Why Is My Lawn Turning Brown in Summer? (Pacific Northwest Guide)

Every summer, it happens across the Pacific Northwest.

A lawn that looked lush and green in May suddenly turns patchy, dry, or completely brown by August. It's easy to assume the grass has died—but in many cases, it's simply taking a summer nap.

If you live in western Washington or western Oregon, there's a good chance your lawn is made up of cool-season grasses such as perennial ryegrass, tall fescue, or Kentucky bluegrass. These grasses naturally slow down or go dormant during prolonged heat and dry weather to conserve energy.

The good news? A brown lawn isn't always a dead lawn.

Why lawns turn brown

1. Summer dormancy (most common)

During extended hot, dry weather, cool-season grasses reduce growth and allow their blades to turn brown while keeping the crown and roots alive.

This is completely normal.

Once autumn rain returns, most healthy lawns green up again within a couple of weeks.

2. Not enough water

If drought continues for many weeks, grass may begin to suffer.

Signs include:

• footprints remain visible

• curled leaf blades

• brittle grass

• soil pulling away from edges

Deep watering once or twice a week is far better than daily sprinkling.

3. Mowing too short

Cutting grass too low removes the leaf area that shades the soil.

This causes:

• faster evaporation

• hotter soil

• shallower roots

• increased drought stress

Raise your mower during summer.

4. Dog urine

Small circular patches with dark green edges usually point to dog damage rather than drought.

5. Lawn diseases

Although less common during dry weather, fungal diseases can also create brown patches.

If the patches spread rapidly or show rings or unusual discoloration, investigate further.

Dormant or dead?

Should you water?

You have two options.

Let it go dormant

Perfectly acceptable.

Provide around ½–1 inch of water every 3–4 weeks to keep the crowns alive during extended dry spells.

Keep it green

Water deeply once or twice a week.

Aim for about 1 inch of water per week, including rainfall.

Avoid light daily watering.

Should you fertilize?

No.

Avoid fertilizing during hot weather.

The best time to fertilize lawns in the Pacific Northwest is early autumn when cooler temperatures return and grass begins actively growing again.

Should you mow?

Yes—but mow high.

Recommended mowing heights:

• Tall fescue:

  3–4 inches

• Perennial ryegrass:

  2.5–3.5 inches

• Kentucky bluegrass:

  2.5–3 inches

Never remove more than one-third of the blade at a time.

Five things to do in August

• Raise your mower.

• Water deeply if keeping the lawn green.

• Leave clippings on the lawn.

• Avoid fertilizing.

• Plan overseeding for September.

When will it recover?

For most western Washington and western Oregon lawns, recovery begins with the first consistent autumn rain, usually during September or October.

As temperatures cool and soil moisture returns, dormant lawns often green up surprisingly quickly.