How Many Seeds Should I Save? Seed Saving Calculator
Saving your own seed is satisfying and cheap, but it is easy to save far too few, or far too many, of the wrong things. Not every saved seed will germinate, and not every seedling makes it to the garden.
Runs in your browser. Nothing you enter is stored.
What this calculator does
Enter the plants you want next year and your expected germination and establishment. The calculator works out the seeds to save with a safety reserve and how many pods, fruits or seed heads that means at harvest.
How to use the seed saving reserve calculator
- Optional: pick a crop to load typical seeds per pod or fruit and germination.
- Enter how many plants you want to grow next year.
- Set expected germination and the share of seedlings that survive to planting out.
- Add a reserve for re-sowing after failures, sharing with friends or keeping a backup.
- Read the seeds to save and the pods or fruits to set aside, and label them with the date.
How the calculation works
seeds needed = ceil(plants ÷ (germination % × establishment %)) seeds to save = ceil(seeds needed × (1 + reserve %)) pods or fruits = ceil(seeds to save ÷ seeds per pod or fruit)
Germination and establishment multiply together to give the share of seeds that become a plant. The reserve sits on top of that so one poor season does not lose the variety.
Worked example
For 24 bean plants with 80% germination and 85% establishment, you need 36 seeds. Adding a 50% reserve, save 54 seeds, or about 11 pods at 5 seeds per pod.
Assumptions and limitations
- Seeds from F1 hybrid varieties do not grow true to type. Save seed from open-pollinated or heirloom varieties.
- Cross-pollinating crops such as squash, corn and brassicas need isolation or hand-pollination to stay true. Some crops also need seed saved from many plants to keep the variety healthy.
- Seed viability declines with age and depends on the crop and storage. Keep seed cool, dry and dark, and germination-test older seed.
Frequently asked questions
How many seeds should I save for next year?
Divide the plants you want by your expected germination and establishment rates, then add a reserve. For most home gardens a 50–100% reserve is plenty.
How long do saved seeds last?
It varies by crop and storage. Many vegetable seeds stay viable for 2–5 years when kept cool, dry and dark; onions and parsnips are shorter-lived.
Can I save seeds from hybrid plants?
You can, but plants grown from F1 hybrid seed usually differ from the parent. Open-pollinated and heirloom varieties come true from saved seed.
How do I test germination of saved seeds?
Place 10 seeds on a damp paper towel in a bag somewhere warm, check after the usual germination time and count how many sprout. Seven sprouts means about 70% germination.