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Seed Definitions

This directory has been compiled to make it easier to find businesses that sell native plants or seeds and provide professional landscape or consulting services. Use the search options below to find help for your native plant needs or click here to add your business to the directory. Associates offer Wildflower Center members a discount on merchandise or services.

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Certified Seed - This certification only applies to seed produced through cultivation, not seed collected in the wild. The seed certification system promotes the production and purchase of seed of known genetic identity and is used widely in the traditional agricultural field. Only cultivated, named varieties can be certified. Each state has a certification agency that inspects field conditions and regulates how the seed is produced, harvested, and cleaned. The seed is also subject to a variety of laboratory tests. If the seed passes these tests, it is certified by a state agent with a BLUE tag. This certification process guarantees the seed has the same genetic potential to perform in the field as the original seed did when it was released for production. This type of seed will only be available from the larger seed companies. Sometimes it is necessary for native seed suppliers to cultivate native seeds if the amount of seed needed is greater than what could be harvested in the wild without impacting native populations. However, it is important to consider how growing all the seed together in a cultivated area may have altered the genetics of the seeds. They may no longer be as adapted to the environmental conditions they may experience on your planting site.

Source Identified Seed - The Association of Official Seed Certifying Agencies (AOSCA) has an approved seed certification class for native seed collection called the “Source Identified Class.” Seed that was harvested following approved guidelines for this seed class will receive a YELLOW certified seed tag which verifies to the purchaser that the location of seed harvest was verified by the certifying agency. This yellow certification is not available yet in all states.

Pure Live Seed (PLS) - Pure live seed is a measure describing the percentage of a quantity of seed that will germinate. It is a way to standardize quality so the purchaser can compare the quality and value of different lots of seed. One lot may be cheaper, but may not have as high a PLS as another lot, and so therefore may not be a better deal financially because it would have fewer seeds that would actually germinate.

Seed Testing and Labeling - Seed companies should include a clear label on each bag of seed that shows the results of purity and germination tests. The Association of Official Seed Analysts oversees these tests. Purity of the seed is the percentage of the labeled species by weight. The percentages of other crop, weed, inert material, and the percentage of dormant or hard seed should also be included. The label should also show the percentage of the seed count that will germinate. Keep in mind however that many seed labs are still not that familiar with native seeds’ germination requirements and so may not accurately estimate the germination percentage.

Customized Mixing - Some companies offer custom seed mixing services that involve creating a seed mix from species chosen by the customer. However, the drawback of purchasing pre-mixed seeds is that it becomes difficult to confirm the purity and quality of the seed you are purchasing.

Site Adapted Custom Seed Collection - Some seed companies also may offer collection services where they will harvest seed from sites the customer specifies. This is a preferred way to go for many that want to ensure their seed is from local sources.

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