Cool-Season Lawn Care in Portland: Fertilization Schedule and Clover Control

Identifying Your Grass Type

In Portland, typical cool-season grasses include fine fescues, perennial ryegrass, Kentucky bluegrass, and tall fescue. All thrive with similar care.

Optimal Fertilization Timeline

• Late Spring (May): Light application to green up for summer.
• Early Fall (September): Major feeding to build root reserves.
• Late Fall (November): Final application to store energy for winter.

Avoid summer fertilization—cool-season grasses go dormant in heat, and feeding then depletes stored energy.

Fertilizer Selection

Choose a high-nitrogen formula labeled for lawns (e.g., Scott's Turf Builder 29-3-4). Apply to dry grass, then water in immediately.

Controlling Clover

Option 1: Weed-and-Feed Granules

Use a product with broadleaf weed control (not crabgrass preventer). Apply to a wet lawn so granules adhere to clover leaves. Wait 48 hours before watering. Best done in early fall when temperatures drop below 85°F.

Option 2: Spot-Spray Herbicide

Spray Ortho Weed-B-Gon or similar clover-labeled product directly on patches. Same temperature restriction applies. Avoid non-selective herbicides like Roundup—they kill grass too.

Key Reminders

• Never fertilize in summer.
• Herbicides only in spring or fall below 85°F.
• Mow high (3 inches) year-round.