Reading Grass Seed Labels
Ever feel like you need a PhD to understand a seed label? Now you don't. This article is your key to deciphering these pesky labels, required by law to be attached to every bag of grass seed.
December 7, 2022
All seed is required by law to have an analysis label attached to the package. Here are some specifics on what the seed label numbers mean:
The lot number will contain codes to indicate where and when the seed was blended. The lot number can also be traced back to the original component tests and field history of the seed if more detailed information is needed. The name and address of the seed labeler will be on the tag and they will have this information on file.
% Purity is based on weight. If the seed is a mixture the % purity will be figured by the weight percentage of each component times the purity on the component seed test. The total of all component purity percentages added together is the total purity of the seed mixture. Note: Different species of turfgrass seeds vary greatly in number of seeds per pound and the percentage of components by seed count will be different than the percentage by weight.
% Germ is the result of germination tests conducted in a seed lab on each component sample (sample size determined by USDA standards). Seed germination tests must be updated periodically according to state and federal regulations.
Origin is the state or country (if outside the USA) where the seed was grown and harvested.
Other Ingredients are made up of other crop seeds or the percentage of seeds from any agricultural crop other than components listed under % Purity. Some other crop seeds in turfgrass can cause problems. Examples would be orchardgrass timothy and bentgrass. Quality seed will not contain any objectionable crop seed.
Inert Matter is the percentage of chaff stems or any other products that are not viable. Quality seed will have a low percentage of inert matter.
Weed Seed refers to any seed not defined as components or other crop.
Noxious Weed Seeds are invasive and defined by state laws. Many states have specific laws for labeling noxious (hard to control) weeds in lawn and turf seed including poa annua. Quality seed will always carry "none found" under this heading. It is best that seed be tested and labeled according to noxious weed laws in all states.
Date Tested refers to the month and year of the last completed germination test in an accredited seed lab.
In addition to the analysis label seed may also have a certified label (blue tag) which is issued by an official state agency. Three basic requirements are assured by the issuing agency for certified seed: the seed varieties are unique and stable in several years of production; the seed was harvested and cleaned under the official agency guidelines to insure varietal integrity; and the seed has met the official agency standards for purity and germination as well as crop weed and inert content.