Seed Starting Calculator
Fill in the values and the answer updates as you type.
How the Seed Starting Calculator works
Seeds to sow = plants wanted ÷ (germination rate × survival rate), rounded up. The germination rate is printed on most seed packets, and old seed usually germinates worse. Example: with the default values, 20 plants at 80% germination and 90% survival need 28 seeds.
Inputs and results
The Seed Starting Calculator takes 3 inputs and gives 3 results.
What you enter
- Plants wanted — starts at 20.
- Germination rate (%) — starts at 80.
- Survival after transplanting (%) — starts at 90.
What you get
- Seeds to sow
- Expected seedlings
- Expected final plants
Example: Seed Starting Calculator with the starting values
With plants wanted 20, germination rate 80 % and survival after transplanting 90 %, the calculator returns:
| Seeds to sow | 28 |
|---|---|
| Expected seedlings | 22.4 |
| Expected final plants | 20.2 |
Change any value above and the results update straight away.
Seed Starting Calculator FAQ
How do I use the Seed Starting Calculator?
Enter plants wanted, germination rate and survival after transplanting in the fields, then read seeds to sow, expected seedlings and expected final plants in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Seed Starting Calculator calculate?
How many seeds to sow to end up with the plants you want. It returns seeds to sow, expected seedlings and expected final plants from the 3 values you provide.
What values does the Seed Starting Calculator start with?
It opens with plants wanted 20, germination rate 80 % and survival after transplanting 90 % so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Seed Starting Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Seed Starting Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.