Summary points:

• Beneficial nematodes can kill grubs effectively, but require careful timing, proper equipment, and seasonal reapplications.

• In severe infestations, a one-time chemical treatment may be the only way to quickly save a lawn.

• ​Adding clover builds long-term resistance against grubs, strengthens soil and improves lawn resilience.

• Milky Spore is another organic option, but it works slowly and is less effective in cooler climates.

If you’ve got a lawn, chances are you’ve got grubs living in the soil. These beetle larvae live almost everywhere, feeding quietly on grass roots without anyone being the wiser. In fact, a handful of grubs (five or fewer per square foot of turf) is considered normal and causes no harm at all. Most of the time, you’d never even know they’re there.

The trouble starts when you give Japanese beetles (the grubs’ parents) an environment for their larva to thrive and their populations to explode. Thick monoculture lawns create the perfect environment for beetles to lay eggs and for grubs to thrive. Once populations climb to 10–12 or more per square foot, damage shows up fast: turf turns brown, thins out and it can be rolled back like a rug because the roots are gone. So the question isn’t whether your yard has grubs, but rather it’s how to keep them from reaching those destructive levels, without resorting to heavy chemical use.

Harnessing Benevolent Nematodes
Entomopathogenic nematodes are microscopic soil-dwelling warriors— Heterorhabditis and Steinernema species, to be precise— that work their way inside grubs, entering through natural openings, releasing bacteria that kill them in about 48 hours, then reproduce inside the cadaver before heading out in search of more prey.

Some field studies show they can reduce grub populations by up to 80%, and trials report up to 96% effectiveness against Japanese beetle grubs. They’re also safe for people, pets and wildlife (grubs notwithstanding).

But nematodes aren’t without their challenges. They require special equipment like a hose-end sprayer. They also have a short shelf life; after they arrive in the mail, if you wait too long to apply, your batch will die. Letting your nematodes set in water too long will also kill them. Timing matters too: soil needs to be moist, temperatures in the right range and applications ideally done in the evening or on cloudy days to protect them from UV rays. Because they don’t live forever, you may need to reapply each season, which can get costly (nematodes are not cheap!). In short: nematodes work wonderfully, but they demand a little planning and care to do their job.

Sometimes You Need Immediate Relief
While nematodes offer an elegant, organic solution, what if you’re dealing with a rapidly deteriorating lawn? Heavy grub populations can devastate roots and turf integrity in a matter of weeks, sometimes before nematodes can fully take effect. In such cases, a targeted, chemical grub control may be the most pragmatic bridge: a precise, one-time, curative treatment to save your lawn while longer-term strategies take root. As an organic lawn company, we don’t recommend synthetic chemicals very often, and when we do, it’s only to use them as a last resort and as minimally as possible. But when it comes to grub treatment, if the options are losing your lawn or saving it with a targeted application of chemicals, we advise using the chemicals.

That said, use the mildest, most turf-specific options available, follow label directions carefully, and always reintegrate organic practices afterward to restore soil life and resilience.
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Introducing Clover: Your Lawn’s Quiet Guardian
Once your grub crisis is under control, it’s now time to invest in long-term prevention, and that starts with biodiversity in your lawn. Specifically, Dutch white clover gives your lawn a sustainable makeover with multiple benefits:

• Grub Suppression — In monocultures, dwarf white clover has been shown to suppress root-feeding grub larvae effectively. Even when mixed with turfgrass, it fosters a healthier soil ecosystem less hospitable to grubs.
  

• Natural Nitrogen Fixer — Clover partners with soil bacteria to pull nitrogen from the air and feed your lawn naturally—reducing the need for synthetic fertilizers and enhancing soil structure.
  

• Drought Resilience & Shade Mitigation — Clover’s groundcover shades soil, curbing water evaporation and helps grass survive dry periods with less irrigation.
  

• Pollinator-Friendly — Its tiny blossoms attract bees and beneficial insects—adding biodiversity and beauty in one fell swoop.
  

But What About Milky Spores?
Another organic option you may hear about is Milky Spore (Paenibacillus popilliae), a bacterium that specifically infects and kills Japanese beetle grubs. Once established, it spreads naturally as infected grubs die, releasing billions of spores back into the soil. On paper, that sounds like the perfect solution—long-term control that can last for decades.

Here’s the catch: Milky Spore is a slow burn. It can take 3 to 5 years before it fully infiltrates the soil and begins noticeably reducing grub populations. That makes it a poor option for immediate relief when your lawn is under siege.

There’s also the climate factor. Milky Spore thrives in warm soils, typically in the southern U.S., where soil temperatures support the bacterium’s spread. In cooler northern regions, like the Midwest and Northeast, the bacteria reproduce less efficiently. Fewer infected grubs means fewer spores in the soil, which limits its long-term effectiveness.

So while Milky Spore can be a useful tool under the right conditions, think of it more as a long-term preventative measure—not a quick fix when grubs are actively chewing through your turf.