Ground Limestone (Calcitic Lime)
37.5 lbs
Current pH
6.0
Target pH
6.5
Slightly Acidic
Moderate buffering. Most common garden soil type.
Standard depth is 6 inches. Deeper = more amendment needed.
| pH Range | Classification | Common Plants |
|---|---|---|
| 4.5–5.5 | Strongly Acidic | Blueberries, azaleas |
| 5.5–6.0 | Moderately Acidic | Potatoes, strawberries |
| 6.0–6.5 | Slightly Acidic | Most vegetables, roses |
| 6.5–7.0 | Neutral | Lawn grass, beans, corn |
| 7.0–7.5 | Slightly Alkaline | Lavender, asparagus |
| 7.5–8.0 | Moderately Alkaline | Few plants prefer this |
Inputs
Result
Loam soil needs 75 lbs per 1,000 sq ft per pH unit. pH change = 1.0 unit. Rate = 75 × 1.0 = 75 lbs/1,000 sq ft. For 500 sq ft: 75 × 0.5 = 37.5 lbs total. Split into 2 applications since 75 > 50 lbs/1,000 sq ft max.
Inputs
Result
Sandy soil needs 11 lbs sulfur per 1,000 sq ft per pH unit. pH change = 1.5 units. Rate = 11 × 1.5 = 16.5 lbs/1,000 sq ft. For 200 sq ft: 16.5 × 0.2 = 3.3 lbs total. Split into 4 applications (max 5 lbs/1,000 sq ft each).
Inputs
Result
Clay soil needs 135 lbs per 1,000 sq ft per pH unit. pH change = 0.7 units. Rate = 135 × 0.7 = 94.5 lbs/1,000 sq ft. For 5,000 sq ft: 94.5 × 5 = 472.5 lbs total. Split into 2 applications.
The most accurate method is a professional soil test through your local cooperative extension office ($10–$25). Home test kits cost $10–$15 and give approximate readings. Digital pH meters ($15–$40) offer quick readings but may be 0.5–1.0 off without calibration.
| Test Method | Cost | Accuracy | Turnaround |
|---|---|---|---|
| Extension lab | $10–$25 | ±0.1 pH | 1–2 weeks |
| Home kit (color) | $10–$15 | ±0.5 pH | Instant |
| Digital meter | $15–$40 | ±0.3–0.5 pH | Instant |
Most vegetables thrive between pH 6.0 and 7.0, with 6.5 being the sweet spot. At this range, essential nutrients like nitrogen, phosphorus, and potassium are most available. Some crops like potatoes prefer slightly acidic soil (5.5–6.0), while brassicas tolerate up to 7.5.
| Plant Group | pH Range | Ideal pH |
|---|---|---|
| Blueberries | 4.5–5.5 | 5.0 |
| Potatoes | 5.0–6.0 | 5.5 |
| Most vegetables | 6.0–7.0 | 6.5 |
| Lawn grass | 6.0–7.0 | 6.5 |
| Lavender | 6.5–7.5 | 7.0 |
It depends on soil type and how much you need to raise pH. Sandy soil needs 25–30 lbs of lime per 1,000 sq ft per pH unit. Loam needs 70–80 lbs. Clay soil needs 120–150 lbs. Never apply more than 50 lbs per 1,000 sq ft at once.
| Soil Type | Lime (lbs/1000 sq ft/pH unit) | Sulfur (lbs/1000 sq ft/pH unit) |
|---|---|---|
| Sandy | 25–30 | 10–12 |
| Loam | 70–80 | 20–25 |
| Clay | 120–150 | 45–60 |
Lime takes 2–3 months for initial changes and 6–12 months for full effect. Finely ground lime reacts faster than pelletized. Apply in fall for best results by spring planting. Always retest 3 months after application before adding more.
Soil type determines buffering capacity, which is the soil's resistance to pH change. Clay soils have high cation exchange capacity (CEC) with many charged particles, requiring 4–5 times more amendment than sandy soils. Sandy soils change easily but amendments leach out faster.
Vinegar provides a very temporary pH drop (hours) and can harm soil biology at high concentrations. Coffee grounds are nearly neutral (pH 6.5–6.8 after brewing) and do not significantly acidify soil. For meaningful pH changes, use lime or elemental sulfur.
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Last Updated: Mar 13, 2026
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