Work out how much grass seed to buy, the best window to sow it, how long it takes to come up, and exactly how to water it in until it is established.
About this tool: how much grass seed do you need? Guide: seeding and overseeding a lawnLawn Seeding Steps
Rake the soil loose and level, and pick out stones and roots, so every seed lands on bare soil.
Spread 2.5 lb of seed in two passes: half walking one way, half across it, so no strip is missed.
Rake lightly so seed is just covered, then firm it with a roller or your feet. A thin compost topdress helps hold moisture.
A starter fertilizer at sowing, about 3.8 lb of nitrogen for this area, helps most where a soil test shows phosphorus is low.
Two to three short waterings a day until it's up, about 6 to 12 days. Wait until after the third mow for weed killers, and check a pre-emergent's label, since some need longer.
Related Tools
How much nitrogen your grass needs over a year, split into feedings that land in the 0.5 to 1.0 lb window, in pounds of the bag you own.
Open the calculatorInches a week for your grass, season and soil, turned into days a week, minutes per zone, and cycle-and-soak splits that stop runoff.
Open the calculatorWhether the lawn needs lime at all, and how many bags of which kind if it does, worked out without a soil test.
Open the calculatorWhen to apply crabgrass pre-emergent, and when billbugs and Japanese beetles appear, based on this year's heat.
Open the calculatorSeed size varies by an order of magnitude, so rates do too. Pounds per 1,000 sq ft:
| Grass | New lawn | Overseeding |
|---|---|---|
| Kentucky bluegrass | 2 lb | 1 lb |
| Perennial ryegrass | 6 lb | 4 lb |
| Tall fescue | 7 lb | 3.5 lb |
| Fine fescue | 4 lb | 2 lb |
| Bermuda / couch (hulled) | 1 lb | 0.5 lb |
| Zoysia | 1.5 lb | 1 lb |
| Centipede | 0.5 lb | 0.3 lb |
| Buffalograss | 2 lb | 1.5 lb |
| Bentgrass | 1 lb | 0.5 lb |
| Kikuyu | 1 lb | 0.5 lb |
| Seashore paspalum | 1.5 lb | 1 lb |
Per 1,000 sq ft; 1 lb per 1,000 sq ft is about 5 g/m² (sources). Double the bermuda rate for unhulled seed. More is not better: sown thick, seedlings compete and you get a weak mat that thins out anyway.
Cool-season: late summer into early autumn, by a wide margin. Warm-season: late spring once soil is reliably 65 to 70 °F (18 to 21 °C). Soil temperature beats the calendar, so buy a thermometer.
Seed on thatch does not germinate. Mow short, rake to expose soil, cover to a quarter inch (6 mm). Below half an inch (13 mm) most never surfaces.
Light and frequent, keeping the top inch damp, often twice a day. A seed that germinates then dries is dead. Taper to deep and infrequent after a few mows. Bluegrass can take 30 days, so do not reseed bare patches too early.
Most pre-emergents stop grass seed as effectively as weed seed. Siduron and mesotrione are the exceptions, but the label governs.