Grub Damage vs Drought Stress: How to Tell What's Killing Your Lawn
Table of Contents
- Why Is My Lawn Turning Brown?
- How to Tell If You Have Grubs in Your Lawn
- How Do You Get Grubs in Your Lawn?
- Lawn Drought Stress: What It Looks Like
- Grubs vs. Drought: Quick Glance Guide
- Fixing Drought or Grub Problems
- How Grub and Drought Damage Affect Cool-Season vs Warm-Season Grasses
- Grubs vs. Drought FAQs
When your lawn starts turning brown, it’s easy to panic. But before you start throwing down fertilizer or running the sprinklers 24/7, let’s get to the root of the problem. Is your grass just really thirsty, or could it be grubs munching on your lawn?
In this guide, we’ll show you how to tell if your lawn has grubs or drought stress. You’ll learn the clear signs, how to test for each issue, and most importantly, how to fix it.
TL;DR: If your grass lifts like a carpet and feels spongy, it’s probably grubs. If it’s crispy and doesn’t bounce back after stepping on it, it’s likely drought stress.
Why Is My Lawn Turning Brown?
Brown patches on your lawn are usually caused by one of two things:
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Grubs eating away at the roots beneath your turf
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Drought stress, where your grass isn’t getting enough water
Other culprits exist, but these two are at the top of the list, especially in summer. So, how can you tell which one is wrecking your yard?
Why Grubs Are a Problem for Your Lawn
Grubs are the larvae of beetles like Japanese beetles, June bugs, and chafer beetles. They feed on the roots of the grass, which prevents your lawn from absorbing water and nutrients. The result? A brown, thinning lawn that peels up like an old carpet.
For more info, meet the grubs that cause your lawn damage.
How to Tell If You Have Grubs in Your Lawn
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Spongy feel underfoot: A grub-infested lawn feels soft or bouncy when you walk on it.
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Peel test: Grab a handful of brown grass and gently pull. If it lifts easily, roots and all, and you see white C-shaped grubs underneath, bingo.
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Wildlife damage: Raccoons, skunks, and birds tearing up your yard may be hunting for juicy grubs.
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Irregular patches: Unlike drought, which often hits uniformly, grub damage usually appears in random spots.
Signs of Grub Damage on Your Lawn:
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Brown or wilting patches that worsen quickly
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Turf that pulls up easily
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Visible white grubs (especially in late summer and early fall).
Lawn Turning Brown but Not Dry?
If your lawn is turning brown but doesn’t feel dry, that’s a major clue pointing to grubs. Drought-damaged grass is typically dry, thin, and hard to the touch. If it’s brown and soft, check for grubs ASAP.
How Do You Get Grubs in Your Lawn?
Grubs start as beetles laying eggs in your lawn in midsummer. These adult beetles are attracted to healthy, moist lawns as ideal places to lay their eggs.
Once the eggs hatch — usually within a few weeks — the larvae begin feeding underground. These grubs feast on the roots of your grass for several weeks or months, depending on species and soil temperatures. During this time, your turf starts to weaken from below, showing patchy, irregular brown spots above.
You’re more likely to see damage if you’ve had beetle issues in past seasons, especially if your lawn wasn’t treated preventively. Even lawns that look great on the surface can hide a thriving grub population just beneath the topsoil.
Related: Grub Control: How to Get Rid of Grubs in Your Lawn
Lawn Drought Stress: What It Looks Like
Lawn drought damage occurs when grass lacks consistent moisture, especially during high temperatures or dry spells. Unlike grub damage, which tends to appear in isolated, irregular patches, drought stress usually presents as a more uniform discoloration across larger areas.
As the soil dries out, grass begins to shut down to conserve water. It curls, turns bluish-gray, then browns, and becomes crispy underfoot. If prolonged, drought can lead to root shrinkage, reduced growth, and, in severe cases, permanent turf loss.
Common Signs of Drought in Your Lawn:
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Footprinting: When footprints remain visible when you walk across the lawn, it’s a classic early sign of drought stress.
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Color shift: Grass turns from vibrant green to a dull, bluish hue before going brown.
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Patchy dormancy: Depending on sun and soil conditions, warm-season grasses may go dormant in some spots while others stay green.
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Soil resistance: Stick a screwdriver or moisture probe into the soil. If it’s difficult to push in, the soil is likely too dry.
