Understanding Seed Packet Information | Decode Every Label

That crumpled paper envelope in your hand is the most important gardening tool you didn’t know you owned. One wrong interpretation — mistaking packaging date for harvest date or assuming “heirloom” means “organic” — can send a season sideways. Here’s how to pull every useful fact off a seed packet on first read.

What The Front Of The Packet Tells You

The front is the identity card. It displays the plant’s common name and its specific variety or cultivar — the cultivated form bred for consistent traits. Below or beside the name, you’ll see the seed company’s branding and a photo meant to represent the mature plant. Three quality labels often appear here: Organic (produced under USDA organic standards), Heirloom (a variety passed down through generations), and Hybrid (a deliberate cross that usually will not breed true from saved seed). None of these terms are interchangeable, and a packet can carry none, one, or all three.

If the label says Open-Pollinated, it means the seed will produce plants nearly identical to the parent — the key trait that makes seed saving viable. Hybrid seed, by contrast, is bred for hybrid vigor and uniformity in that single generation; saved seed from a hybrid tomato might give you a small, bitter fruit or nothing like the original. Most first-time gardeners buy their seed starting collection from a well-stocked supplier. For bulk quantities, check out our roundup of top-rated bulk seed packets for any garden size.

Reading The Back: Growing Instructions And Legal Data

The back of the packet is the manual. The first line tells you the two most time-sensitive facts: days to germination (how long before you see sprouts under ideal conditions) and days to maturity (how long from planting to harvestable crop). Maturity counts from transplant or direct sow — the packet may specify which. These numbers are averages; cool soil or low light can double them.

Next comes the sowing depth and spacing block. Depth matters because seeds need the right light or darkness to trigger germination; covering a lettuce seed with half an inch of soil buries it too deep. Spacing instructions tell you the final distance between mature plants — ignoring this is the most common cause of crowded, weak seedlings. Look also for the seed count or weight, usually printed nearby. Not every packet lists it, and the format varies by state law, but when present it tells you exactly how much growing material you hold.

Treatment, Testing, And Quality Codes

Seed packets use a handful of shorthand labels that carry legal weight. Untreated means no fungicide or insecticide coating has been applied — critical for organic growers and anyone eating microgreens. Treated seed is usually coated with a fungicide, often dyed a telltale pink or blue so you can spot it in the bag. The germination percentage is a lab-tested estimate of how many seeds in that lot should sprout; 85% or higher is standard for most vegetables. A test date within 12 months of your planting season means the number is still reliable — Oregon State University’s extension service recommends confirming this before buying leftover packets.

The lot number is a tracking code that lets the seed company trace that packet back to its field origin and lab results. It matters only if you have a problem and need to file a complaint, but its presence shows the packet came from a regulated producer. Some state labels also list pure seed percentage, inert matter, and weed seed content — these are required on agricultural-grade seed but appear less on retail packets.

Germination Terms And What They Actually Mean

The germination percentage on the packet is measured under controlled lab conditions — warm, moist, consistent — not your garden soil. A label showing 90% germination means nine out of ten seeds sprout in that ideal environment; in cold clay soil, expect fewer. Some packets also report hard seed (seeds that remain dormant until scarified) and dormant seed (viable but not yet triggered to grow). These numbers matter most for native wildflower or perennial mixes rather than common vegetables. The TZ test (tetrazolium) is a chemical viability check used for slower-germinating species — if you see “TZ” on a label, the percentage reflects the seed’s potential to sprout over time, not the two-week count a standard germination test measures. USDA/industry guidance recommends that the test date on any seed packet be within 12 months of your planned planting date for the most reliable results.