Interpreting a Soil Test for a New Acidic Lawn: Lime, Corn Gluten, and Fall Seeding

Critical Numbers

• pH 4.4: Extremely acidic—nothing absorbs nutrients at this level. #1 priority.
• Phosphorus 225 (Very High): Inhibits other nutrient uptake. No P fertilizer needed.
• Calcium 790 (Very Low): Needs lime (supplies Ca + Mg).
• Organic Matter 1.1%: Low—build gradually.
• CEC 15.5, Base Saturation: H 62.3%: Confirms acidity dominance.

Action Plan

1. Lime immediately: Pelletized or dolomitic lime (supplies Ca & Mg). Lab says 200 lbs/1,000 sq ft at 50 lbs every 4–6 months. Never mix with nitrogen fertilizer.
2. Corn gluten meal (Renaissance 10-0-0): Apply at forsythia bloom. Provides slow-release N + weed prevention. Do not overseed for 4–6 weeks (7–8 weeks safer).
3. Organic potash (0-0-30): Apply this spring for fall root development.
4. Cover crop after CGM: Clover/alfalfa to fix N, aerate clay, suppress weeds.
5. Overseed Sept–Oct: Bluegrass or bentgrass (if mowing every 3 days). Mow high, leave clippings.
6. Water CGM: Moisten to stick—don't dissolve. Prevents wind loss.

Phosphorus Mystery

One fertilizer application shouldn't yield 225 ppm. Possible sampling error or prior heavy manure use. Excess P locks up other nutrients—lime and organic matter will help rebalance.