How to Fix Soil pH

Never apply lime or sulfur without a soil test. Guessing at pH correction wastes money and can push pH in the wrong direction. A lab test ($15 to $30) tells you your current pH and the exact amount of lime or sulfur needed. The required amount depends on your soil type: clay soils need more product to change pH than sandy soils.

Most lawns east of the Mississippi have acidic soil below 6.0. Pelletized lime (calcium carbonate) is the standard correction. Apply 25 to 50 lbs per 1,000 sq ft based on your soil test recommendation. Spread with a broadcast spreader. Water in lightly. Lime works slowly: expect pH to rise over 3 to 6 months. Apply in fall or early spring for best results.

Common in the Great Plains and Southwest where soil pH exceeds 7.5. Elemental sulfur is the standard correction. Apply 5 to 10 lbs per 1,000 sq ft. Sulfur works even slower than lime: 6 to 12 months for measurable change. In heavily alkaline soils (pH 8.0+), full correction may be impractical. Choosing alkaline-tolerant grass varieties (bermuda, buffalo, bur oak) is often more effective than fighting the pH.

Fall (September to October) is ideal for lime applications because winter rain and freeze-thaw cycles work the product into the soil. Spring (March to April) is the backup. For sulfur, spring application works best because soil bacteria that convert sulfur to sulfuric acid are most active in warm, moist conditions. Do not apply sulfur during hot, dry summer months.

Wait 6 months after application, then retest. If pH hasn't reached the target, apply a second round at a reduced rate. Never exceed the soil test's recommended application rate in a single treatment because over-correction is worse than under-correction. pH swings stress plants. Gradual correction over 1 to 2 years is healthier than a single massive dose.