DIY Calculator

Overseeding Calculator

Calculate seed needed to thicken an existing lawn without a full tear-out.

Why overseeding rates differ

  • Half the new-lawn rate

    Existing turf already covers the soil, so you only need enough seed to fill thin areas — not a full blanket.

  • Grass type

    Match your current lawn or choose a compatible blend. Rates vary widely between fescue, bluegrass, and warm-season grasses.

  • Prep matters

    Mow short, dethatch or aerate if needed, and rake seed into the top 1/4 inch of soil for the best germination.

  • Keep it moist

    Water lightly 1–2 times daily for the first 2–3 weeks so the seed bed stays damp but not flooded.

FAQ

How is overseeding different from a new lawn?
Overseeding uses roughly half the seed rate of a bare-ground seeding because you are filling in an existing lawn, not starting from scratch.
When is the best time to overseed?
For cool-season grasses, early fall is ideal. For warm-season lawns, late spring to early summer works best after soil warms up.