Free your lawn from greedy grubs
You’ve done everything possible—watered, fertilized, weeded—to achieve the brightest, fullest lawn on your street when suddenly several brown patches emerge, much to your bewilderment. The answer lies deep in the soil: lawn grubs. These hungry little pests love to eat your grass’ roots and can cause major damage to your lawn in just a single summer. If you suspect an infestation, this guide will show you how to get rid of grubs and get your grass back to its healthy and flourishing state.
What Are Grubs?
Usually white and c-shaped, lawn grubs—also known as grub worms—are the larvae of beetles, such as June bugs, Japanese beetles, and European chafers. Adult worms will emerge from your soil, mate, and lay eggs over about two to three weeks in the summertime. They multiply fast and feed on grass roots and other organic matter in the soil, cutting your grass off from food and nutrients it needs to thrive.
Why Lawn Grubs Are Bad for Your Yard
Grubs are a one-way ticket to a patchy, brown lawn. These pests feed on underground grass roots, essentially destroying your lawn from the bottom up. Once the roots are damaged, your lawn won’t be able to absorb water or nutrients, and it will start to die. Luckily, the healthier your grass is, the more it can tolerate a small number of grubs. You’ll still want to control the problem before it grows (and before you need to reseed your lawn).
Signs You Have a Lawn Grub Problem
Grubs aren’t always a problem. It is natural to find some grubs in your lawn, but a large number will damage your grass. If you have a full-on grub infestation, you might notice:
There are brown or yellow patches on your lawn.
When you walk over these patches, they feel soft and spongy.
An increase in birds, particularly crows, on your lawn.
An increase in moles on your property, as well as raccoons, skunks, and other critters who snack on grubs
More beetles around your yard.
Here’s how to further confirm you have a grub problem:
Remove a square foot of sod about 3-inches deep from one of the browning patches.
Dig around and look for larvae—they’re milky white, c-shaped, and range in size from half-an-inch to 1-inch long, depending on the beetle species.
If your hunt unearths more than five, you’ve got an infestation
If you’ve done some digging and still aren’t sure, contact a pest inspection company near you to be sure. The average pest control service cost is $200 to $600, and you’ll be happy you eradicated these worms when you get back to enjoying summer days on your freshly cut, lush lawn.
How to Get Rid of Grubs With 6 Simple Methods
Now that you know you have an infestation, here are the best methods to eradicate these pests from your yard.
1. Release Beneficial Nematodes
Nematodes are tiny, microscopic worms that live in soil. There are many varieties, but some of the beneficial ones (Heterorhabditis bacteriophora) will completely ignore your plants and only target soil-dwelling insects. While beneficial nematodes start to work within 48 hours, it may take three years for full eradication using this method alone.
To add nematodes to your yard, buy some from a garden store or nursery, and water the soil before and after application. Because they are living creatures, you’ll want to release them as soon as you get them.
2. Use Milky Spore
Milky spore (Bacillus popilliae) is sold in powder form and can be added to your soil to develop a bacterial environment known as milky disease, which spells bad news for grubs but isn’t harmful to your grass. Like nematodes, the milky disease will take a few years to develop.
3. Consider Pesticides
If you don’t want to wait the three or more years it takes for nematodes and milky spore to work their magic, you might want to employ grub control pesticides. Be warned that some of these chemicals can also kill helpful insects and might be harmful to kids and pets. If the idea of handling these chemicals yourself concerns you, consider hiring a lawn pest control company.
“Make sure not to get any chemicals on flowers—where bees could ingest them—and read all the labels to understand any warnings and application procedures,” says Tara Dudley, Angi Expert Review Board member and owner of Plant Life Designs.
There are two types of pesticides, curative and preventative:
Curative insecticides are designed to eradicate immature larvae (not pupae) and should be applied at the end of summer or early fall when the larvae are chowing down on your grass roots. Common curatives include carbaryl and trichlorfon.
Preventative insecticides won’t do much about the grubs already in your yard, but they’ll prevent future grubs from taking up home in your yard. Merit and Mach 2 are popular brands.
4. Dry Them Out
Lawn grubs need moisture, so it’s possible to starve them of the water they need to grow. If you live in a warm, dry climate, stop watering your lawn for three to four weeks; this will cause any existing eggs to die. Your grass will dry up, but if it was in a healthy state to begin with, it should grow back without any issue.
