How to Know if Your Lawn Has Grubs and Prevent Infestation

Grubs can be one of the most frustrating lawn problems to deal with. They’re sneaky pests, hiding beneath the grass surface, causing significant damage before you even realize they're there. If you've noticed brown patches or birds digging through your yard, it might be time to check for grubs. Let’s explore how to recognize the signs of a grub infestation, why they’re so destructive, and steps to prevent them from taking over your lawn.

Recognizing Grub Damage: The Early Signs

Spotting grubs can be tricky, especially when the damage isn’t immediately obvious. Grubs are the larvae of beetles, like Japanese beetles and June bugs, and they live underground, munching on your grass roots. As they feed, they damage the roots, causing your grass to weaken and turn brown.

So, how can you tell if you have grubs? Here are some clear signs to look for:

Brown Patches That Lift Easily: 

Grubs chew through the roots, causing areas of grass to turn brown and die. Try lifting the brown patches. If they come up like a carpet, it’s a strong sign of grub activity.

Increased Animal Activity: 

Birds, skunks, raccoons, and even moles love grubs. If these animals are frequently digging around, they’re likely after something tasty—and grubs are a favorite.

Spongy Grass: 

Walk across your lawn, especially over the brown patches. If the ground feels soft or spongy, it’s because grubs have weakened the roots below.

If you’re seeing any of these signs, a lawn care expert can conduct a quick inspection to confirm if grubs are the cause. Catching them early can make all the difference in saving your lawn.

Check for Grubs Yourself with a Simple Test

Want to check for grubs without calling in help right away? It’s easy to do a little digging to see what’s going on beneath the surface. Choose an area near a brown patch, grab a small spade, and dig up about a square foot of turf to a depth of 2–4 inches. Grubs are usually small, white, C-shaped, and about the size of a quarter.

Count the grubs in this square. If you find more than five or six, it's likely an infestation. The more you find, the more likely you’ll need to act fast.

Why Grubs Are So Harmful to Your Lawn

Grubs may seem harmless at first—they’re just small larvae, right? But their feeding habits are aggressive. By eating away the roots, they weaken the grass’s foundation, making it harder for the grass to survive drought or other stresses. Over time, these small, pale larvae can kill off large sections of your lawn.

A lawn with a severe grub problem is not only unsightly but also more vulnerable to weed invasion. Without healthy roots, your lawn becomes patchy, and open areas create the perfect spot for weeds to take over.

Preventing Grub Infestations: Steps for a Healthy Lawn

The best way to deal with grubs is to prevent them from becoming a problem in the first place. Here are some expert tips for reducing the chances of a grub invasion:

Water Deeply, But Less Frequently: 

Grubs thrive in consistently moist soil. Water your lawn deeply but infrequently to encourage the grass to develop strong roots, making it less attractive to grubs.

Aerate Your Lawn Regularly: 

Aerating improves drainage and root health. It creates a less welcoming environment for grubs and helps your grass grow stronger. Aerating once or twice a year, especially in the Hamptons' humid summers, can make a significant difference.

Keep Your Grass Healthy and Fertilized: 

Healthy grass is more resilient to pests. A regular fertilizing schedule can keep your grass strong, helping it withstand minor grub damage without showing severe symptoms.

Consider Beneficial Nematodes: 

Nematodes are tiny, harmless worms that attack grubs. Applying them in spring or fall can reduce grub populations without the need for chemical insecticides.

Limit Overwatering in Late Summer: 

Many beetles lay their eggs in the summer, which hatch into grubs by late summer and fall. Reducing watering during this period can make your lawn less appealing for egg-laying beetles.

Natural vs. Chemical Control Methods

For controlling grubs, you have two main options: natural solutions or chemical insecticides. Each approach has its advantages, but your choice may depend on the level of infestation.

