How many seeds will you need?
Start with the plants you want. Add your germination and survival estimates.
Using your rates
56 seeds
Target × (1 + reserve ÷ 100) ÷ (germination ÷ 100 × survival ÷ 100), rounded up once at the end.
Editable example
Example: 40 plants, 80% germination and 90% survival need 56 seeds with no extra reserve.