How Much Lime to Put on a Lawn? Per Square Foot, Bags and Fall Timing

Say a 40 lb bag of lime is leaning against the garage wall, and the front lawn measures 50 by 60 feet. Don't open it yet: University of New Hampshire Extension says lime should not be applied unless a soil test shows it is needed, because too much can be as harmful as too little. When a test does call for lime, it gives pounds per 1,000 sq ft. A 50 lb rate works out to 0.05 lb, or 0.8 oz, per square foot. UNH says to split anything over 50 lb per 1,000 sq ft and to apply the rest 3 to 6 months later.

Quick pick: a mail-in soil test first, then a broadcast spreader set to spread the lime in two passes.

Free calculator: get seed and fertilizer by the 1,000 sq ft in our free lawn calculator.

How much lime: the math

Lime (lb) = lawn sq ft ÷ 1,000 × the rate on your soil test. Bags = lb ÷ bag weight, rounded up. Example lawn: 50 × 60 ft = 3,000 sq ft, 40 lb bags.

25 lb per 1,000 sq ft: 0.4 oz per sq ft. 75 lb total, 2 bags.

50 lb per 1,000 sq ft: 0.8 oz per sq ft. 150 lb total, 4 bags.

75 lb per 1,000 sq ft: split it. 150 lb now (4 bags), 75 lb in 3 to 6 months (2 bags).

100 lb per 1,000 sq ft: split it. 150 lb now, 150 lb in 3 to 6 months (4 bags each time).

In UNH's words, light rates 'disappear after one or two rains', so don't expect to see them.

Step 1: test the soil

Target: UNH puts the best pH for turf at 6.0 to 6.5.

Already above that: skip the lime. Clemson Extension says that above pH 6.5, phosphorus and most micronutrients become less available.

Where to test: your state Extension soil lab or a mail-in kit. UNH's soil testing program runs pH tests, and Clemson has a Lime Rate Calculator for its soil test results.

When: Clemson says to take soil samples in fall for the next year's garden.

Pelletized or ground lime?

Pelletized: UNH says it is finely ground lime pressed into pellets with a binder. It costs more, spreads more easily, cuts dust and breaks down with a soaking rain or watering.

Ground: UNH says its white color makes uneven spots easy to see.

Hydrated: Clemson says to use it with caution; it works faster than limestone.

Calcitic or dolomitic: UNH says calcitic lime supplies calcium and dolomitic supplies calcium and magnesium.

When to put lime on a lawn

UNH says fall is often recommended, so the lime can start raising pH over winter, but it can go down any time of year. Clemson says fall or winter.

☐ Rake the leaves off first. Clemson says lime needs as much contact with the soil as possible.

☐ Use a drop or rotary spreader (UNH).

☐ Spread half the lime in one direction and half crosswise, as UNH advises.

☐ Mark the calendar for any split application, 3 to 6 months out.

☐ Retest in a few years. UNH says liming to pH 6.5 should last at least 4 years.

UNH says each pound of nitrogen from urea or ammonium nitrate takes about 1¾ lb of lime to neutralize. See when to fertilize in fall.

Soil test kit and spreader (#ad)

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MySoil Soil Test Kit: a mail-in lab test of pH and nutrient levels, with what to apply and how much, per the maker. See it on Amazon

Scotts Turf Builder EdgeGuard DLX Broadcast Spreader: comes pre-calibrated, holds up to 15,000 sq ft of Scotts product, and has an edge shield to keep product off beds and pavement, per the maker. Scotts lists seed, fertilizer, salt and ice melt, not lime, so check your lime bag for a spreader setting. See it on Amazon

Comparing spreaders? See our small-lawn picks.

Lawn lime FAQ

How much lime per square foot?

Whatever your soil test says, divided by 1,000. At 50 lb per 1,000 sq ft, that is 0.05 lb, or 0.8 oz.

How much lime for a 1,000 sq ft lawn?

The soil test rate, up to 50 lb at one time (UNH). Split anything above that.

Should I lime my lawn in the fall?

Fall is often recommended so the lime works over winter, UNH says, though any time of year works.

Can you put down too much lime?

Yes. UNH says too much can cause trace element shortages.

No test?

UNH's rule of thumb for lawns not limed in years is 40 to 50 lb per 1,000 sq ft.

Watch Curb Calc on YouTube: youtube.com/@curbcalc

Sources: University of New Hampshire Cooperative Extension, Margaret Hagen, It's Always a Great Time to Lime; Clemson Cooperative Extension Home & Garden Information Center, How to Change Soil pH in South Carolina.