How to Read a Grass Seed Label

Choosing the best grass seed for your lawn projects can seem overwhelming when you're faced with so many choices in local stores. Differences in packaging, products and applications can complicate even the simplest comparisons. The bag itself provides important information about the product, the technology behind it and the types of projects it suits best, such as patching and repairing or seeding new lawns. But labels aren't the only way to determine the best investment for your time and money. Products also carry seed tags to tell you more about what's inside the package.

What Is a Seed Tag?

Every bag of seed in your local store has what's known as a seed tag or seed-analysis tag attached. Thanks to the Federal Seed Act1 and state seed laws, every seed product must carry standard, uniform information to prevent misrepresentation and help consumers make informed choices.

On bags weighing 15 pounds or less, seed tags are usually printed on the back of the bag, at the bottom. On larger bags, tags are sewed into the bag's top seam. On jugs of seed, you'll find the seed tag printed on the side panel. Understanding a seed tag isn't very complicated once you learn what it provides.

What a Seed Tag Tells About Grass Seed

Information on every seed tag is based on actual testing of the seed product. Every item of information equips you to choose the cleanest, purest, highest quality seed for your needs. Formats vary, but every seed tag provides the following:

1. Seed Product Name: This is the brand name, and it's usually the first item on the tag. On Pennington products, you'll find names such as One Step Complete for Sun & Shade Areas or Pennington The Rebels Tall Fescue Blend Keep in mind that mixes contain more than one grass species, and blends contain different varieties of the same grass.

2. Net Weight of Bag/Container

3. Pure Seed: Purity indicates the percentage by weight of each grass variety and kind named. The percentages reflect the quantity of pure grass seed versus other contents in the bag.

Seed tags may list several lines under the Pure Seed heading. Varieties with the highest percentage are listed first. The total of all the percentages under this heading reveals what percentage of the bag's contents are pure seed.

4. Variety and Kind: Each line of pure seed lists the variety and kind of seed next to its purity percentage. Kinds of grass are general species, such as Tall Fescue, but varieties are grasses that exhibit distinct characteristics in areas such as performance or appearance that distinguish them from other grasses of the same kind. Knowing variety names can help you match your lawn's specific needs.

Kinds are similar to apples versus oranges, while varieties are akin to Granny Smith versus Red Delicious. For example, Mallard Kentucky Bluegrass listed as the variety and kind lets you know you're getting more than standard bluegrass. The Mallard variety identifies an award-winning, drought-tolerant grass developed through Pennington-affiliated research and breeding programs.

VNS on a seed tag stands for “Variety Not Stated," which typically refers to lower cost, lower quality seed. Premium grass seed generally relies on exceptional named varieties, but VNS seed can contribute to quality seed products.

5. Germination Rate: For each pure seed variety and kind, the germination rate reflects the percentage that germinated under laboratory conditions during testing on the seed lot. This is the percentage you can expect to germinate and produce normal, healthy seedlings under optimal conditions.

Pure seed percentages reflect quantities by weight, but germination rates indicate potential performance.

6. Origin: Seed tags list the state, U.S. possession or foreign country where each named pure seed was produced or propagated.

7. Other Crop Seed: Any seed that comprises 5% or less of the product by weight can go unnamed. Smaller seed amounts, other than pure seed and weed seed, are combined in this percentage.

8. Inert Matter: Seed products can contain non-seed materials as a natural occurrence of cleaning and processing seed. Inert matter reflects the percentage of these materials, such as sand, soil, stem pieces and seed parts. In all-in-one products, such as Pennington One Step Complete, this percentage also includes the product's beneficial mulch and fertilizer. Tags on these products provide a breakdown of these inert ingredients.

9. Weed Seed: This item reflects the percentage by weight of seeds found during testing that your state considers weeds. This is seed other than pure seed and other crop seed. Weed designations vary from state to state.

NOTE: The percentage of all pure seed, other crop seed, inert matter and weed seed should always equal 100%.

10. Noxious Weeds: Noxious weeds are categorized by state and listed separately on the seed tag. Noxious weeds are regulated and may be restricted or prohibited from state to state. Seed tags note the name and the number of seeds found per pound during testing. This is different than the other items on the seed tag that are calculated by percentage of total package weight.

11. Guaranteed Analysis: Seed tags on all-in-one, fertilizer-inclusive products include a guaranteed analysis of the fertilizer and soil amending ingredients. To help consumers compare products easily, all fertilizer product labels carry three numbers denoting the fertilizer's N-P-K ratio — the proportion of the nutrients nitrogen (N), phosphorus (P) and potassium (K). These numbers reflect each nutrient's percentage by weight. Learn more about understanding fertilizer information from Pennington Fertilizer by reading Numbers to Grow By: Understanding Fertilizer Labels.

12. Lot Number: This permanent identification number traces the seed back to a specific batch that was processed and tested. Test results apply to all seeds that were part of that lot.

13. Test Date: This date indicates when the seed lot was tested for germination. Seed germination rates drop over time, even under optimal storage conditions. However, lots can be retested and "over-stickered" with a new seed tag if the germination rate meets the label guarantee.

14. Sell By Date: Each state allows seed to be sold for a fixed number of months after the initial testing or retesting. Allowances vary, and some states require tags carry "sell by" dates. Seed tags include these dates alongside state-specific listings.

15. Name and Address of the Seed Company

Putting Seed Tag Information to Use

Seed tag information underscores the value of superior grass seed, but it also determines how much seed you actually need. Seeding recommendations are based on what's called Pure Live Seed (PLS). A product's PLS reflects pure seed percentages and germination rates. Planting rates on Pennington Seed packaging take PLS into account, so package directions show the amount of seed you need based on tested germination rates, but not all seed packaging does.

With a good understanding of seed tag information, you can see beyond the bag to the integrity of the seed inside. Seed tags on premium, purebred Pennington Smart Seed and the full line of Pennington's grass seed products help you feel confident you're getting the best value and the best quality seed for your project.


1. U.S. Department of Agriculture Agricultural Marketing Service, Federal Seed Act, issued March 1940, amended August 1988, revised April 1998.

Pennington, Pennington 1 Step Complete and Smart Seed are registered trademarks of Pennington Seed, Inc.