Seed Quantity Calculator
Seed Quantity Calculator
Uses target plants, expected germination and an extra seed buffer, then rounds upward.
Estimate seeds to sow from target plants, expected germination, and a buffer.
ceil((target plants ÷ germination rate) × (1 + buffer)).Worked example
For 20 target plants, 80% expected germination and a 15% buffer: 20 ÷ 0.80 = 25; 25 × 1.15 = 28.75; round up to 29 seeds.
Where the germination percentage comes from
Use the seed packet or a recent germination test when possible. Older seed lots can perform differently from fresh seed, and field emergence can be lower than a controlled germination test.
Do not confuse seed buffer with planting density
The extra percentage covers expected losses before you reach the target number of established plants. It does not mean crowding extra seedlings into the final spacing.
Use this for the full seed requirement
The tool first compensates for expected germination, then applies your optional extra buffer. Keeping those steps visible makes it easier to compare a fresh high-germination packet with older seed or a crop you intend to thin after emergence.