How to Read a Turfgrass Seed Analysis Label
Your objective in purchasing and installing turfgrass seed is to establish a high-quality, beautiful and useful lawn.
To accomplish that you must start with high-quality seed of the varieties of turfgrass species that will best fit your geographic area, the microclimates of your property, your intended uses for the lawn and your long-term turfgrass maintenance program.
Proper site preparation, installation procedures and post installation care will all contribute to the success of your new lawn.
To achieve your desired results you must start with quality seed. All the seed quality information is listed on the seed analysis label.
To help you make the best choice, here are tips on how to read and interpret that label. (See the sample label posted as a separate document.)
By Federal law, the following information must be listed on the seed analysis tag:
The name of the seller: Here, ABC Turfgrass Company is the seller. The address is provided as well. You’ll want to keep this information for future purchases or in case problems occur.
Lot number: Each lot of grass seed must be numbered. Keep a copy in event problems should develop, the supplier can use this lot number to track details about the origin of the seed(s).
The seed variety or varieties of the turfgrass species: Here, Some name is the variety of one specie (Kentucky Bluegrass) and Other name is the variety of another specie (Perennial Ryegrass).
Named varieties of a species exhibit specific performance and aesthetic qualities. Seed identified only by the species - without noting the variety - gives you no option to match the variety’s qualities to what you want for your lawn.
Purity (listed as Pure Seed): This is the percentage, by weight, of each seed component (listed by variety/species) within the bag.
Purity doesn’t refer to seed quality, only quantity for each type of seed.
This sample is a seed mix, containing more than one species of seed. A mix could have multiple varieties of one or more of the species.
A seed blend contains more than one variety of a single species.
Germination percentage: This is the percentage of each seed component (listed by variety/species) that is capable of germination (the beginning stages of growth for a plant developing from its seed).
The germination figure is determined following precise laboratory procedures under conditions that are nearly ideal in temperature and moisture.
The conditions outdoors, in your lawn, will be more challenging, so you want a high percentage here.
Pure Live Seed (PLS) is a term used to show how much of that seed will be capable of germination based on each seed variety’s purity and germination percentages.
The formula is: PLS = % of Germination x % of Purity ÷ 100.
On this sample seed label, for Some name Kentucky Bluegrass:
PLS = 75 x 90 ÷ 100 for a total of 67.5 %.
For Other name Perennial Ryegrass:
PLS = 23.25 x 87 ÷ 100 for a total of 20.23 %.
If the seed were in a 100 pound bag, that would mean that out of 75 pounds of Some name Kentucky Bluegrass, only 67.5 pounds would be capable of germination.
If the same seed were in a 5 pound bag, of the 3.75 pounds of Some name Kentucky Bluegrass, only 3.38 pounds would be capable of germination.
Date: This is the date when each of the seed components within this lot was tested for germination.
The germination percentage typically drops as the seed ages so seed older than 9 to 12 months may be less viable than fresh seed.
The minimum purity and germination is guaranteed by law and varies by species.
Other Crop Seed: Crop seed refers to any seeds which are grown as an agricultural crop, such as bent grass, tall fescue, or wheat.
If any species of crop seed is greater than 5% by weight, it must be listed by species. All of the crop species less than 5 % by weight are included together as one percentage figure by weight.
Depending on the species involved, these crop seeds could cause more problems for your young lawn than weed seeds.
Weed Seed: This is the percentage, by weight, of all the seeds in the bag that are not identified as either pure seed or other crop seed. The lower the percentage number, the better the seed.
Noxious Weeds: The weeds classified as noxious are those weeds that are very difficult to control, and noxious weeds vary from one state to another.
They will be listed as the number per pound or per ounce found in the seed lot. None found is what you want to see here.
Inert Matter: This is the percentage, by weight, of all the material in the bag that is not seed. It could include anything from soil to seed parts such as chaff.
You want a very low percentage of inert material, because you’ll be paying for it along with the seed.
Origin: The state of origin for each variety/species is all that is required here.
Certified seed takes all this a few steps further, with specific production, field, laboratory, and packaging standards and strict inspections all required to maintain varietal purity.
There are two levels of certification: Blue Tag and Gold Tag (or sod quality). Each has specified additional requirements by species, for percentages of purity and germination, and more stringent restrictions on other crop and weed seeds.
When available, a bag of turfgrass seed with Blue Tag or Gold Tag certification will cost more, but will be well worth the price.