Seed Germination Test Calculator & Is Your Seed Good?
Grades cereal seed
Turn a simple germination test into a germination percentage and verdict — plus the pure-live-seed value, expected field emergence, and the adjusted seed rate to still hit your plant stand.
Tip: count 100 seeds onto damp tissue/soil, keep warm and moist, and count how many sprout after the species' test period (often 7–10 days).
88 of 100 seeds sprouted — a germination of 88% (Good). Meets most certified-seed standards — sow with a small rate bump. Expect somewhat less in the field (around 74.8%) than on the test tray.
Next: add your base seed rate above to get the adjusted kg/ha that hits your target stand despite this germination.
A simple ragdoll/tray test — use a larger sample (200–400 seeds) and the official test period for more reliable figures.
Seed germination — key facts
- Formula
- germinated ÷ tested × 100
- Excellent
- ≥ 90%
- Certified-seed standard
- ≈ 80–85%+
- Reject below
- ~50%
- Pure live seed
- germ% × purity% ÷ 100
- Field emergence
- ≈ 85% of lab germ
- Sample size
- 100–400 seeds
- Privacy
- Runs in your browser; nothing uploaded
Why test germination before sowing
Seed is the cheapest input but the one that decides your whole stand — sow a weak lot at the normal rate and you get gaps, uneven maturity and lost yield that no later input can recover. A quick germination test on a counted sample tells you the share of seeds that will actually grow, and the verdict tells you whether to sow it, bump the rate, or replace it. The tool also estimates pure live seed and likely field emergence, which is always a little below the cosy test-tray figure.
Where germination is below 100%, you simply sow proportionally more to reach the same plant population: at 80% germination you need 25% extra seed. Entering your base seed rate and purity gives the exact adjusted kg/ha, so you neither waste expensive seed nor end up with a thin crop. Test carryover seed every season — viability falls with age and warm, humid storage.
Check a seed lot
Get the germination % and an instant verdict on whether the lot is fit to sow.
Adjust the seed rate
See the kg/ha to sow so a less-than-perfect lot still reaches your target stand.
Compare lots fairly
Use pure live seed to compare seed lots on equal terms before buying.
Plan field emergence
Allow for the drop from lab germination to real-field emergence in your stand.
Frequently Asked Questions
How do you calculate germination percentage?+
Divide the number of seeds that sprouted by the number of seeds tested and multiply by 100. If 88 of 100 seeds germinate, that's 88%. This tool does the maths and grades the result so you know whether the lot is fit to sow.
How do I run a germination test at home?+
Count out 100 seeds, space them on damp paper towel or tissue (the 'ragdoll' method) or in moist seedling mix, keep them warm and moist out of direct sun, and count how many sprout after the species' normal test period — often 7–10 days. A larger sample of 200–400 gives a more reliable figure.
What is a good germination percentage?+
Above 90% is excellent, 80–89% is good and meets most certified-seed standards, 70–79% is fair but worth bumping the seed rate, and below 70% is poor. Below about 50% the lot is usually not worth sowing — source fresher seed.
How do I adjust my seed rate for low germination?+
Divide your normal seed rate by the germination fraction. At 80% germination you need 100 ÷ 0.80 = 125% of the normal rate to reach the same stand. Add the purity percentage too for the full pure-live-seed adjustment — this tool computes the adjusted kg/ha for you.
What is pure live seed?+
Pure live seed (PLS) combines germination and purity: PLS% = germination% × purity% ÷ 100. It's the fraction of a seed lot that is both the right species and able to grow, and it's the fairest basis for comparing and pricing seed lots.
Why is field emergence lower than the test result?+
A germination test is done in ideal warmth and moisture. In the field, crusting, cold or dry soil, sowing depth, pests and disease all reduce the share that emerges — often to roughly 85% of the lab figure. Plan seed rate around field emergence, not just lab germination.
Does germination decline as seed ages?+
Yes — viability falls over time, faster in warm, humid storage. That's why it's worth testing carryover seed before each season rather than assuming last year's rate, and why cool, dry storage extends seed life.
What is seed purity?+
Purity is the percentage by weight of a lot that is the intended seed, the rest being other crop seed, weed seed and inert matter (chaff, soil). High purity means you're paying for, and sowing, mostly viable crop seed rather than contaminants.
Can I use this for any crop?+
Yes — the germination percentage and seed-rate adjustment work for any seed, from cereals and pulses to vegetables and grasses. Just use that crop's normal test period and base seed rate.
How does this relate to the seed rate calculator?+
This tool tells you the germination and the adjusted kg/ha; the Seed Rate Calculator turns a target plant population and spacing into a base rate. Use them together: get the base rate there, then adjust it here for your lot's germination and purity.