Interpreting Soil Test Results: Lime, Nutrients, and a Plan for Maryland Lawns

From Data to Action: Fixing Acidic, Nutrient-Poor Soil

A Maryland homeowner submitted detailed soil tests for front (pH 5.7) and back (pH 4.2) yards. Both are too acidic for most turfgrasses. Key findings:

• Front: Low K (0.9% vs 3–5%), low Mg (10.1% vs 12–15%), low Ca (53% vs 55–65%). Needs 1 ton lime/acre, 90 lbs N, 40 lbs P₂O₅, 80 lbs K₂O per acre.
• Back: Severely acidic (pH 4.2). Very low Ca (22%), high H (66.4%). Needs 3 tons lime/acre, plus Mg.

Priority: Lime, Lime, Lime

Pelletized lime (less dust) must be tilled in 2 inches—it's not water-soluble. Apply twice yearly; pH correction takes years. At pH <6.0, P, N, K, Ca, Mg are largely unavailable.

Grass Choice: Tall Fescue

Tall Fescue tolerates lower pH (down to 5.5) better than bluegrass. Overseed this fall. It's drought-tolerant, low-maintenance, and outcompetes weeds when mowed high.

Skip Chemical Fertilizers

Use compost, humus, and organic N sources (corn gluten meal, alfalfa meal). They feed soil microbes, which feed grass steadily. Avoid "weed and feed" and synthetic salts that damage soil biology.

Grub Note

Japanese beetle grubs = Milky Spore disease (a beneficial bacterium). Apply per label; it's safe for everything except grubs.