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Frequently Asked Questions

This Ecomap was provided by Texas Native Seed Project in Texas A&M Kingsville. 

Douglass King Seeds is a sponsor and producer of certified South Texas Native plant varieties. We are proud to support and work with the South Texas Natives and Texas Native Seeds projects at the Caesar Kleberg Wildlife Research Institute.

What Are Ecoregions?

An ecoregion is an area of land that is similar in habitat, geology, soil, and vegetation. Ecoregions are large, general groupings and there can be some variety within the region. As far as finding the right seed for your project, however, this is a great place to begin. The Texas Native seed species have the regions they perform best in list in the region section.

When is the best time to plant? 

Believe it or not, Spring isn't always the answer, although it is frequently one of the answers. Plants are broadly categorized into two categories, warm season and cool season, that denote whether they grow best when the temperatures are warm/hot, or when the temperatures are cool/moderate. 

Warm Season: Warm season loosely refers to the spring and summer. Typically warm season plants are planted in from March to June and August to October. These plants are not frost tolerant and will either have slow growth or  stop all together during cool/cold weather.

Cool Season: Cool season loosely refers to the fall and winter. Typically cool season plants are planted between September 15 to December 31. These plants are frost tolerant or tolerant of cool temperatures, which means they prefer to grow when the temperatures are moderate to cool.

What is PLS? 

PLS refers to Pure Live Seed and is a measure of how much whole, live seed is in an amount of bulk pound. Its a great way to measure the quality of seed you are buying. 

The PLS value is found by multiplying the percentage of purity against the percent of germination. 

Purity: how much whole seed is left after cleaning. For example, we subtract the broken seeds, stems, and hulls to find how much pure, whole seed is there.

Germination: how much grew when tested.

We send all of our seed to seed labs for these tests. Ask us, we can even show you the lab reports! 

Pure Live Seed (PLS):   is the percentage of viable seed in a given lot and is calculated by multiplying the purity (B. the amount of whole seed in a sample) by the germination (C. how much seed grows when tested).

Pure Live Seed (PLS):  is the percentage of viable seed in a given lot and is calculated by multiplying the purity (B. the amount of whole seed in a sample) by the germination (C. how much seed grows when tested).

For example, a purity of 50% (the amount of whole seed) multiplied by 80% germination (how much seed grows when tested) equals 40% PLS. To put it simply, in one pound of this example seed, about 40% of it is pure live seed. So to get 1 lb. pls, you would have to use 2.5 lbs. of bulk seed from that example seed.  From another sample with a 82% pls, you would need 1.2 lbs. of bulk seed. 

How the planting rates are set: USDA sets the PLS-per-acre planting recommendations for each species of seed. We use this to guide how we help you design your project. For example, if you have one acre you would like to spread a grass seed on, and the grass seed you chose has a recommendation of 3 pls per acre, we can then look at the lots of seed we have available and gather a bulk quantity that will reach that pls level — and you are charged on how much viable seed you get, not just bulk pounds, which includes non seed items like stems and hulls.

Why is PLS important? Think of this similar to the octane rating on gasoline. Where one gallon of 87 gasoline costs less than one gallon of 92 octane, because for the same amount of volume, one has a higher fuel quantity. So comparing one pound of seed to another there might be a large difference as to how much whole viable seed is present. PLS corrects for that. Therefore you know when you buy seed with a PLS rating that it is of a certain quality and has a certain likelihood of growing. Like gasoline, you know how much "energy" is in that bulk pound.

Why not have the same amount of seed per pound across the board? Plants have variability and one season a field of grass might produce a lot of seed, then another season the same field might produce little seed or produce more stems and hulls than seed. And although seed processing is pretty refined, it cannot pull all the extra stuff out if those items are of similar size to the seed.

If you compare the two different harvests based on weight alone, you will get a different amount of live seed each time. Pricing on bulk weight alone is not fair to you, the consumer, who wants the same amount of plants from one year to the next. So we take the extra step to test all of our lots of seed to ensure you are getting the right amount of seed for your project. 

About Pasture and Rangelands (From

  • Rangelands are described as lands on which the indigenous vegetation is predominantly grasses, grass-like plants, forbs, and possibly shrubs or dispersed trees.   Existing plant communities can include both native and introduced plants.

    • Management of rangelands occurs primarily through ecological processes, rather than agronomic applications.

    • Rangelands comprise about 30% of the entire land cover of the United States, totaling about 770 million acres. About 2/3 of all U.S. rangelands are privately owned.  In the contiguous 48 states, privately owned rangelands make up about 409 million acres, 27% of the total land area, and form the largest single land cover/use type.

  • Pastures are a land use type having vegetation cover comprised primarily of introduced or enhanced native forage species used for livestock grazing.

    • Management of pastures is through periodic renovation and cultural treatments such as tillage, fertilization, mowing, weed control, and may be irrigated.  Pasture vegetation can consist of grasses, legumes, other forbs, shrubs or a mixture.

    • The majority of these forages are introduced, having originally come from areas in other continents.  Most are now naturalized and are vital components of  pasture based grazing systems.

    • Some common introduced forage species are tall fescue, orchard grass, red and white clover, and bermudagrass.  Some cropland and pasture land has been converted to native warm season grasses such as switchgrass, bluestems, indiangrass, and gamagrass.

    • Pasture lands are found in all states of the United Stated and its territories.  These lands comprise about 6%, or 119 million acres, of the contiguous 48 U. S. states.

The difference - Pastures differ from rangelands in that pastures primarily produce vegetation that has initially been planted to provide preferred forage for grazing livestock and is actively managed by tillage, fertilization, mowing, weed control, and sometimes irrigation. Whereas rangeland management occurs primarily through natural ecological processes, such as the weather or natural fire.

What is "germplasm"?


Germplasm is a scientific term for living cells that will germinate, or begin to grow. In other words — seeds. 

When you see the word Germplasm used on our website, it is a technical industry term referring to the specific genetic makeup, or strain of plant.

Our Texas Natives are certified "Selected Texas Native Germplasm" by the Texas Department of Agriculture. Each variety is of a specific ecotype of its species that was locally sourced from counties in Texas.

This certification process traces the lineage of that selection of plant to when and where it was sourced in the wild.