Free seed rate calculator. Determine bulk seeding rates with Pure Live Seed (PLS) for accurate crop establishment and efficient seed buying.
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Proper seeding rate is crucial for crop establishment and yield. Our calculator uses Pure Live Seed (PLS) methodology to account for germination and purity rates, helping you determine exactly how much seed to purchase for your field size while factoring in expected field losses.
Seeding rate calculations convert your target plant population into the bulk seed you actually need to buy. The key is Pure Live Seed (PLS) — germination × purity — which measures how much of a seed lot is genuinely viable and pure. Sizing seed on a PLS basis (the method printed on every seed-analysis tag and taught by USDA-NRCS and university extension services) ensures enough live seed reaches your target stand after normal field losses.
Bulk Seeding Rate Formula
Calculate corn, soybean, and wheat seeding rates for precision planters.
Determine alfalfa, clover, and grass seed rates for pasture and hay fields.
Calculate component rates when blending multiple cover crop species.
Know exactly how many bags to order for your acreage and avoid costly over-ordering.
Achieve target plant populations for maximum yield potential and crop performance.
Avoid over-seeding that wastes expensive seed or under-seeding that reduces yields.
Account for germination and purity rates to compensate for lower-quality seed lots.
PLS is the percentage of seed that is both pure (the intended species) and viable (capable of germinating). It's calculated as Germination% × Purity% ÷ 100. For example, seed with 90% germination and 98% purity has 88.2% PLS.
These values are on the seed analysis tag attached to every bag of certified seed. The tag shows test date, germination percentage, purity percentage, and other seed quality information.
Field survival accounts for seeds that germinate but don't survive to become established plants due to weather, pests, disease, or planting conditions. For good conditions, use 90-95%; for poor conditions, use 80-85%.
Different crops have different seed sizes (seeds per pound), target plant populations, and tolerance for crowding. Small grains may need millions of seeds per acre, while corn only needs 30,000-35,000 plants.