Uniform Nomenclature for Quality Soil Products

Since the Mulch and Soil Council was founded in 1972, one of its chief objectives has been to assist the industry and it customers in defining quality products. By maintaining common definitions for quality, the MSC helps the industry assure its customers, and the consuming public, fair competition for bark and soil products and maintains high standards for beneficial product performance and the improvement of man's environment.

This preliminary technical report represents the initial response of the Association to soil product nomenclature in the current market. The use of uniform nomenclature is recommended to individuals, towns and cities, and public and private corporations to specify soil products for use or resale. The advantages of uniform nomenclature for soil products serves both as a product guide and buyer's protection medium.

The MSC sincerely believes widespread adoption of uniform product nomenclature will provide the general public, public agencies, and private corporations with higher quality products while affording buyers a better measure of product comparison and value.

The objectives of the MSC Soil Nomenclature & Labeling Guideline are:

  • To establish industry labeling and nomenclature guidelines for organic soil products by defining those products that are most commonly produced and sold to the lawn & garden and horticulture markets in the United States,
  • To promote uniform and informative labeling of product contents, and
  • To identify for the consuming public those products that provide an acceptable growing medium for plant materials.


COMPOST: Material derived from the biological decomposition of organic matter accomplished by mixing and piling in such a way to promote aerobic and/or anaerobic decay without synthetic fertilizer materials and adjuncts, other than those used to promote decomposition, and which minimizes pathogens, viable weed seeds, and odors.

HUMUS: Material suitable for soil conditioning that is derived primarily from the decomposition of animal or vegetable matter.

MANURE: Dried, pulverized, shredded, composted, or otherwise processed, manipulated, or treated animal manures are the excreta of animals together with whatever organic bedding or other materials are needed to follow good dairy barn, feedlot, poultry house, etc., practice in order to maintain proper sanitary conditions, to conserve plant food elements in the excreta, and to absorb the liquid portion without the addition of other material.

PEAT: Naturally occurring material suitable for soil conditioning and formed chiefly from the decomposition of organic matter in a water-saturated environment.

PEAT MOSS: Naturally occurring material formed chiefly from the partial decomposition of moss plants and organic matter in a water-saturated environment.

PLANTING MIX: A mixed or blended material suitable for holding and growing indoor and/or outdoor plants, and made primarily from natural soils, peat, humus, compost, and/or manure. It may include fertilizer, pesticides, and/or additives intended as soil conditioners (e.g., perlite, vermiculite, sand, peat moss, charcoal).

POTTING SOIL: Material suitable for holding and growing potted plants and made primarily from natural materials, such as bark, peat, humus, compost, and/or manure. It may include fertilizers, pesticides, and/or additives intended as soil conditioners (e.g., perlite, vermiculite, sand, peat moss, charcoal).

PRODUCT LABEL: An information panel which shall be prominently displayed on the product bag and which shall list the contents of the bag by component materials in declining order by percentage of volume.

PRODUCT NAME: The primary identification of a product given by the manufacturer and printed most prominently on the front of a product bag for the purpose of identifying the product to the consumer.

PROFESSIONAL POTTING SOIL: Material suitable for holding and growing potted plants and made primarily from bark, peat moss, peat, humus, compost, and/or manure. It may include fertilizer, pesticides, and/or additives intended as soil conditioners (e.g., perlite, vermiculite, sand, charcoal). It is a blended product which has a high percentage of sphagnum, vermiculite, bark and other lightweight materials with a high porosity.

SLUDGE / BIOSOLIDS: The solid precipitate, resulting from water or sewage treatment processes, that contains human waste matter.

TOP SOIL: Material suitable for growing outdoor plants, such as grass and shrubs, generally high in organic matter and made chiefly from natural materials, such as soils, peat, humus, compost, and/or manure.

A Voluntary Industry Guideline of the MSC

Soil Characteristics

In order to provide a neutral growing medium capable of delivering existing or added nutrients to plant materials, soil products are generally formulated to fall within the pH and soluble salt ranges shown in the following table. However, these numerical limits do not tell the entire story on the quality of any mix and some products can fall outside the recommended ranges while still delivering an excellent growing result due to complex interactions with other ingredients in the mix.

All certified soil products must pass a required series of greenhouse growth tests to earn the right to display the MSC Certification Mark on their bags.

Product pH Range* Soluble Salts*
(in millimhos/cm)
Compost 4.5 - 8.0 0 - 20.0
Humus 3.5 - 7.5 0 - 5.5
Manure 4.5 - 9.0 0 - 100.0
Peat 4.5 - 7.2 0 - 3.5
Peat Moss 3.0 - 6.5 0 - 3.5
Planting Mix 4.5 - 7.5 0 - 7.0
Potting Soil 4.5 - 7.5 0 - 5.5
Professional Mix 4.5 - 7.5 0 - 5.5
Sludge 4.5 - 7.5 0 - 20.0
Top Soil 4.5 - 8.0 0 - 20.0

*Saturated Paste Extract Method

Soil Labeling Requirements

In order to qualify for the licensing of the MSC product certification logo mark, each licensee must agree to comply with the following soil product labeling guidelines:

  • 1. Product names, soil characteristics, and label terminology must conform to the product definitions of this guideline.
  • 2. Product names that incorporate or refer to a single specific material must be comprised of 100% of that material.
  • 3. Product names that list a specific material as "first-mentioned" among other materials must be comprised of more than 50% of that product by volume.
  • 4. Product names that list a component material or materials on other than a first-mentioned basis must be comprised of at least 10% of the named material(s) by volume and such materials shall be listed in the name in the declining order of their volume content.
  • 5. Product names which indicate a specific animal manure by name, picture, graphic, drawing, or other means (i.e., cow, sheep, poultry, etc.) shall contain more than 50% of that specific animal manure as part of its total manure content by volume.
  • 6. A product label shall appear on each product bag. Product labels shall list the component materials of a product in declining order by percent of volume, except that all materials that are less than 2% of total product volume, individually, shall be grouped together under the category "other trace materials", and the specific percentage of product volume of each listed material need not be given on the product label.
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