Overseed & Mix-Ratio Calculator
Work out how much clover or fescue to oversow into an existing lawn — at a light, standard, or heavy rate.
What this does
Enter your existing lawn area, choose a target species, and pick a density. The calculator returns the pounds of seed to oversow and the matching product, using rates tuned for topping up living turf rather than starting from bare soil.
Lighter rates for living turf
density: light = low end · standard = mid · heavy = high end of range
Overseeding rates are deliberately lighter than new-lawn rates — you’re filling gaps in living turf, not building a stand from scratch.
Sourced overseed rates: white clover 0.25–0.5 lb per 1,000 sq ft, fine fescue 2–3 lb, tall fescue 6–8 lb. ‘Standard’ density uses the middle of each range.
Worked example: topping 5,000 sq ft of tired lawn with clover at the standard 0.35 lb per 1,000 needs about 1.75 lb of seed.
Method & data pinned to: Seeding-rate library (extension-sourced) — v2026-06.
Run the numbers
The interactive Overseed Calculator loads here.
Until then, the formula above gives the same result by hand.
Step by step
- 1. Enter your existing lawn area.
- 2. Choose the species you want to introduce or thicken.
- 3. Pick a density: light, standard, or heavy.
- 4. Read the pounds needed and the recommended product.
- 5. Mow low, rake for seed-to-soil contact, then sow.
Getting an accurate answer
Overseed in early fall or spring into thin or patchy turf, when soil temperatures suit germination and competition from existing grass is lowest.
Good seed-to-soil contact matters more than quantity — rake or core first so seed reaches the soil, not the thatch.
Data source & assumptions
Pinned to Seeding-rate library (extension-sourced) (v2026-06). Assumptions:
- Rates from extension overseeding guidance.
- Density maps to the low/mid/high of each range.
- Assumes existing turf, not bare soil.
- Excludes site prep (mowing, raking, coring).
Common questions
When is the best time to overseed?
Early fall is ideal in most regions; spring is the second choice. Both give seed warm soil and moisture without peak summer stress.
Light, standard, or heavy?
Light freshens a decent lawn, standard fixes general thinning, and heavy is for visibly patchy turf. When in doubt, choose standard.
What rate for clover into grass?
About 0.25–0.5 lb per 1,000 sq ft — a little goes a long way because clover spreads once established.
Do I need to till first?
No — overseeding works into existing turf. Just mow low and rake or core so the seed reaches soil.
Keep planning
A single species is an ingredient. The blend is the answer.
Bare Spot Overseed Repair Mix — fine fescue + white clover. Bare patches and overseeding. Buy the blend when the job needs more than one plant — the grass carries the wear, the clover feeds it, the flowers feed the bees. Buy the single species when you want one plant, one look, one job.