How to use this lawn lime calculator
- Test your soil pH (a lab test also tells you the exact lime requirement).
- Enter current and target pH (6.0–7.0 suits most lawns).
- Choose your soil type.
- Apply with a spreader, preferably in fall, and water in.
Example
Raising a 2,000 sq ft loam lawn from pH 5.8 to 6.5 takes about 70 lb of ground limestone, or 2 bags of 40 lb.
What to know before you buy
Why soil pH matters
Most lawn grasses grow best at a pH of 6.0–7.0. In acidic soils, nutrients such as nitrogen, phosphorus and potassium become less available, so grass stays thin even with fertilizer.
Types of lime
Calcitic lime supplies calcium; dolomitic lime supplies calcium and magnesium. Pelletized lime is powdered limestone formed into pellets for easy spreading. Fast-acting lime products work quicker but at lower rates and shorter duration.
Lime per 1,000 sq ft to raise pH by 1 point
| Soil type | Ground limestone |
|---|---|
| Sandy | 25 lb |
| Loam | 50 lb |
| Clay | 70 lb |
Formula
Lime (lb) = area ÷ 1,000 × rate per pH point × pH increase. Typical rates for ground limestone: 25 (sandy), 50 (loam), 70 (clay) lb per 1,000 sq ft per point. These are general estimates.
Tips from the pros
- Pelletized lime spreads more evenly with a standard spreader than powdered lime.
- Dolomitic lime also adds magnesium; use it only if your soil test shows low magnesium.
- Retest the soil a year after liming.
Common mistakes to avoid
- Liming without a soil test: many lawns do not need it.
- Applying lime and fertilizer high in ammonium at the same time.
Frequently asked questions
How long does lime take to work?
Several months. Ground limestone reacts slowly, so apply it well before the growing season.
Can I apply too much lime?
Yes. Raising pH too high locks up nutrients like iron. Always base large applications on a soil test.
How much lime per acre?
Commonly 1–2 tons per acre for moderate pH correction, but base it on a soil test.
When is the best time to lime a lawn?
Fall or early spring, so rain and freeze-thaw cycles work the lime into the soil.