Natural Solutions

Natural methods are often a preferred choice for environmentally conscious homeowners. Here’s what you can do:

Beneficial Nematodes: 

As mentioned earlier, these microscopic worms are harmless to humans, pets, and plants but deadly to grubs. Apply nematodes when the soil is moist, either early in the morning or evening. They’ll hunt down grubs and reduce their numbers over time, naturally balancing your lawn’s ecosystem.

Milky Spore Powder: 

This bacterial powder targets Japanese beetle grubs specifically. Spread it across your lawn, and as grubs consume it, the bacteria multiply, creating long-term protection against future grubs. Milky spore can take a few years to establish fully, but once it does, it can provide lasting grub control.

Chemical Treatments

If you have a severe grub problem, chemical insecticides may offer faster results. These treatments are often applied in late summer when grubs are young and more susceptible.

Preventative Insecticides: 

Products containing ingredients like imidacloprid are designed for preventative use, targeting young grubs before they become a major issue. These are usually applied in early summer to prevent eggs from hatching into harmful larvae.

Curative Insecticides: 

For active infestations, curative treatments containing ingredients like carbaryl or trichlorfon can kill mature grubs quickly. Keep in mind that these chemicals can harm beneficial insects, so apply only when absolutely necessary and follow instructions carefully.

While chemical treatments are effective, it’s wise to use them sparingly. Overuse can lead to soil imbalance, harming beneficial organisms and creating other lawn issues. If you're unsure about which treatment to use, consulting with a lawn care specialist can help you select the best solution for your lawn's specific needs.

When to Treat Your Lawn for Grubs

Timing matters when it comes to grub control. Treating your lawn at the wrong time can make treatments less effective. Here’s a quick guide:

Preventative Treatments: 

Apply in late spring to early summer to stop beetle eggs from hatching. This approach works best if you’ve had grub issues in previous years.

Curative Treatments: 

Apply in late summer or early fall when grub damage is first noticed. This is when grubs are actively feeding and causing the most harm, making treatments more effective.

If you live in an area like the Hamptons, where humidity and moisture can attract grubs, staying on top of these seasonal treatments can help you avoid recurring infestations.

Maintaining a Healthy Lawn After Grub Control

Once you’ve dealt with a grub problem, you’ll want to focus on helping your lawn recover. Healthy grass can bounce back from minor damage, but significant grub infestations might need extra care. Here’s how to nurse your lawn back to health:

Reseed Bare Patches:

After removing grubs, reseed the damaged areas. Use a quality grass seed and apply a thin layer of compost or topsoil to help it grow.

Water Consistently but Wisely: 

Young grass needs regular water to establish roots. Water in the morning to avoid excess moisture at night, which can invite more pests.

Fertilize for Strong Root Growth: 

Apply a balanced fertilizer to boost your lawn’s recovery. Strong roots mean your lawn is better equipped to handle pests and stressors.

Mow Carefully: 

Keep your mower blades sharp and avoid cutting the grass too short. Taller grass can shade the soil, making it harder for pests to thrive.

Why Regular Monitoring Is Essential

The best way to keep grubs from overtaking your lawn is through regular monitoring. Set a routine to check for grubs each season, especially in mid-to-late summer when they’re most active. By staying proactive, you can spot early signs of grubs and treat them before they cause widespread damage.

Remember, even if your lawn looks perfect, it can be hiding grubs just below the surface. Catching them early means you won’t have to deal with brown patches or weakened grass later.

When to Call in a Professional

While DIY treatments can be effective, some infestations are best handled by a professional, especially if you’re dealing with a recurring grub problem. A lawn care expert can help diagnose the issue accurately, apply effective treatments, and provide guidance on how to maintain a pest-resistant lawn. Plus, with expertise in local conditions, they can tailor the treatment to factors like soil type, grass variety, and regional pest challenges.

A grub-free lawn is achievable with the right approach. By staying vigilant, using preventive measures, and knowing when to call in the experts, you can enjoy a healthy, green lawn without the worry of grubs. 

With consistent care and attention, your lawn can be a beautiful, pest-free space where you’ll love spending time—and one that’s the envy of the neighborhood.