How to Read a Grass Seed Label (What All Those Numbers Actually Mean)

Pick up any bag of grass seed and flip it over. You'll find a label — sometimes called a seed analysis tag — packed with percentages, dates, and terminology that can feel more like a chemistry exam than helpful buying information.

Most people ignore it entirely and just go by price or brand recognition. That's a mistake.

That label is actually one of the most useful tools you have for evaluating seed quality before you buy. Once you know what you're looking at, it takes about 30 seconds to tell a quality bag of seed from a poor one. Here's a plain-language breakdown of everything on it.

Pure Seed %

This is the percentage by weight of the actual target grass seed in the bag — the stuff you're paying for. In a blend or mixture, each grass variety will be listed separately with its own percentage. The combined total of all the pure seed percentages tells you how much of the bag is genuinely the grass you want.

A high pure seed percentage is a good sign. Look for bags where the named grass varieties make up the clear majority of the contents.

Take our Lifetyme Pro Athletic Kwik-Green label as an example. It lists seven named cultivars — Oahu Perennial Ryegrass, Finish Line Kentucky Bluegrass, Gateway Kentucky Bluegrass, and others — each with their own pure seed percentage. Added together, those named varieties account for nearly 99% of the bag. That's exactly what you want to see.

What to watch for: Bags that list grass varieties without naming specific cultivars — sometimes labeled "Variety Not Stated" or VNS — are a red flag. Named, specific cultivars have been bred and tested for performance. VNS seed is often older, generic stock that may not perform as well in your conditions.

Germination Rate %

This is the percentage of pure seed that germinated under controlled laboratory conditions. It tells you how much of the seed in the bag is actually viable and expected to sprout under good conditions.

Look for germination rates of 80% or higher for most cool-season grasses. On our Lifetyme Sun & Shade label, every variety listed carries a 90% germination rate — meaning 9 out of 10 seeds of each variety are expected to germinate under good conditions. That's a strong number and a good benchmark to compare against other products on the shelf.

Pure Live Seed (PLS): Some labels include a PLS calculation, which multiplies the pure seed percentage by the germination rate to give you the true percentage of seed in the bag that will actually grow. This is the most honest measure of what you're getting. If PLS isn't listed, you can calculate it yourself: Pure Seed % x Germination % = PLS %.

Inert Matter %

Inert matter is everything in the bag that won't grow — seed coatings, chaff, stem pieces, sand, dust, and other debris that comes along with the cleaning and processing of seed. It's not harmful, but it's also not seed.

A low inert matter percentage means more of what you're paying for is actual seed. Look for bags with inert matter below 2% for quality lawn seed. Our Athletic Kwik-Green label shows 0.64% inert matter, and our Sun & Shade label shows just 0.48% — both well below the 2% threshold that separates quality seed from filler-heavy alternatives.

Other Crop Seed %

This is the percentage of seeds in the bag that come from agricultural crops other than the target grass — things like timothy, orchardgrass, bentgrass, or clover. In a lawn setting, these are essentially weeds. They'll germinate alongside your grass and produce plants you didn't want and didn't plant.

Quality grass seed should have other crop seed percentages well below 0.5%. Our Athletic Kwik-Green comes in at 0.21% and our Sun & Shade at just 0.17% — both well within the range of what premium seed should look like.

Weed Seed %

This one is straightforward: the percentage of weed seeds present in the bag. Even a small percentage can introduce a surprising number of weed plants into your lawn — weed seeds are often tiny and lightweight, meaning a small percentage by weight can represent a significant number of individual seeds.

Look for weed seed percentages at or below 0.3%. Our Athletic Kwik-Green shows 0.03% and our Sun & Shade shows just 0.01% — numbers that reflect the care that goes into cleaning and processing quality seed. If you see weed seed percentages above 0.5% on any bag, put it back.

Noxious Weeds

Noxious weeds are a category of particularly problematic plants regulated at the state level. The label is required by law to list any noxious weed seeds found in the bag by name and by number of seeds per pound. The best quality seed will read "None Found" in this section — which is exactly what you'll see on every Lifetyme Seed Company label. This is non-negotiable — never purchase seed that lists noxious weed seeds.

Test Date

This is the date the seed lot was tested for germination. Germination rates decline over time, even under ideal storage conditions. As a general rule, look for seed tested within the past 12 to 15 months. Both of the Lifetyme labels shown here carry a test date of April 2026 — current and fresh. Older test dates don't necessarily mean the seed is bad, but they do mean the germination rate on the label may no longer be accurate.

Sell By Date

Some labels — particularly smaller retail bags — also include a Sell By date, which varies by state. Our Sun & Shade 5 lb. bag lists Sell By dates by state, ranging from early 2027 to mid-2027 depending on where you live. This date is worth checking, especially if you're buying seed to store for future use.

A Quick Buyer's Checklist

When evaluating a bag of grass seed, here's what to look for at a glance:

• Named cultivars listed — not just "Variety Not Stated"
• Germination rate of 80% or higher per variety
• Inert matter below 2%
• Other crop seed below 0.5%
• Weed seed at or near 0%
• Noxious weeds: None Found
• Test date within the past 12–15 months

Why This Matters When Buying Lifetyme Seed

At Lifetyme Seed Company, we take seed quality seriously — it's been the foundation of our business for over 75 years. Every blend we produce uses named, tested cultivars selected for performance in Midwest conditions. When you pick up a bag of Lifetyme seed, the label reflects that commitment. You're not paying for filler, outdated varieties, or mystery seed — you're paying for seed that's been selected, tested, and blended to grow.

If you ever have questions about what's in a specific blend or want help comparing options, give us a call at 309-674-5153 or visit us at lifetymeseed.com. We're always happy to walk you through it.