How to Get Rid of Crabgrass in Ohio — And Keep It From Coming Back
- Timothy Jacobs
- Mar 15
- 4 min read
If you have a lawn in Central Ohio, you've almost certainly dealt with crabgrass. It shows up in June, spreads fast, and by July it can dominate entire sections of the yard. By the time most homeowners notice it and try to do something about it, the best treatment window has already passed. Here's how to get ahead of it.
What Crabgrass Actually Is
Crabgrass (Digitaria sanguinalis and Digitaria ischaemum) is a warm-season annual weed. It germinates from seed in late spring, grows aggressively through summer, sets thousands of seeds in late August and September, and then dies with the first frost. Every year, the seed it produced the previous season germinates again — which is why crabgrass infestations tend to get worse over time if left untreated.
In Central Ohio, crabgrass is most recognizable by:
Wide, flat, light green blades — noticeably lighter than most lawn grass types
A sprawling, low-growing habit that spreads outward in a crab-like pattern
Appearance in thin or bare areas of the lawn, along edges, and in spots where grass is weak
Rapid growth in heat — it takes off in June and July when cool-season Ohio grasses slow down
Why Your Lawn Gets Crabgrass
Crabgrass doesn't randomly invade a healthy lawn. It exploits weaknesses. The conditions it thrives in are the same conditions that mean your turf is stressed:
Thin or sparse turf — bare soil is a welcome mat for crabgrass seeds
Mowing too short — scalped lawns expose soil and let light reach germinating seeds
Compacted soil — crabgrass tolerates compaction better than most lawn grasses
Dry spots — crabgrass is more drought-tolerant than Kentucky bluegrass or tall fescue
Edges along driveways, sidewalks, and curbs — heat-absorbing pavement accelerates germination
This is why weed control without improving the underlying lawn is a losing battle. You can kill the crabgrass, but if the lawn is still thin and stressed, new crabgrass — or other weeds — will fill right back in.
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Pre-Emergent: The Most Effective Tool
The most reliable way to control crabgrass is to stop it before it ever breaks the soil. Pre-emergent herbicides form a chemical barrier in the top layer of soil that prevents seeds from germinating. Applied at the right time, a good pre-emergent will dramatically reduce crabgrass pressure for the entire season.
When to Apply Pre-Emergent in Central Ohio
The trigger for application is soil temperature, not the calendar. Crabgrass germinates when soil temps at a 2-inch depth reach 55°F and hold there for several consecutive days. In Circleville, Columbus, and Lancaster, that typically happens between late March and mid-April.
The target application window is when soil temps are consistently in the 50 to 55°F range — before germination, not after. Once you see crabgrass emerging, the pre-emergent window is gone.
Important Note on Overseeding
Pre-emergent herbicides don't distinguish between crabgrass seeds and grass seeds. If you apply pre-emergent and then try to overseed bare areas, the new seed won't germinate. You have two options: skip the pre-emergent in areas you're overseeding, or use a product with a shorter residual and wait the appropriate interval before seeding. Plan accordingly.
Post-Emergent: What to Do When It's Already Growing
If crabgrass is already actively growing, post-emergent products are your option. Key facts:
Most effective on young crabgrass with 2 to 4 leaves — the smaller, the better
Products containing quinclorac (sold under various brand names) are among the most effective on established Ohio crabgrass
Effectiveness drops significantly once crabgrass matures and begins tillering (branching)
Mature crabgrass in August is very difficult to kill chemically without damaging surrounding turf
Multiple applications are usually needed for heavy infestations
For severe, established crabgrass populations in mid to late summer, the most practical approach is often to manage it through the end of the season and focus on a strong pre-emergent application the following spring — while improving lawn density through fall overseeding and aeration.
Long-Term Control: Build a Denser Lawn
The most sustainable crabgrass control strategy is a thick, competitive lawn. Dense turf shades the soil surface and prevents crabgrass seeds from receiving the light they need to germinate. Here's how to build it:
Mow at 3 to 3.5 inches or higher throughout the season — tall grass shades the soil and outcompetes weeds
Overseed thin areas every fall — September is the ideal time in Central Ohio
Core aerate annually or bi-annually — improves soil health and root depth for a more competitive lawn
Fertilize appropriately — a well-fed lawn outgrows and outcompetes weed pressure
Professional Weed Control Programs
Managing crabgrass properly requires hitting the pre-emergent window at exactly the right time, which requires monitoring soil temps and understanding your specific lawn's history. Many homeowners find it easier — and ultimately less expensive — to hand this off to a professional program that handles the timing automatically.
Lawn Harmony offers seasonal programs that include pre-emergent, post-emergent treatment, and lawn health services for Circleville, Columbus, Lancaster, and all of Central Ohio.
👉 Get Your Free Weed Control and Lawn Care Quote
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Serving Circleville · Columbus · Lancaster · Chillicothe · Central Ohio
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