Understanding drought stress is key to diagnosing problems and preventing long-term damage. A solid watering schedule, appropriate mowing height, and moisture-retentive products can help keep your lawn healthy during hot months.
Related: How to Build a Stress-Proof Lawn Before the Summer Heat Hits
Grubs vs. Drought: Quick Glance Guide
| Symptom | Grub Damage | Drought Stress |
|---|---|---|
| The turf feels spongy | ✅ Yes | ❌ No |
| Turf lifts up like carpet | ✅ Yes | ❌ No |
| Soil is hard and dry | ❌ No | ✅ Yes |
| Random brown patches | ✅ Often | ❌ Usually uniform |
| Wildlife digging up the lawn | ✅ Yes | ❌ No |
| Grass feels crispy/dry | ❌ No | ✅ Yes |
Fixing Drought or Grub Problems
Product Spotlight: What to Use and When
Choosing the right products at the right time can make all the difference. Depending on whether your lawn is battling grubs or drought stress, here's what we recommend.
→ For Grub Control
Acelepryn G Insecticide — This is your go-to curative treatment for active grub infestations. It’s a granular, season-long insecticide that targets not just grubs but also armyworms, cutworms, sod webworms, and other common lawn pests. Apply when you confirm grub activity using the tug test. Acelepryn G is low-risk for bees and other beneficial insects, making it a safe and effective option for residential lawns.
You can also get it in a liquid formula: Acelepryn SC Liquid Insecticide.
Caravan® G Insecticide and Fungicide — A dual-action granular product that combines the insect control of Meridian® 25WG and the disease control of Heritage® G fungicide. Caravan® G targets a broad spectrum of lawn pests, including white grubs, chinch bugs, sod webworms, and craneflies, while also preventing and controlling common turf diseases like brown patch, large patch, and fairy ring. Ideal for applications between May and July, a single treatment can provide season-long grub control and up to one month of preventive disease protection. Safe for all grass types and easy to apply with a broadcast spreader.
→ For Drought Recovery
Hydretain Moisture Manager — This is a game changer for dry lawns. Hydretain attracts moisture vapor from the soil and converts it into usable water for plant roots. It effectively reduces the need for frequent watering by improving water-use efficiency, which is especially helpful during drought conditions.
CarbonizPN-G™ — A granular soil amendment packed with biochar, humic acid, and composted poultry litter. It boosts soil structure, increases microbial activity, and helps retain moisture. Ideal for repairing drought-stressed areas and preparing the lawn for summer heat.
Mirimichi Green Release ZERO™ Liquid Biostimulant — This liquid biostimulant enhances nutrient availability and boosts uptake, providing organic compounds and minerals through the leaves and root system. Release ZERO™ mixes easily with fertilizer, herbicides, and pesticides to improve performance. It contains 10% liquid carbon for deeper roots and micronutrients that boost soil biology without adding nitrogen. Formulated to protect turf from heat and drought, it's safe for all grass types.
Use these products with a solid watering and mowing plan, and your lawn will recover faster and look better than ever.
Related: How Often Should I Water My Lawn?
How Grub and Drought Damage Affect Cool-Season vs Warm-Season Grasses
Different grass types respond differently to stress, and that includes both grub damage and drought conditions. Knowing whether you’re working with a cool-season or warm-season grass can help you interpret symptoms more accurately and choose the right treatment strategy.
Cool-Season Grasses (like Fescue, Kentucky Bluegrass, and Ryegrass)
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Grub damage: These grasses tend to have shallower root systems, which makes them more vulnerable to grub damage. Because they grow most actively in spring and fall, grub feeding in late summer can cause significant and sudden turf die-off.
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Drought stress: Cool-season grasses are less heat-tolerant and often enter dormancy in high summer. Drought stress can show quickly as uniform browning. These grasses may thin out or die back completely if not watered deeply.
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Recovery: These grasses respond well to fall overseeding and aeration. They're resilient with the right care but need protection during peak summer heat.
Warm-Season Grasses (like Bermuda, Zoysia, St Augustine, and Centipede)
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Grub damage: Warm-season grasses have deeper root systems and may initially mask grub damage better. However, damage becomes more apparent as feeding intensifies and large patches begin to detach from the soil.
