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On large jobs or projects in sensitive areas, it is a good idea to test the seed you receive. Problems can legitimately arise, even if the vendor has previously sent each lot to an official seed lab. Planting certified blue tagged seed is the best insurance against noxious weeds, but most seed on the market is not put through the rigors of the seed certification program. Even if you have to plant the seed before the analysis returns, it is helpful to know for sure what you planted, and you will still have time to negotiate payment with the vendor, or anticipate a noxious weed spray program if necessary. Also, if you requested blue tagged certified seed, you can certainly ask for the blue tags to be sent to you along with the seed.

If you wish to test your seed for purity, germination or noxious weed content you have two options. You can sample your own seed or call an official State seed sampler to draw a sample (see name below for your county). Since there may be a dispute with the seed supplier, it is better to have an official sample, but your own sample will hold weight if you follow the sampling guidelines. The Ag Department official will draw a sample and send it to your State seed lab asking for a purity test, which includes a check for noxious weeds as well as common weeds (some of which can be more harmful than certain noxious weeds). The purity test will also tell you whether your mix has been adulterated with a cheap filler, such as annual ryegrass. Purity and weed tests take only a few days, and the lab will fax the results if requested.

You may also request a germination test or a TZ test (a quick test for viability.) It can take up to 30 days for germination tests to be completed, so if you need a quick estimate, ask for a Tetrazolium (TZ). Some seed companies play the "tolerance game," and routinely raise the numbers in their computer program that figures how many bulk pounds are needed to supply the requested PLS pounds. E.g., If you order 1000 PLS pounds and the vendor's lab test shows 90% pure by 87% germ, but they enter 95% by 92% in their software, you will get only 1144 bulk pounds instead of 1277 pounds owing to you according to the lab test.

If you take your own sample, follow this procedure:

  • For lots of 1 to 6 bags, sample each bag;

  • For lots of more than 6 bags, sample 5 bags plus at least 10% of the number of the bags in the lot.

Plunge your hand into different areas of the bags, placing the handfuls into a sample bag. Box the sample(s) to avoid damage in the mail, enclose your instructions, and send to the seed lab. Labs can be located by contacting your local Ag Extension office or state university. Avoid leaving the sample on the dashboard of your truck, since temperatures over 130 degrees F will kill seed.


EXAMPLE OF INSTRUCTIONS TO LAB: "Please test for purity, noxious weeds, TZ"

Fax test results to..........................................

Fax number...............................

Send invoice to....................

Enclose a copy of the bag label with these instructions for the lab to compare with their results.


When the test returns, you may want to phone the lab for aid in comparing the test results with the seed tag. The results may be close or way out of tolerance. If the state official samples the seed, they will have guidelines about acceptable tolerances.




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