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National Seed Laboratory - Frequently Asked Questions

We have compiled some of the most frequently asked questions  with their answers below.  If you need more information that what is posted here, please feel free to contact us for more specific information.

How should I package seed to be sent to the National Seed Lab?

Seed should be in moisture proof bags (sandwich bags work well) and packaged in a box with packing material so that the chance of damage during shipment is minimized.

How much seed do I need to send?

Tests conducted by the laboratory can only evaluate the quality of the submitted sample and it is essential that the submitted sample represent the entire seed lot. The Association of Official Seed Analysts (AOSA) and the International Seed Testing Association (ISTA) have minimum working weights for purity analysis based on 2500 seed. Samples submitted to the NSL should contain at least 2500 seed. If a moisture content analysis is needed, extra seed is required. Seed per pound, germination, x-ray analysis, tetrazolium, and excised embryo tests are conducted using pure seed from the purity analysis. If a purity tests is not required, fewer seed can be submitted. Analysis, of seed lots, for International Seed Testing Association (ISTA) certificates, have additional requirements. Please contact the NSL for further information regarding ISTA certificates.

 Seed Per PoundMinimum Sample Size
Small sized seed>20,0001-2 ounces
Medium sized seed10,000 - 20,0003-5 ounces
Large sized seed<10,0005-10 ounces or more depending on size

How long does it take to test tree seed?

Depending on the tests conducted and species being tested, testing can take a few days to several months. Moisture content, purity, seed per pound, x-ray and tetrazolium tests can be finished within a few days on most species. Excised embryo tests take two to three weeks. Germination tests of tree and shrub seed requirea minimum of four weeks. Many species require weeks or months of pretreatment to overcome dormancy or increase speed of germination prior to the four week minimum germination period. In addition, during certain times of the year, the laboratory receives large numbers of samples. There may be a delay between when we receive the sample and when we begin the tests.

How do I pay for seed tests?

The National Seed Laboratory will send you an invoice for services performed. We can bill you annually, quarterly, or each time you send seed to the laboratory. Let us know what is best for your situation. Please include the Federal ID Number of the invoice agency on the Seed Test Request Sheet.

Does the NSL accept credit cards?

Yes. You can now pay your bill, for seed testing, online with a credit card or by check at the billpay website.

Where can I get a copy of the required Seed Test Request Sheet?

Seed Test Request Sheet