Late Summer Lawn Rescue: Treating Grubs and Repairing Grub Damage

If your lawn is starting to look patchy, spongy, or brown in late summer, you might be dealing with one of turf's most destructive pests: grubs.

Grubs are the larvae of beetles—usually Japanese beetles, June bugs, or European chafers. These plump, white, C-shaped larvae feed on grass roots, often unnoticed until the damage becomes severe. Late summer through early fall is the best time for DIY lawn warriors to take action. Here's how to spot, treat, and repair grub damage before winter sets in.

Not all brown spots are caused by grubs. Here’s how to tell:

• Spongy Turf: Affected areas feel soft underfoot, almost like new carpet padding.

• Peeling Grass: If the roots are eaten, the grass can be rolled back like a carpet.

• Animal Activity: Raccoons, skunks, and birds may dig up your lawn overnight to feast on grubs.

• Soapy Water Test: Armyworms can be dected by watching the lawn after pouring some soapy water (dish soap) onto the brown spots in the lawn. Armyworms will rise to the surface of the lawn in about 1 minute if you have armyworms.

Best Time to Treat: Late Summer to Early Fall

This is when grubs are small and closest to the surface, making treatment most effective.

Treatment Options:

Curative Treatment:
Use DuoCide® if grubs are already active. DuoCide works quickly but doesn’t prevent future outbreaks.

Preventative Treatment:
While preventative products like GrubOut Plus Lawn Food 17-0-3 are best applied in late spring, it's still worth applying if you're seeing early-stage grub activity in late summer.

Pro Tip: Water your lawn after treatment to help products penetrate the soil and reach the grubs.

Once the grubs are treated, you’re left with the damage. Here’s how to get your lawn bouncing back:

1. Rake and Remove Dead Grass

Gently rake away dead patches to expose the soil beneath.

2. Loosen the Soil

Use a garden rake or cultivator to break up compacted areas. This makes it easier for new grass seed to take hold.

3. Reseed the Lawn

• Choose a grass seed blend that matches your existing lawn. Consider The Andersons seed options. Click to learn more about choosing the right seed for your lawn.

• Apply evenly over the bare spots.

• Lightly rake the seed into the top ¼ inch of soil.

4. Fertilize

Use a starter fertilizer, like New Lawn Starter 20-27-5 or EcoFusion™ Starter 16-21-4, to encourage strong root growth. Avoid high-nitrogen fertilizers until the new grass is established.

5. Water Consistently

Water daily (or as needed) to keep the soil moist until the new grass is at least 2 inches tall. After that, reduce to deeper, less frequent watering to encourage root depth.

• Healthy lawns resist pests better. Mow high, water deeply, and avoid over-fertilizing.

• Dethatch in spring to reduce places beetles like to lay eggs.

• Apply preventative grub control in late spring or early summer if you’ve had recurring issues.

Grubs can be a lawn’s worst enemy, but with the right approach, you can stop them in their tracks and repair the damage before fall. By acting in late summer or early fall, DIYers give their lawns the best shot at bouncing back strong before winter—and looking lush and green next spring.