How to test and amend lawn soil?

When applying lime to correct acidic soil, never exceed 50 lbs of ground limestone per 1,000 sq ft in a single application on an established lawn. If your soil test recommends more, split it into multiple applications spaced 3-6 months apart.

If your soil is compacted (screwdriver test fails at 4-6 inches), schedule core aeration for early fall (September for cool-season grasses) rather than spring. If aeration is critical, spring is acceptable but fall is preferred.

Apply liquid sea kelp extract at the label rate (typically 1-3 oz per 1,000 sq ft) every 2-4 weeks starting in late spring. It can be tank-mixed with humic acid for a combined application.

Apply a liquid humic acid product at the label rate (typically 3 oz per 1,000 sq ft) every 2-4 weeks during the growing season using a hose-end or backpack sprayer.

Check the organic matter (OM) percentage on your soil test report. Healthy lawn soils should have at least 2% OM, with 3-5% being the optimal range. If below 2%, prioritize compost topdressing and mulching clippings.

After core aerating (ideally in fall, but spring works too), spread a quarter-inch layer of finely screened compost over the lawn and rake or drag it into the aeration holes. One cubic yard covers approximately 1,000 sq ft at this depth.

If your soil test shows pH above 7.5, apply elemental sulfur at no more than 5 lbs per 1,000 sq ft on established lawns. Apply in spring when soil microbes are active and can convert sulfur to sulfuric acid.

If your soil test shows pH below 6.0, apply pelletized limestone at the rate recommended by the test report. Apply in spring or fall, ideally after core aeration, and water in lightly.

Establish a routine of testing your soil every 3 years. Test more frequently (annually) if you are actively correcting pH or building organic matter, or if your lawn has persistent problems.

A professional soil test ($15-30) measures pH, phosphorus, potassium, magnesium, calcium, and organic matter. The report includes specific lime and fertilizer recommendations for your soil. Virginia Tech says it plainly: don't guess — soil test. It is the single best investment in lawn care.