5. Encourage Birds
Birds are natural predators that love to snack on grubs. You might already notice some floating around your yard pecking at the grass. Though it’s not always the most reliable method, you can try to control a minor grub problem by encouraging birds to frequent your yard. Add bird-friendly accessories like bird feeders, bird baths, and bird houses near areas of infestation.
Keep in mind that if you have a large infestation, you may attract too many birds. All that pecking can tear up your lawn—but in small doses, it actually aerates it. For this reason, only use this method if you have a minor issue.
6. Use Neem Oil
Neem oil is a remedy that disrupts insect growth cycles, effectively killing lawn grubs before they have a chance to reproduce further. How? It stops grubs from eating (so they eventually die) and causes infertility (hello, less grubs in the future). Spray your lawn a maximum of once a week using a DIY spray made from:
1 gallon of water
1 teaspoon of castile soap
2 tablespoons of neem oil
Though neem oil is safe for pets and earthworms, it can harm bees, ladybugs, and other insects while airborne. For this reason, it's best to spray neem oil in the evenings. After about 45 minutes, the oil will evaporate, but the effects are long-lasting.
How to Prevent Grubs From Infesting Your Lawn
Controlling grubs starts by preventing them with a healthy lawn. You can hire a lawn care service near you, or you can roll up your sleeves and follow this lawn maintenance checklist. Beyond strengthening your lawn, here are some other things you can do.
1. Dethatch and Aerate
Compacted soil is the ideal place for beetles to lay their eggs, so make sure to aerate problem areas of your lawn. The same goes for dethatching. Thatch provides cover for grubs, protecting them from the elements, and it harbors moisture, which helps grubs thrive. Hire a lawn dethatching service to make your oh-so-hospitable lawn a little less welcoming.
2. Don’t Overwater
Since grubs thrive on moisture, it’s important that you don’t overwater your lawn—especially during rainy seasons. In early spring, avoid watering when it’s already rained. If it hasn’t rained for a week or two and the ground isn’t frozen, you can provide one inch of water.
During the summer, your lawn will need one to one 1/2 inches of water a week, spread out across two to three waterings. This helps encourage deep root growth, which will stand up to hungry grubs. If the temperatures are super hot, you can add half an inchmore.
3. Apply Preventative Insecticides
If you had a problem with grubs in the past, preventative insecticides are the way to go. Make sure you apply the product in the spring or early summer before grubs have a chance to hatch. Always follow the manufacturer's instructions, and wear protective eye and hand gear when applying.
4. Adjust Your Mower Height
Deter grubs by keeping your grass a little longer during the summer. Female beetles prefer to lay their eggs in moist lawns, where the sun can warm the soil. Avoid a close crop, and stick with a height of three to four inches.
DIY vs. Hiring a Pro
If you’ve got a minor grub problem, DIY methods may be enough to solve the issue for the season. As long as you stay on top of lawn care, you may even be able to stave off the grubs for good. That being said, some infestations are harder to get rid of than others.
At a certain point, when other DIY methods fail, many homeowners feel the need to turn to insecticides. Though effective, insecticides can harm beneficial insects and damage your lawn and garden when used in high concentrations. If you've got a particularly tough infestation, you should hire a local pest control company specializing in lawn pests.
What is the best way to kill lawn grubs?
Insecticides are the most effective way to kill grubs. But prevention is the key solution to the problem. Grubs are no match for a healthy lawn, so keep up your lawn care throughout the spring and summer during grub season.
How do you get rid of grubs naturally?
Some of the best ways to get rid of grubs naturally and without insecticides are:
Introducing beneficial nematodes
Introducing milky spore disease
Applying a DIY neem oil spray
Limiting lawn watering
Encouraging birds and grub-eating critters
What is the best time to treat for grubs?
In most of the United States, the best time to treat grubs is early spring—but it depends on the method. Signs of grub damage usually emerge in May, so you can use a curative insecticide as soon as you notice. This works well on larger grubs that are present in the spring.
That being said, preventative insecticides are usually more effective. You can use these in June or July when grubs first hatch (though check the manufacturer’s instructions because it depends on the ingredients). Introduce nematodes in late summer or early fall when grubs are still young.