Summer Dormancy in Tall Fescue: What to Do (and Not Do) During Heat Waves

Understanding the Problem

A Los Banos, California homeowner sees their 3-year-old 'Medallion' tall fescue turning brown in 100°F+ temperatures. They were advised to dethatch, apply a liquid soil penetrant, and use Scotts SummerGuard.

Correct Approach

Tall fescue is a cool-season grass that enters summer dormancy to survive extreme heat. The brown color is protective, not dead.

• Do NOT dethatch, aerate, or renovate now. Wait until temperatures drop below 85°F in fall.
• Do NOT fertilize in summer. Fertilize only in spring and fall when night temps are below 65°F and day temps 70–85°F.
• Minimize traffic. Avoid walking on dormant turf.

Long-Term Options

If summer dormancy is unacceptable, consider converting to warm-season grasses like Bermuda, St. Augustine, or Bahia, which stay green in heat but go dormant in winter. These grasses are fertilized during their active summer growth.