Crabgrass Treatment Options in June for Ohio Lawns

I’ve been pushing mowers across Pickaway, Franklin, and Fairfield counties for more than ten years, and the June crabgrass call is the most common weed call I get all year. Somebody skipped or mistimed their April pre-emergent, the crabgrass started showing along the driveway and the south-facing edges in early June, and now they want to know what to do.

This is what I tell every one of those callers, what OSU Extension recommends for post-emergent control on cool-season lawns, and when I tell people to give up on this season and plan for fall.

Why is the pre-emergent window closed in June?

Crabgrass seeds germinate when soil temperatures hold at 55 degrees for 5 to 7 consecutive days, which in Central Ohio is typically the last week of April through the first week of May. A pre-emergent barrier has to be down before that window to stop germination. By June, the seeds have already germinated, the plants are visible, and a pre-emergent chemical does nothing because it only works on ungerminated seeds.

This catches a lot of homeowners. The bag of pre-emergent at the hardware store doesn’t say “useless after May 15,” it just says “crabgrass preventer.” Folks see crabgrass in their lawn in June, buy the preventer, and put it down expecting it to work. It doesn’t, and they’re frustrated.

On a Grove City property I walked last June, the homeowner had put down three rounds of pre-emergent between May 25 and June 15 trying to kill the crabgrass he could see in his lawn. He’d spent about $120 on product that did nothing for his crabgrass and probably stunted his fescue roots from over-application of prodiamine. We pulled samples, identified that what he had was actually established crabgrass plus some smooth crabgrass mixed in, and put together a post-emergent plan.

What are the post-emergent options in June?

Two active ingredients matter for June crabgrass control on cool-season turf: quinclorac and fenoxaprop. Both are selective, meaning they kill crabgrass without killing your tall fescue or Kentucky bluegrass.

Quinclorac (sold as Drive XLR8, Quinclorac 75 DF, and as part of several combo products) works best on young crabgrass with 1 to 4 leaves or already-tillered plants. It’s less effective on the 4 to 6 leaf “teenage” stage. So you want to spray in early to mid June when the plants are small, or wait until they’ve tillered out in late June or July. Quinclorac is also strong on white clover as a bonus.

Fenoxaprop (Acclaim Extra) works across all growth stages of crabgrass but is more expensive and harder to find at consumer retail. Pros use it. Most homeowners end up with quinclorac.

A few application rules:

• Don’t mow for 2 to 3 days before or after application
• Apply when crabgrass is actively growing, not under drought stress
• Add a methylated seed oil (MSO) surfactant for better uptake on quinclorac
• Don’t tank-mix with cool-season grass fertilizer
• Expect to need a second application 14 to 21 days after the first for full control

The quinclorac label warns against application to bentgrass, which most Central Ohio homeowners don’t have to worry about. But if you have a high-end Kentucky bluegrass blend, check the label first. Quinclorac can yellow KBG slightly for a week or two after application.

Why does hand-pulling fail?

Hand-pulling fails because crabgrass is an annual that already dropped seed before you saw it. The plant you pull is just one season’s expression. The seed bank in your soil holds 5 to 7 years of viable crabgrass seed, and pulling one plant doesn’t reduce that bank meaningfully.

It also fails because the act of pulling disturbs the soil, exposes more seed to light, and creates a perfect bare-soil germination site for the next round. You’ll often pull crabgrass and have new crabgrass come up in the same spot within 10 days.

The only situation where hand-pulling makes sense is one or two isolated plants in an otherwise clean lawn, pulled before they go to seed in late July. Pull early, get the whole crown, and over-seed the bare spot with fescue immediately. On any property with more than 5 percent crabgrass coverage, hand-pulling is a waste of a weekend.

On a Lancaster property a client tried hand-pulling last July, she spent two full Saturdays pulling crabgrass from her front lawn. By August it was back, worse than before, because she’d left the soil exposed and the next round of seeds germinated in the disturbed spots. We came in with quinclorac in early August, knocked back what was left, and put her on a fall overseed program.

