Germination Rate Calculator

How to Use This Calculator

Count out a sample of seeds (100 is ideal for easy percentage conversion), place them between moist paper towels, and wait 7-14 days. Enter the number tested and the number that germinated. Optionally enter a target seeding rate to see the adjusted rate needed to achieve your desired stand.

Why This Matters

Seed germination declines with age, poor storage, and mechanical damage. Planting seed with unknown germination rates leads to either thin stands that reduce yield or over-seeding that wastes money. A simple test before planting saves both.

Methodology

Germination rate (%) = (Seeds germinated / Seeds tested) × 100. Adjusted seeding rate = Target rate / (Germination rate / 100). This ensures enough viable seeds are planted to achieve the desired final population even with reduced germination.

Common Mistakes to Avoid

• Testing too few seeds — fewer than 50 seeds gives unreliable results due to sampling error.
• Not maintaining consistent moisture and temperature during the test, which skews results.
• Assuming last year's germination rate still holds — seed viability drops significantly with improper storage.
• Ignoring field emergence rate, which is typically 5-15% lower than lab germination due to soil crusting and pests.