Lawn Lime Calculator

Calculate how much lime your lawn needs, based on area and soil type, so you buy the right number of bags.

Lime needed
22.5 kg
150 m² × 150 g/m²
Bags (25 kg)
1
Grams per m²
150 g/m²

How to use the lawn lime calculator

  1. Enter the lawn area in square meters.
  2. Choose soil type — clay soil is often more acidic and needs more lime than sandy soil.
  3. The calculator shows how much lime you need in total, and how many 25 kg bags to buy.

How the lime amount is calculated

The calculator multiplies the lawn area by the recommended lime amount per square meter for the selected soil type:

Lime (kg) = Area (m²) × Lime amount (g/m²) ÷ 1000

For a 150 m² lawn with normal soil (150 g/m²), you need 150 × 150 = 22,500 g, i.e. 22.5 kg of lime — equivalent to 1 bag of 25 kg.

Liming adjusts the soil's pH level, making nutrients more available to the grass and giving healthier, denser growth. Clay soil is often naturally more acidic than sandy soil, and therefore needs more lime to reach the same pH level.

Note: This is a general rule of thumb. For precise dosing, take a soil test and measure the actual pH. Liming is usually done in spring or fall, not during dry spells.

Frequently asked questions

When during the year should I lime my lawn?

Spring and fall are the best times for liming. Avoid liming during dry spells or right before heavy rain, since much of the lime can wash away before it has a chance to work.

Why does clay soil need more lime than sandy soil?

Clay soil often has a more acidic natural pH and greater buffering capacity, meaning more lime is required to noticeably raise the pH compared to lighter sandy soil.

Can I lime too much?

Yes. Too high a pH can make certain nutrients less available to the grass and favor weeds. Follow the recommended amount, and consider taking a soil test before liming repeatedly year after year.