GARDEN FIELD BOOK / CAT12 / C12P5
SEED TESTING / A CLEARER COUNT
Seed Germination Rate Calculator
Enter how many seeds you tested and how many germinated. Calculate an observed percentage and, if useful, estimate how many seeds to sow for a target count under the same test rate.
01 / YOUR OBSERVED SEED TEST
Enter your seed counts
Use counts from the same seed lot under a comparable test method. Add more samples if you tested separate batches.
02 / YOUR RESULT
Germination rate
Weighted across all included samples using actual seed counts.
Assumes the same observed rate; not a field-emergence prediction.
| Sample | Tested | Germinated | Rate |
|---|
THE METHOD
How the percentage is calculated
Record how many seeds were included in each completed test. Do not enter a package size unless every seed was tested.
Count seeds that germinated using the same observation criteria and test period for each sample.
Divide total germinated by total tested. A small test and a large test should not receive equal weight.
Observed germination rate (%) = total germinated ÷ total tested × 100
For example, 18 of 20 seeds germinated: 18 ÷ 20 × 100 = 90%. If the target is 45 germinated seeds, 45 ÷ 0.90 = 50 seeds as a conditional arithmetic estimate. An estimate is not a promise that 45 plants will emerge in the garden.
INTERPRET THE RESULT
What a germination test cannot tell you
A 10- or 20-seed test is useful for an estimate, but it may not represent every seed in the packet. Test results can vary between runs.
Soil temperature, moisture, depth and handling can affect emergence. A laboratory or paper-towel result is not the same as successful seedlings outdoors.
If no tested seed germinates, the percentage is 0%. No finite target-based sowing count can be calculated from that observed rate.
References and Sources
Utah State University Extension: Collecting and Storing Seeds from Your Garden. Its germination-testing guidance explains counting germinated seeds and dividing by the number tested. This calculator performs arithmetic on counts supplied by the reader.