Pounds of seed, starter fertilizer, and supplies — for new lawns, overseeding, or bare patch repair.
Based on the dimensions on the left — edit them to match your project and this updates as you type.
10 lbs needed · 2 × 7-lb bags
Tip: Rake soil to ¼" depth before seeding. Seed-to-soil contact is the #1 factor in germination.
1 bag — feeds seedlings for the first 6 weeks
Tip: Never use standard lawn fertilizer on new seed — high nitrogen burns seedlings. Use starter formula only.
Locks in moisture and protects seed from washing away — especially on slopes
Tip: Apply a thin, even layer — just enough to see 50% of the soil through it. Too thick and seed can't emerge.
For breaking up soil crust, working seed into the surface, and leveling topdressing
New seed needs light watering twice daily for 2–3 weeks. Covers 3,000–4,000 sq ft.
Tip: Water lightly and frequently until germination — keep the top ½" moist, not soggy.
This calculator works from 5 lb per 1,000 sq ft for a new lawn, which is a sensible middle for the sun-and-shade mixes most bags contain. Sow a single species and that number can be badly wrong in either direction. Published seeding rates run roughly:
The spread is seed size, not quality. A pound of Kentucky bluegrass holds roughly two million seeds; a pound of tall fescue closer to 230,000. You need about eight times the weight of tall fescue to put the same number of seeds on the ground. Check the rate printed on the bag against what this page gives you — if you are buying a pure tall fescue, expect to need more.
For cool-season grasses — bluegrass, the fescues, ryegrass — late summer into early autumn is the window worth waiting for. Soil is still warm enough to germinate quickly, air temperature is falling rather than climbing, and the annual weeds are finishing their year instead of starting it. A seeding that would struggle in June often establishes without drama in September.
Spring is the second-best option and a harder one. Crabgrass germinates in the same conditions your seed does, and the pre-emergent that would normally stop it will stop your grass seed too — so a spring seeding means going into summer with weed pressure and a root system that has not had time to go deep.
Warm-season grasses run on the opposite schedule. Bermuda and zoysia go down in late spring or early summer, once soil temperatures are reliably warm, and seeding them in autumn wastes the bag.
Before germination the job is to keep the top quarter inch of soil damp — not wet, and never dry. In warm weather that usually means two or three short waterings a day rather than one long one. The common mistake is a single deep soak, which washes seed into low spots, leaves bare patches where it came from, and lets the surface dry out for twenty hours in between. Seed that has taken up water and then dries out does not recover.
Once the grass is up, reverse it: fewer waterings, each one longer, so the moisture goes deeper and the roots follow it down. And expect the lawn to come up in waves. Perennial ryegrass shows in about 5 to 10 days, tall fescue 7 to 12, fine fescue 7 to 14, and Kentucky bluegrass anywhere from 14 to 30. Most bagged mixes contain ryegrass precisely so something green appears while the slow half is still working — which is also why a seeding that looks like a failure on day ten often is not.
Starter formulas carry proportionally more phosphorus — the middle number on the bag — because phosphorus supports root development in seedlings. Standard lawn fertilizer is the wrong product here: its nitrogen drives top growth that a seedling has no root system to support, and at high rates it will burn new grass outright.
One practical catch. Several US states restrict the sale or application of phosphorus lawn fertilizer, generally with an exemption for establishing new turf or where a soil test shows a deficiency. New seeding is usually the case the exemption was written for, but the rule and the paperwork vary by state, so check yours before ordering rather than after.
Using this page's rates — 5 lb per 1,000 sq ft for a new lawn, 3 for overseeding — and the common 7 lb bag. Every figure is this page's own formula applied to the stated area.
Measure the lawn in square feet, divide by 1,000, and multiply by the seeding rate. This calculator uses 5 lb per 1,000 sq ft for a new lawn, 3 for overseeding and 4 for bare patches, so a 2,000 sq ft lawn from scratch needs 10 lb — two of the common 7 lb bags. Those rates suit a typical sun-and-shade mix; a pure stand of one species can need anywhere from 2 to 10 lb, which is worth checking on the bag before you buy.
It depends on the species, and the spread is wide. Published seeding rates run roughly 2 to 3 lb per 1,000 sq ft for Kentucky bluegrass, 4 to 5 for fine fescue, 6 to 9 for perennial ryegrass, and 6 to 10 for tall fescue. The reason is seed size: a pound of Kentucky bluegrass holds around two million seeds, a pound of tall fescue closer to 230,000. You need roughly eight times the weight of tall fescue to put down the same number of seeds.
Around half to two-thirds of a new-lawn rate, because you are thickening existing turf rather than covering bare ground. This calculator uses 3 lb per 1,000 sq ft against 5 for a new lawn. Mow short — around 2 inches — and dethatch first if the thatch layer is over half an inch, or most of the seed never reaches soil and never germinates.
For cool-season grasses — bluegrass, fescue, ryegrass — late summer into early autumn is the best window by a wide margin. The soil is still warm enough for fast germination, the air is cooling, and annual weeds are finishing rather than starting. Spring is the second-best option and a harder one, because crabgrass germinates alongside your seed and you cannot use a pre-emergent herbicide without killing the grass seed too. Warm-season grasses like Bermuda and zoysia go in late spring to early summer, once soil temperatures are reliably warm.
Perennial ryegrass is the quickest at roughly 5 to 10 days, tall fescue 7 to 12, fine fescue 7 to 14, and Kentucky bluegrass the slowest at 14 to 30. That range is why most bagged mixes include ryegrass — it greens up fast and holds the soil while the bluegrass takes its time. It is also why people conclude a seeding has failed at day ten when the slow half has not started yet.
Light and frequent until it germinates, then less often and deeper. The goal before germination is to keep the top quarter inch of soil consistently damp, which in warm weather usually means two or three short waterings a day rather than one long one. A single deep soak washes seed into low spots and lets the surface dry out in between, and dry seed that has already started to swell will die. Once the grass is up, taper to fewer, longer waterings so the roots chase the moisture downward.
It helps, and the type matters. Starter formulas carry more phosphorus — the middle number — which supports root development in seedlings. Do not substitute standard lawn fertilizer: the high nitrogen in it pushes top growth the seedlings cannot support and can burn them outright. One caution on availability: several US states restrict phosphorus lawn fertilizer, usually with an exemption for new seeding or a soil test showing a deficiency, so check your state's rule before ordering.
Written and maintained by the BuildGuiders team. Seeding rates, germination windows and watering guidance follow published agronomic practice; the rate on your seed bag is specific to that blend and takes precedence over any general figure here. Product recommendations are researched and compared against manufacturer specifications and verified buyer feedback — we do not grow test plots.