Why You Should Not Fertilize Kentucky Bluegrass in Summer

The Rule

Cool-season grasses (Kentucky bluegrass, fescue, perennial ryegrass) should be fertilized in late spring, early fall, and late fall. Never in hot summer months.

Why "Summer Guard" Products Are Misleading

Scotts and others market summer fertilizers as "safe," but safe ≠ beneficial. Summer fertilization forces top growth when roots are heat-stressed, depletes reserves, and increases disease susceptibility.

What Actually Helps in Summer

• Mow high (3–4 inches) regularly.
• Water deeply and infrequently (1 inch per week).
• Leave clippings to recycle nutrients.
• Spot-treat weeds manually.

Show This to Your Wife

Expert consensus: Summer fertilization of cool-season lawns is counterproductive. Save money and labor by following the science.