Garden Grass seed calculator
Seeding rates vary enormously by species — Kentucky bluegrass needs roughly a third of what tall fescue does for the same area, because the seed is far smaller and it spreads by rhizomes. Overseeding an existing lawn uses about half the new-lawn rate.
How this is calculated
Pounds of seed = (area ÷ 1,000) × the seeding rate for that species. Overseeding uses half the new-lawn rate.
Source: Seeding rates follow university extension guidance (Penn State Extension, Purdue Turf)
Worth knowing: Rates are for pure live seed on prepared soil. A seed blend or a coated seed will differ — check the bag, since coating can be 30-50% of the weight. More seed is not better: over-seeding produces thin, crowded seedlings that compete with each other and damp off.
Common questions
Is more seed better?
No. Seedlings sown too thickly compete with each other for light, water and nutrients, and the crowded, humid canopy invites damping-off disease. A stand sown at the correct rate fills in denser within a season than one sown at double rate.
When should I seed?
For cool-season grasses (bluegrass, fescues, ryegrass) late summer to early autumn is the best window — warm soil, cooling air, and far less weed competition than spring. Warm-season grasses (bermuda, zoysia) go in during late spring once soil is reliably warm.
Does coated seed change the amount?
Yes. Coating can be 30-50% of a bag by weight, so a bag of coated seed contains substantially less actual seed. Check the pure live seed percentage on the label and scale up accordingly.
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