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Drought stress: These grasses are more drought-tolerant and better adapted to heat. They may show patchy dormancy instead of full brownout. Inconsistent irrigation often leads to uneven coloring.
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Recovery: Warm-season grasses typically recover quickly with proper watering, soil improvement, and dethatching. Summer is their peak growing season, which helps speed up repair.
Understanding these seasonal and physiological differences is essential when diagnosing brown patches or planning recovery. When in doubt, match your lawn care plan to your grass type for the best results.
Related: How to Keep Your Lawn Green in the Summer Heat
Common Mistakes to Avoid When Diagnosing Lawn Problems
Even experienced lawn owners can get tripped up when trying to figure out what’s wrong with their turf. Avoiding these common mistakes can save you time, money, and a lot of frustration:
Mistaking Dormancy for Death
During drought or extreme heat, grass can go dormant and appear dead, but it might still be alive at the crown. Before ripping it out, perform a scratch test at the base of the blade—if it's green underneath, it's dormant, not dead.
Overwatering When It’s Grubs
If your lawn has grubs, no amount of watering will fix the problem. In fact, wet conditions can sometimes make the situation worse. Check for grubs before assuming your lawn is simply dry.
Not Checking Under the Turf
It’s easy to diagnose from the top, but the real answers are often under the surface. Always perform a tug test or gently peel back the turf to check for grub activity.
Skipping Follow-up Treatments
Whether you’re treating for pests or recovering from drought, your lawn needs time and support to bounce back. Follow up with proper watering, mowing, and feeding to ensure full recovery.
Treating the Whole Lawn Without Identifying the Problem
Blanket product applications without diagnosing the root issue can waste time and money. A targeted approach based on symptoms is more effective and healthier for your lawn.
Applying Fertilizer to a Stressed Lawn
Feeding a lawn suffering from drought or grub damage can backfire. Fertilizer can burn drought-stressed grass, and it won’t help if roots are missing. Focus on recovery first — fertilize later.
Grubs vs. Drought FAQs
Q: Can grub damage and drought stress happen at the same time?
A: Yes, they can overlap, especially in late summer. Drought weakens grass, making it more vulnerable to grubs, and grub damage can worsen the effects of drought. It's important to check for both.
Q: How many grubs per square foot is considered a problem?
A: If you find more than 5–10 grubs per square foot, that’s enough to cause visible lawn damage and should be treated right away.
Q: Should I fertilize a lawn that has grub or drought damage?
A: Not immediately. Wait until the issue is under control. For grub damage, treat the grubs first. For drought stress, rehydrate the lawn before applying any fertilizer.
Q: Can I prevent drought stress with soil amendments?
A: Yes. Products like soil surfactants or wetting agents help water penetrate compacted or hydrophobic soils, reducing the risk of drought stress.
Q: Can I seed or overseed a lawn that recently had grub damage?
A: Yes, but timing is key. After treating for grubs, wait a couple of weeks to ensure they’re gone, then overseed. Fall is ideal for cool-season grasses, while late spring to early summer works best for warm-season lawns.
Q: How often should I check for grubs during the season?
A: Start monitoring in mid-to-late summer, especially if you’ve seen beetles earlier in the season. If you notice brown patches or spongy turf, do a tug test in late July through September.
The Root of the Problem: Solved
Whether it’s a beetle baby buffet or a sun-scorched shutdown, your lawn is sending you signals — and now you know how to read them. Grub damage and drought stress may look similar on the surface, but understanding the subtle differences is what sets lawn pros apart from frustrated weekend warriors.
Remember:
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Spongy, peel-back turf? Likely grubs.
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Crispy, stubbornly dry grass? That’s probably drought.
The good news? Both problems are fixable, and you’ve got the tools, timing, and know-how to take action. So grab your screwdriver, do the tug test, and choose the right treatment.
Shop grub control and drought recovery products at the Golf Course Lawn Store. For more tips and tricks on how to keep your lawn looking immaculate, visit our YouTube channel.
Ron Henry
Ron Henry is the founder of Golf Course Lawn, which is dedicated to helping homeowners achieve golf course-quality lawns. He holds a certificate in Sports Turfgrass Management from the University of Georgia. With expert knowledge in turf care, fertilization, and weed control, he shares practical tips and product recommendations to create lush, healthy lawns.