Grass Seed Calculator: How Much Grass Seed Per Square Foot

The calculator uses pounds of seed = area in square feet / 1,000 x seeding rate, with the midpoint of the extension range for your grass type, or half of it for overseeding. Bags are rounded up. Coated seed products, such as bags with seed, fertilizer and a moisture coating, weigh more per square foot of coverage because much of the weight is coating, so for those products trust the coverage printed on the bag over a pounds-per-1,000 rate. The Scotts Turf Builder Grass Seed Tall Fescue Mix, 16 lb is labeled for 1,330 square feet new or 4,000 square feet overseeded, while the uncoated Pennington Kentucky 31 Tall Fescue Grass Seed, 40 lb covers up to 8,000 square feet.

More seed is not better. Sowing far above the recommended rate crowds seedlings, which then compete for water and light and become more prone to disease. Seed-to-soil contact matters more than the amount: rake it in lightly, roll it or tamp it, and keep the top half inch of soil consistently moist until the grass is mowed for the first time.

A new lawn starts from bare, prepared soil, so every plant must come from seed and you sow the full rate. Overseeding adds seed into an existing lawn to thicken thin areas or introduce better varieties, so roughly half the rate is enough. Overseeding works best after core aeration or dethatching, which opens the soil surface: see dethatcher vs aerator and how to overseed a lawn. Do not apply most pre-emergent crabgrass preventers before seeding, since they also stop grass seed from germinating; the label will list the waiting period.

Use a spreader rather than hand-throwing. Split the seed in half and make two passes at right angles, which evens out the pattern and avoids stripes. A handheld broadcast unit like the Scotts Whirl Hand-Powered Spreader works for patches, a push broadcast spreader such as the Scotts Turf Builder EdgeGuard DLX Broadcast Spreader covers lawns up to about a third of an acre, and a pneumatic-tire model like the EarthWay 2150 Commercial 50 lb Broadcast Spreader handles bumpy ground. For acreage, a tow-behind unit such as the Agri-Fab 130 lb Tow-Behind Broadcast Spreader behind a lawn tractor seeds half an acre per fill. Start with the spreader setting on the seed bag, and close the hopper at the end of every pass. Compare types in drop vs broadcast spreaders.

Match the seed to your climate and sun. For cool-season lawns in full sun to partial shade, a tall fescue blend like the Jonathan Green Black Beauty Tall Fescue Blend, 25 lb is the drought-tolerant workhorse; for partly shaded northern lawns, a sun and shade mix like the Pennington Smart Seed Sun and Shade Mix North, 20 lb; for fast fill and high traffic, the GreenView Pure Grass Seed Perennial Ryegrass Blend, 20 lb; and for a sod-quality bluegrass lawn with patience for slow germination, the Jonathan Green Blue Panther Kentucky Bluegrass Seed, 25 lb. In the South, the Scotts Turf Builder Grass Seed Bermudagrass, 4 lb suits full sun, while St. Augustine only establishes from plugs such as the SodPods St. Augustine Seville Grass Plugs, 64 Count. Tiered picks are in the best grass seed, and grass-by-grass details are in grass types.