When you interpret germination rates from your seed test, the percentage tells you what fraction of your seeds will sprout when planted. A 90% result means about nine out of every ten seeds should come up in your garden. These numbers help you decide whether to use your existing seeds or buy fresh ones before planting season starts.
I use my test results to sort seeds into three groups every spring. The high performers go straight into my planting trays with no changes needed. The middle group needs thicker sowing to fill the rows. The low performers get tossed in the compost rather than wasting garden space on seeds that will mostly fail.
The germination percentage meaning comes from a simple math formula you can do in your head. Count how many seeds sprouted in your test. Divide that by the total number you tested. Then multiply by 100 to get your percentage. If 18 out of 20 seeds sprouted, that gives you 90% germination.
Your seed germination results in the excellent range mean no changes to your normal planting plan. Seeds at 90% or higher will fill your rows with strong, healthy plants. Space them as the packet says and expect good stands without any bare spots. These are the seeds to save for your most important crops.
Good results between 70% and 89% still give you plenty to work with in the garden. The trick is sowing a bit thicker to make up for the seeds that will not sprout. If you would normally plant 10 seeds per foot, bump that up to 12 or 13 instead. You will thin out the extras after they come up.
Marginal seeds in the 50% to 69% range put you in a tough spot as a gardener. In my experience, these seeds often produce weak plants even when they do sprout. I replace them for crops where strong growth matters, like tomatoes or peppers. For easy crops like beans, I might sow double and hope for the best.
Your viability test results below 50% mean those seeds belong in the compost bin. Even sowing triple the normal amount will leave gaps in your rows. The few plants that do come up may grow slow and struggle all season. Buying fresh seed costs less than wasting weeks of growing time on poor performers.
Keep your test numbers written down in a notebook or spreadsheet for future reference. Track each variety with its test date and result. Over time you will learn which seeds hold up well in your storage setup. This record helps you plan when to replace varieties before they fade too far to use.
Read the full article: Seed Viability Test Guide: Ensure Your Seeds Grow
