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Category: Shows and Appearances, Restore The Land, Shows & Appearances
In one month Texas Plant and Soil Lab will be attending the Restore the Land Conference in Bastrop, Texas, this November 6th and 7th. If you plan on attending this two-day event and have not yet secured your lodging, we highly recommend you make reservations now. More information can be found here on the Restore […]
Tue, 06 Oct 2015 12:00:06 +0000

Category: Blog, Acres U.S.A. Magazine, Acres USA 2015
Be sure and check out our ad in the latest issue of Acres U.S.A.® Magazine. And don’t forget! There’s only 10 days left to enter for a chance to win an All-Access Pass to this year’s Acres U.S.A.® Conference including our pre-conference workshop, “Advanced Soil and Crop Health – Maximizing Crop Performance Profitably, Even Under […]
Mon, 05 Oct 2015 12:00:57 +0000

Category: Agricultural Events, Grape Camp, TWGGA
Grape Camp is right around the corner. November 1st and 2nd will be the 2015 Annual Grape Camp at Lady Bird Johnson Park Pavilion, in Fredericksburg Texas. Texas Plant and Soil Lab sponsors Grape Camp annually and will once again this year be sponsoring the Beverage Table and Break Session. Grape Camp is a two-day […]
Fri, 02 Oct 2015 12:42:56 +0000

Category: Agricultural Events, Acres USA 2015, Conference Giveaway
Enter for a chance to win! We’re trying to make going to an Acres U.S.A. Conference even better! With this Conference Giveaway you could win one All-Access pass to this year’s Acres U.S.A. Conference. This all-access pass is a 550 dollar value and includes participation in Texas Plant and Soil Lab’s December 8th all-day workshop. […]
Wed, 30 Sep 2015 14:43:16 +0000

Compost Testing

Order Compost Testing Online
You can now order Compost Testing online. Ordering your compost testing online streamlines the process and provides online order status tracking.

Compost Testing Online Category Page
For the entire Compost Testing Category Page Click Here.

Compost Test Direct Links
To Click Through directly to the Compost Test you wish to order, choose from the list below:

Compost Testing Forms Download Links
To Download and Print forms for ordering Compost Testing, choose from the list below:

U.S. Composting Council

TP&S Lab is the 11th approved US Composting Council Seal of Testing Assurance ( USCC STA ) laboratory for all participating STA composters in the U.S. and Canada! You can find us listed at

Compost Testing and Organic Mix Testing

Composting testing is important for characterizing the beneficial physical and chemical properties of a compost as well as for identifying potential problems with compost use. TP&S Lab employs testing procedures from the U.S. Compost Council’s Test Methods for the Examination of Composting and Composts as well as some proprietary testing methodology that is also essential to measure the quality of your compost.

For example, TP&S Lab measures the humus fraction of the compost as well as the total organic matter to verify that the compost is fully mature. An indicator of compost maturity is high OM (humus) and Nitrate (NO3) > 30 ppm which indicates well matured (cured) compost by biologically active microbes releasing Nitrate (NO3). High OM (humus) and Nitrate (NO3) < 10 ppm indicates a very active to moderately active (curing stage) compost. Adjusting C : N ratio with fertilizer N or biologically with energy (molasses, fish, vegetable meals, etc.) will aid maturity. Just like a conventional fertilizer bag that comes with a guaranteed analysis and a label rate, we must also know the guaranteed analysis of composts to make sure that we apply safe rates to avoid accumulation of excessive mineral salts over time.

See Explanation of Soil Organic Matter here.

General Guidelines of Compost Testing and Organic Mix Testing

pH is a measure of active acidity in the feedstock or compost. Most finished composts will have pH values in the range of 5.0 to 8.5. Ideal pH depends on compost use. A lower pH is preferred for certain ornamental plants while a neutral pH is suitable for most applications. pH is not a measure of the total acidity or alkalinity and cannnot be used to predict the compost effect on soil pH.

Soluble salts are determined by measuring Electrical Conducity (EC) in a 1:5 (compost:water, weight ratio) slurry. Electrical Conducity (EC) is related to the total soluble salts dissolved in the slurry and is measured in units of millimhos/cm (mmho/cm). Composts typically range from 1 to 10 mmhos/cm. High salinity may be toxic to plants. Ideal soluble salt levels will depend on the end use of the compost. Final compost blends with soil or container media/potting mixes should be tested for soluble salts.

The ideal moisture content for composting will depend on the water holding capacity of the materials being composted. In general, high organic matter materials have a high water holding capacity and a higher ideal moisture content. A typical starting compost mix will have an ideal 65-45 % mositure. Finished compost should have a 50-40 % moisture.

Compost Testing Protocols

Review our Online Ordering Page for Compost Testing for a complete list of test descriptions and protocols.

Please contact us today at 956-383-0739 and speak with us
about your needs.

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TP&S Lab is proud to be a member of the Texas Wine and Grape Growers Association.
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