composted. The issue is that it can become physically hot,” which can burn the turf or ground that the landscaper is working on. Landschoot advises to “allow it to cool.”

• Weathered: This compost is stored into piles, called windrows, and is allowed to finish the composting process. “It’s a more common source in the turfgrass industry,” Landschoot explains.

When applying compost to turf, put .25 inch of mushroom compost on existing turf and aerate with a core aerator. “It’s good for places with poor topsoil,” Landschoot says.

For unplanted turf, use 1 to 2 inches of compost layered with 4 to 6 inches of topsoil.

Supply companies

Jimmy Sharpe, owner of Dixie Landscape Supply ( in Columbia, S.C., says a landscape professional needs to try the product on his own first to see the true potential of mushroom compost. “Don’t do a major [job] until you give it a try. Experiment in your own way for a short while, 10 days, to see a difference in the annuals, perennials and vegetables that you planted. Anything that grows fast, see how it’s gained,” he said. Sharpe emphasizes that mushroom compost should be amended into the soil, not applied directly to flower beds or on turf.

In addition to straight mushroom compost, Sharpe also developed Dixie Mix, mushroom compost mixed with other soils to make nursery and turf products. He gets his compost from various mushroom farms in Chester County, Pa.

Sharpe ships his compost as far as Lincoln, Neb. He also has an associate in California who sells mushroom compost to the western section of the U.S.

Steve Lange represents the Black Kow company (, in Oxford, Fla. Black Kow gets their mushroom compost from two large mushroom growers located in north and central Florida, and sells most of their products in the southern half of the U.S. Lange says, “We do sell bulk loads to landscapers by the truckload in Florida and Georgia, but freight costs become more prohibitive over 100 miles from our central Florida location.”

Black Kow doesn’t add any filler to their mushroom compost, but landscapers may as part of their fertilizing process. “Our mushroom compost does not contain any fillers or wood byproducts. It’s a great, nutrient-rich soil amendment to add to sandy soils. Other gardeners and landscapers may include soil conditioners or composted pine bark mulch with our SMS to increase porosity when using it in clay-type soils.”

The author is a freelance writer based in Ephrata, Pa. She writes for various trade magazines focusing on landscape companies, agriculture and business.