We routinely perform the following seed tests at the J & T Green Seed Services Lab:

Purity Analysis Testing

"The analysis is performed, on the kind in question, to determine the percentage of pure seed, other crop seed, weed seed and inert material present in the seed lot." - AOSA Rules for Seed Tesing

A purity analysis test is performed by separating the sample into four components: pure seed, other crop, weed, and inert material. Our Registered Seed Analyst uses a binocular stereoscope or a magnifier (depending on the seed size) to aid this process as he separates the sample into the four components.  Each component is weighed and a percentage of the whole is derived. Weeds and other crop seed must be identified and recorded on the purity analysis report.

Noxious Weed Examination

All samples given a purity analysis will also receive an examination for noxious weeds seeds if requested.  Seedmen should request an examination for the noxious weeds for all the states the seed lot will be shipped to. The cost for this service is in addition in the purity charges.

This test is performed on a larger sample than that for a purity analysis and only noxious weeds on the Federal and State noxious weed seed lists are identified and reported.

There is no extra charge for additional states requested or for an "ALL STATES " exam.

Germination Testing

Seed germination in our laboratory is defined as "the emergence from the seed embryo of those essential structures which, for the kind in question, are indicative of the ability to produce a normal plant under favorable conditions." - AOSA Rules for Seed Testing

An "official test" of 400 seeds are always planted for our standard germination test.  Depending on seed size, four to eight replicates may be routinely used.  Seed is either planted by hand, counting board or the lab's vacuum planter is used. Many different types of substrate are used for our germination tests.  Blotters, towels, and filter paper are the most common that we use.

Seed germination tests are then placed into a growth chamber.  Chambers are set at various temperatures, and some even alternate temperature during the day to simulate natural germination conditions. As soon as the seeds develop structures particular to the species being tested, we can evaluate them.

Just because a seed sprouts does not mean it is counted as having germinated.  All the proper structures must be present and capable of continued growth for the seed to be considered normal.  When evaluating, our analysts separate the sprouted seed into four categories: normal, abnormal, dead, and dormant (a TZ test is used to determine dormancy).

All ungerminated seeds at the end of the test are examined for dormancy with tetrazolium testing...

Tetrazolium (TZ) Testing

When a quick estimate of the total viability is needed, a tetrazolium test should be requested. The test usually takes 24-48 hours to complete, but with native species this may take 48 hours or longer.

In the tetrazolium test, seeds are imbibed in water overnight, and then bisected (or pierced) with a razor blade.  The seed is placed into a TZ solution to stain. As the seed respirates it reacts with the TZ solution.  The parts of the embryo that are dead have no reaction.

With live seed tissue, a chemical reaction takes place. Live structures in the embryo stain red.  Once the seed has stained (this can take 2-48 hours, depending on the species) the analyst 'evaluates' the TZ staining patterns and determines the percentage of viable seeds in the seed lot.

Additional Seed Tests

Additional seed tests can be found on our price list or you can call us to see if we perform the test you want.