What cultural controls does OSU recommend?

OSU Extension’s turfgrass weed bulletin is consistent on this: the best crabgrass control is a thick, dense, properly mowed lawn. Crabgrass is a sun-loving annual that cannot establish in shade or in a thick cool-season canopy. Every cultural practice that increases turf density reduces crabgrass pressure for next year.

Specifically:

• Mow at 3.5 to 4 inches, never below 3. Tall mowing shades soil and prevents crabgrass germination by blocking the light it needs.
• Sharpen your blade. A torn cut creates wounds that crabgrass colonizes.
• Fertilize on a fall-heavy schedule (most nitrogen in September and October) to build a dense canopy by spring.
• Water deeply and infrequently to push roots down. Light, frequent watering favors shallow-rooted crabgrass over deep-rooted fescue.
• Aerate compacted lawns in fall. Crabgrass thrives on compaction where desirable grass cannot.

On a Pickerington property I’ve serviced for four years, the homeowner never sprays anything. We mow at 4 inches, fall feed heavy, aerate and overseed every other September. The lawn went from about 30 percent crabgrass when we took over to less than 2 percent now. No pre-emergent, no post-emergent, just dense turf that doesn’t let crabgrass in.

This is the long answer most homeowners don’t want to hear. Sprays handle this season. Mowing height, watering, and fall feeding handle next season and every season after that.

When should I give up and plan for fall overseed?

If your lawn is more than 40 percent crabgrass by mid-June, the cost-effective move is to stop spraying and plan a fall renovation. Here’s why.

Quinclorac on a heavily infested lawn often kills the crabgrass and leaves you with 40 percent bare soil. That bare soil will fill with summer annual weeds (purslane, prostrate spurge, more crabgrass from the seed bank) before fall, and you’ll mow weeds all July and August. Better to let the crabgrass finish out its season as ground cover, knowing it’ll die at first frost, then renovate in September.

The fall renovation looks like this:

• Late August: spray remaining crabgrass with quinclorac to weaken it before frost
• Early September: core aerate
• Mid September: overseed with a quality turf-type tall fescue blend at 6 to 8 pounds per 1,000 sq ft
• Mid September through mid October: starter fertilizer (18-24-12) at planting, then 1 lb N per 1,000 sq ft in early October
• Maintain at 3 to 3.5 inch mowing height through fall
• Following April: pre-emergent (prodiamine or dithiopyr) before soil hits 55 degrees

By the following June, the lawn looks like a different property. We run this exact program through our aeration and overseeding service starting Labor Day weekend, and it books out two to three weeks ahead. On a Circleville lawn I renovated last September that was probably 60 percent crabgrass, the front yard is now solid fescue with maybe 5 percent crabgrass returning. That’s a manageable problem.

Quick June crabgrass checklist

• Identify what you actually have (large crabgrass, smooth crabgrass, or look-alikes like Bermudagrass, dallisgrass, or nimblewill)
• If under 40 percent coverage, spray quinclorac with MSO surfactant in early June, repeat at 14 to 21 days
• If over 40 percent coverage, plan a fall renovation instead of spraying now
• Raise mowing height to 3.5 to 4 inches starting today
• Sharpen the blade
• Book aeration and overseed for September
• Set a calendar reminder for early April pre-emergent next year

Want a written quote?

If sorting through crabgrass options isn’t how you want to spend your weekends, Lawn Harmony Landscaping handles lawn care across Pickaway, Franklin, Fairfield, Ross, and Fayette counties. We’re locally owned and operated, licensed and insured, with a 5.0-star Google rating.

Call (614) 425-9789 or email LawnHarmonyOhio@gmail.com for a free quote. Commercial properties can request a walkthrough at /commercial.

Service area: Circleville, Columbus, Grove City, Bexley, Upper Arlington, Pickerington, Canal Winchester, Groveport, Lancaster, Baltimore, Chillicothe, Washington Court House, and Jeffersonville.

Related reading: lawn mowing service, aeration and overseeding, commercial grounds maintenance.