Mushrooms & Compost

July 6, 2018

By: Ron Kushner

Mushrooms in the landscape

Mushrooms are the fruiting bodies formed from fungi. The purpose of the mushroom is to release sexual reproductive spores. All mushrooms have a cap and gills. The cap protects the reproductive surface (the gills) until it pushes up through the ground. Then the cap expands and the spores are released from the gills which the wind carries to find a suitable substrate for them to grow in.

Mushrooms may or may not have a stem. They are not really classified as “plants” but are part of the family “fungi”.

Most fungi are composed of thread-like filaments called “hyphae” and ultimately form a mass or “body” called a mycelium. They live in the soil, taking in nutrients as they help break down the decomposing soil. Their biggest ecological function is their interaction with plants to form mycorrhizae. Mycorrhizae result from the fungi connecting with the root cells of plants. The fungus provides nutrients to the plants (especially phosphorus) and the plant provides the fungus with carbon that it converts into sugar compounds.

Be careful! Most mushrooms are not edible and many are actually poisonous. Some will kill you and others will make you very sick. Make sure that you know what you are doing if you harvest mushrooms in the wild. Get expert verification of the identity of the mushroom.

Mushrooms do not have roots, leaves, flowers or seeds. They have no chlorophyll so they need to interact with plants to create sugar that plants manufacture by taking in water, carbon dioxide and sunlight. The fruiting body is really not the whole mushroom, just the reproductive part.

Each mushroom spore is a single cell.

Mushrooms originated in Egypt with the Pharoahs, according to history, then Russia, Greece and all over. Paris, France was the first recorded actual cultivation, then England and finally the United States.

Mushrooms sprout up in our lawns, especially after wet weather. They could be growing in circles of dark, green grass. When the weather gets colder or the soil dries out, they tend to disappear. They live on organic matter buried in the soil such as buried logs, lumber, old tree roots or stumps. They are unsightly but they rarely do damage to your lawn. There is no practical way to eliminate them. When the buried wood matter is totally decayed the mushrooms will be gone. All you can do is rake them up or mow them down. There are no chemical solutions.

Commercial mushrooms and mushroom compost

Pennsylvania is the top producer of edible mushrooms in the country. 65% of every mushroom in the United States comes from PA. Laurel Valley Farms in Avondale, PA creates the mushroom compost for the mushroom farmers to grow edible mushrooms.

Since mushrooms have no ability to make their own food, compost is needed. Laurel Valley Farms buys 40,000 tons of hay and 25,000 tons of straw every year.

These ingredients are broken down and watered for three weeks. They are then blended with poultry manure, corn cobs and horse manure and bedding. These additives provide bacteria and other micro organisms to further break down the material. This process creates the carbon which becomes an important food source for the mushrooms. It is combined until the temperature becomes 160 degrees F.

It is then transported and loaded into small, dark buildings called “doubles”. It is loaded into growing beds and treated with spores. The mushrooms grow in “flushes” and about 60,000 pounds a day are harvested. After three flushes, it is no longer economical to use the same compost for a future crop, due tot he reduced carbon levels.

However, this compost still has lots of valuable nutrients for growing beautiful, healthy plants. It is further composted for about 6-9 months (as the mushrooms prefer it be only partially composted) and recycled for use in urban gardening initiatives, farming applications, nurseries, golf courses, by landscapers, sold by garden centers and used in green roofs. It is turned into a high-grade soil and the process has been going on since the early 1900’s.

Every week, Laurel Valley Farms recycles:

  • 450,000 gallons of storm water
  • 75 tons of corn cobs
  • 7,000 cubic yards of horse bedding
  • 40 tons of cocoa shells
  • 600 tons of poultry manure

A total of 7,000 yards of mushroom compost is recycled every week. That is enough to cover 157 football fields with 1/4″ of compost!

Thanks to Laurel Valley Soils for providing much of the information for this article.

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