Lawn Lime Calculator

Enter your soil test pH and lawn size — get the pelletized lime dose, split into safe applications.

Target for most grasses is 6.0–7.0.

Unsure? Use the lawn size calculator.

Lime needed
Per 1,000 sq ftSee on Amazon
Applications (max 50 lb/1,000 each)
In 40-lb bags

Estimates from standard extension tables — a lab soil test's own recommendation wins (it measures buffer pH, which this can't). Retest 6–12 months after liming.

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The lime math

dose ≈ 30 lbs per 1,000 sq ft per 0.5 pH point below 6.5
adjusted for soil texture · capped at 50 lbs/1,000 per application

pH is a log scale, so each half-point is a real chemistry lift, and clay soils buffer harder than sand (more lime to move the same amount). That's also why corrections cap per application: soil chemistry needs weeks to equilibrate, and overdosing overshoots into alkaline territory that's just as bad and harder to fix.

A worked example

A 5,000 sq ft loam lawn testing 5.8: about 42 lbs per 1,000 — 210 lbs total, so five to six 40-lb bags in ONE application this fall (it's under the 50 cap), retest in spring. The same lawn on clay at 5.4: ~86 lbs per 1,000 — that's two rounds, eight-plus weeks apart, not one heavy pass.

Why pH is worth fixing

Below 6.0, fertilizer efficiency drops hard — nutrients lock up chemically and the fertilizer you spread partly wastes. Moss creeping in, clover thriving, and grass sulking despite feeding are all classic acid-soil tells. Fix the pH first and every other input starts working at full strength.

Frequently asked questions

How much lime does my lawn need?

It depends on your soil's pH and how far it needs to move — typical corrections run 20–50 lbs of pelletized lime per 1,000 sq ft. The hard rule: never more than 50 lbs per 1,000 in one application; big corrections happen in rounds, 8+ weeks apart. Enter your pH above for the dose.

Do I actually need lime?

Only if a soil test says so. Lime raises pH — great on acidic soil (below ~6.0), pointless or harmful on neutral and alkaline soil. A $15 lab soil test (your state extension does them) or even a $10 probe beats guessing, because lime is nearly impossible to undo.

What kind of lime should I buy?

Pelletized calcitic lime for most lawns — dust-free, spreads through any broadcast spreader, acts in weeks. Dolomitic lime adds magnesium (choose it only if your soil test shows magnesium is low). Skip hydrated lime entirely: fast, caustic, and easy to burn a lawn with.

When should I apply lime?

Fall is best — winter's freeze-thaw works it into the soil, and pH is corrected by spring feeding season. Spring is fine too. Water it in after spreading, and don't apply the same week as fertilizer (lime can tie up nitrogen; give it 2+ weeks).

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