Quality you can trust
The US Composting Council (USCC) Seal of Testing Assurance (STA) Program is a national compost testing program that lets buyers take a peek ‘under the hood’ so to speak, before buying.
Standards, facts and transparency. That is what you get when purchasing STA Certified Compost. Think of the STA like you would a Carfax report but for compost. You wouldn’t buy a car without all the facts—and we wouldn’t suggest you purchase compost without the facts either.

STA Certified Compost
Quality is in the eye of the consumer. Compost use and selection decisions consider many factors, and therefore are not one-size-fits-all. The Seal of Testing Assurance(STA) Program helps you make the best decision for your application by providing the 3 C’s:

Clarity
Similar to a nutrition label, the STA Program’s Compost Technical Data Sheet (CTDS) includes test results, a list of ingredients, and recommended directions for use.
Consistency
The STA Program provides checks and balances within the STA Lab and Participant network to ensure proficiency and consistency with testing procedures and compliance, providing apples to apples comparisons of compost properties.
Confidence
Similar to trusting a vehicle history report when purchasing a vehicle, the STA’s CTDS report provides consumers with confidence and knowledge of what is in the compost and how it was produced.
How does the Seal of Testing Assurance Program (STA) work?
The USCC’s national STA program provides a network of approved laboratories which strictly follow the comprehensive guidelines for Test Methods for the Examination of Composting and Compost (TMECC). TMECC sets standards for the suite of specific tests required as well as how the testing procedures are run, right down to how the instrumentation is calibrated. This ensures testing uniformity throughout all the labs in the program across the country.
Composters pay an annual fee to participate in this program which then requires them to submit their compost for testing several times a year, more or less often depending on the volume of compost their particular facility produces.
Participating labs conduct the STA testing and provide the participating composters with Compost Technical Data Sheets (CTDS). The beauty of this program is that it gives the consumer a way to do an apples to apples comparison between the different STA Certified compost producers in their area.
This means that all the test results, including pH, organic matter, soluble salts etc., can be evaluated equally side by side. This is the only accurate way to compare the data from two or more composts. This empowers the consumer so they can make the most educated decision when choosing a compost to purchase.
Simply put, if it’s not STA, then what is it?