Lime calculator
Enter your area, your current soil pH, the pH you want, and your soil type. You'll get an estimate of the ground limestone to apply.
- Per 1,000 sq ft (lb)
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- Bags
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- Applications on a lawn
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A rough estimate for ground limestone. A soil test recommendation is more accurate.
Start with a soil test
Lime only helps soil that is too acidic, and adding it to soil that doesn't need it can cause problems. A soil test from your local extension service or a garden center kit tells you your current pH. Many lab reports include an exact lime recommendation, which beats any general estimate.
How the math works
As a rough guide, raising pH by one full point takes about 25 pounds of ground limestone per 1,000 square feet in sandy soil, 50 pounds in loam and 70 pounds in clay. Raising a 5,000 square foot loam lawn from 5.8 to 6.5 takes about 35 pounds per 1,000 square feet, or 175 pounds in total.
Target pH for common plants
| Plants | Preferred pH |
|---|---|
| Most lawns | 6.0–7.0 |
| Most vegetables | 6.0–7.0 |
| Blueberries, azaleas, rhododendrons | 4.5–5.5 (don't lime) |
Common questions
Why split the lime into several applications?
On established lawns, more than about 50 pounds per 1,000 square feet at once can sit on the surface and burn grass. Larger amounts are spread over two or more applications a few months apart.
How fast does lime work?
Slowly. Ground limestone takes several months to change soil pH, which is why fall is a popular time to apply it. Pelletized lime spreads more easily but works the same way.
What if my pH is too high?
Lime raises pH. To lower it, gardeners use elemental sulfur instead, again guided by a soil test.
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