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Compost Classification and Specifications

Compost is not soil and soil is not compost. When evaluating true compost products, the fact that there are several types of compost products available must be considered. The type of use desired, methods of application and incorporation available, soil characteristics at the application site, and site topography must all be considered to select the most beneficial class of compost.

Class I Compost

Requirements to meet Class I Standards

ANALYTICAL

Minimum Stability Indicator (Respirometry)

The product should obtain a rating of stable to very stable.

Soluble Salts

Maximum of 5 mmhos/cm.

pH

6.0 – 8.0

Ag Index

> 10

Maturity Indicators

Percentage of Germination and Vigor – 80% or more for both Germination and Vigor.

Ammonia N / Nitrate N Ratio - < 4

Carbon to Nitrogen Ration - < 12

Tested for Clopyralid

The product should be tested for Clopyralid and the test should indicate that it is not present and will not pose a threat to plant germination and health.

Bulk Density

Reported on submittal documentation.

% Inorganics

Reported on submittal documentation.

Moisture

Reported on submittal documentation.

Particle Size Distribution

Indicate specific requirements, or reported on submittal documentation.

Primary Nutrients

Reported on submittal documentation.

Secondary Nutrients

Reported on submittal documentation.

Trace Elements

Reported on submittal documentation.

Format of Analytical Data

As presented by the Seal of Testing Assurance requirements or equal, utilizing TMECC methods.

Organic Matter per Cubic Yard

Reported on submittal documentation, but no less than 200 pounds per cubic yard.

Chemical Contaminants

The submittal documents should show that the product meets or exceeds the US EPA Class A standard, 40 CFR 503.13 tables 1 & 3 levels.

Pathogens

The submittal documents should show that the product meets or exceeds the US EPA Class A standard 40 CFR 503.32(a) standards.

 

MANUFACTURING

Minimum Manufacturing / Production Requirement

The manufacturer of the product should meet a level 1 requirement

 

APPLICATION / RISK

Applications

Horticultural, Nursery, Container Mixes, Turf, Sod, Seed Bed Preparation, Raised Garden, Vegetable Gardens, Top Soil Blends, Backfill, Erosion Control. Watering to leach excess salts not required. Can be applied at high volume. Incorporation can be at shallower depths.

Risk Factor Relating to Plant Germination and Health

Low

Incorporation Notes

Can be used as a high percentage of the soil profile. Incorporation not critical (top 4" recommended).