Compost, Media, Manure & Humate Testing

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"Essential for rebuilding soil tilth, structure, health and biological activity."

In addition to being an approved laboratory for the U.S. Composting Council, TPS Lab offers its own series of Plant Natural® compost quality tests.


Taking full advantage of compost's potential requires knowledge of its quality. Compost quality is a combination of nutrient content and carbon "decomposability," which is the same as maturity. Maintaining consistent quality makes it much easier to market compost and helps ensure conformance.


TPS Lab can determine your compost's quality accurately and quickly.

  • What is a compost test?

    A compost test is used to evaluate compost quality for use as a soil amendment or as a component of potting mixes.


    Test results are typically used to characterize the beneficial physical and chemical properties and identify potential problems with compost use.


     TPS Lab employs testing procedures from the U.S. Compost Council’s Test Methods for the Examination of Composting and Composts (TMECC) and its own series of Plant Natural® quality tests.

  • Why should compost be tested?

    It is preferable to know the quality of the compost material you plan to use. If nutrients in your compost are released too slowly, the compost won't improve plant growth quickly. On the other hand, if it releases nutrients too quickly, excessive nutrients may be wasted or cause adverse effects.


    Understanding your compost's nutrient levels will help you determine its appropriate use and decrease the amount of fertilizer required. 


    As partially decomposed organic matter, compost can have a range of characteristics. Compost can vary because of the raw materials used, degree of decomposition, moisture content, nutrient content, salt content, acidity/alkalinity, and contaminants (organic and non-organic materials or heavy metals). 


    Some quality measures such as carbon: nitrogen ratio, smell, and particle size indicate some of the above-mentioned characteristics or the composting process's effectiveness. Large particle sizes are indicative of incomplete decomposition. A foul odor is indicative of a too wet or too tight compost pile. Finished compost is dark brown and crumbly and has an earthy smell. The original materials should not be recognizable. Inert materials such as glass or plastic should be no greater than 1 percent of the compost volume. 

  • What information does a compost test provide?

    We offer several options, which may include some or most of the following parameters:


    • Basic Properties: Moisture, pH, Bulk Density, Porosity, Salinity, LOI, Humus, Total Carbon, C: N Ratio, Solvita®  Maturity Index, and Particle Size.


    • Available Nutrients: Texture, Active Organic Matter, Carbonates, pH, Salts, nitrogen (N), potassium (K), phosphorus (P), sodium (Na), calcium (Ca), magnesium (Mg),  zinc (Zn), iron (Fe), copper (Cu) and manganese (Mn).


    • Total Nutrients: Moisture, nitrogen (N), potassium (K), phosphorus (P), sodium (Na), calcium (Ca), magnesium (Mg),  zinc (Zn), iron (Fe), copper (Cu), manganese (Mn), boron (B), cobalt (Co), molybdenum (Mo) and selenium (Se).

    • Fecal & Total Coliform


    • Heavy Metals


    • Maturity: Solvita® & CO2 Evolution 


    • USCC STA & TXDoT

  • What is the STA Certified Compost program and how does it work?

    The US Composting Council’s Seal of Testing Assurance Program (STA) is a compost testing, labeling, and information disclosure program designed to give you the information you need to get the maximum benefit from the use of compost.


    The program was created in 2000 and is the consensus of many leading compost research scientists in the United States. There was no other compost testing program available to compost producers or compost buyers that give you this type of information.


    The science behind the development of the STA Certified Compost Program and the various tests used are contained in "Test Methods for the Examination of Composting & Compost" (TMECC). This publication includes a suite of physical, chemical, and biological tests. 


    These tests were selected to help both compost producer and purchaser to determine if the compost they are considering is suitable for the use that they are planning and helping them compare various compost products using a testing program that can be performed by a group of independent certified labs across the country and in Canada.


    For more information, visit the USCC website, which will provide you with a thorough explanation of all of the "what’s and why’s" of the STA Certified Compost Program and help you get started in enrolling your compost product.

  • Still have questions?

    Ask us your question HERE.