How to Overseed Your Lawn

Why overseed at all

Grass plants do not live forever. Over time a lawn thins out from heat, traffic, and age, and bare spots invite weeds. Overseeding drops fresh seed into the existing turf so new, young grass keeps the lawn thick and crowds weeds out. Done on a regular cycle, it is the cheapest way to keep a lawn looking full.

The manual way

1. Time it right. Cool-season grasses (fescue, bluegrass, ryegrass) overseed best in early fall, when soil is still warm but the air has cooled and weeds have slowed. Warm-season grasses (bermuda, zoysia) go in late spring to early summer. Your lawn care calendar will pin down the window for your grass.
2. Mow low and clear the surface. Drop your mower to about 1.5 to 2 inches and bag the clippings so seed can reach the dirt. Rake out dead grass and thatch.
3. Loosen the soil for seed-to-soil contact. Seed has to touch soil to sprout, not sit on top of thatch. Core aerate if you can, or scratch up the surface with a rake.
4. Calculate how much seed you need. Seed is rated in pounds per 1,000 sq ft: tall fescue runs about 5 to 8 lbs, Kentucky bluegrass 2 to 3 lbs, ryegrass 5 to 8 lbs. Multiply the rate by your lawn size and divide by 1,000 (how to measure your yard).
5. Spread it evenly. Use a broadcast or drop spreader and put down half walking one direction and half walking the other, so you do not leave stripes.
6. Water lightly and often. Keep the top inch of soil moist with short daily (or twice-daily) waterings until the seedlings come up, usually 1 to 3 weeks, then taper back to deep, infrequent watering.

The easy way with SimpleLawn

The fiddly parts of overseeding are the timing and the seed math. SimpleLawn handles both. Pick your grass type and spreader, enter your lawn size, and it returns the exact pounds of seed to buy plus the step-by-step. Already mapped your lawn? The size is filled in for you.

Try it now with the free seed and treatment calculator, no download needed.