Seed Rate Calculator

Calculate planting population, seed spacing, and sacks to order for corn, soybeans, dry beans, wheat, sunflowers, and other row crops. The Potato Seed tab handles seed piece weight, chip loss, and full cost estimation. Fully reversible — enter population to calculate spacing, or enter spacing to calculate population.

Frequently Asked Questions

Seeds per acre = target plant population. Most corn plants at 28,000–34,000 seeds/acre. Bags needed = (acres × seeds/acre) ÷ seeds per bag. Standard corn bags contain 80,000 seeds — one bag plants approximately 2.5–2.9 acres.

Pacific Northwest winter wheat: 60–100 lbs/acre depending on variety, planting date, and seedbed conditions. Earlier planting (before October 1): 60–75 lbs/acre. Late planting after October 15: 90–110 lbs/acre.

Seed pieces/acre = 43,560 ÷ (row spacing ft × in-row spacing ft). At 36-inch rows and 9-inch in-row spacing: 43,560 ÷ (3 × 0.75) = 19,360 pieces/acre. At 2 oz average piece weight: 19,360 × 0.125 lbs = 2,420 lbs/acre seed.

Optimal Russet Burbank seed piece: 2.0–2.5 oz (57–71 g) with at least 2 eyes. Pieces below 1.5 oz increase disease risk; above 3 oz offer diminishing returns. Blocking to uniform size reduces variability in emergence and plant spacing.

Adjusted seeding rate = target plants/acre ÷ germination fraction. At 94% germination targeting 30,000 plants/acre: 30,000 ÷ 0.94 = 31,915 seeds/acre needed. The calculator includes a germination percentage adjustment.

Russet Burbank: 9–10 inches. Clearwater Russet: 10–12 inches (wider for better size profile). Ranger Russet: 9–10 inches. Umatilla Russet: 9–10 inches. Russet Norkotah: 10–12 inches. Mountain Gem Russet: 10–12 inches. All at standard 36-inch rows.

Seeds per acre = (lbs/acre seed rate × seeds/lb). For corn at 34,000 plants/acre with 94% germination, you need 34,000 ÷ 0.94 = 36,170 seeds/acre. At 80,000 seeds/unit, that is 36,170 ÷ 80,000 = 0.452 units/acre. The seed rate calculator handles this conversion automatically for corn, soybeans, wheat, and other crops.

Corn seeding rates in the Columbia Basin and Pacific Northwest typically run 30,000–36,000 seeds/acre for dryland and 32,000–38,000 seeds/acre for irrigated production, adjusted for hybrid, soil, and irrigation capability. Higher plant populations (38,000+) are sometimes used on high-yield irrigated ground but require careful hybrid selection to avoid barrenness and stalk rot.