End of August Lawn Checklist for Central Ohio

The last week of August is the most important planning week of the year for a Central Ohio lawn. The cool-season grass is about to wake up from its summer stress dormancy, the soil is still warm enough for fast seed germination, and the calendar is closing in on the prime aeration and overseed window. Anything you do between now and the third week of September has outsized impact on what the lawn looks like in May 2027. I’ve been running mowers and aerators across Pickaway, Franklin, and Fairfield counties for more than ten years, and the homeowners who get this stretch right are the ones with great lawns next year.

Here’s the checklist I run on my own clients’ properties in the last week of August, plus what to skip and what to plan.

What’s the single most important thing to do this week?

Schedule the September aeration and overseed.

If you do nothing else from this checklist, get aeration and overseed on the calendar between Labor Day weekend and the third week of September. Per OSU Extension turfgrass guidance, that two-to-three-week window is when cool-season grass seed germinates fastest and most reliably in Central Ohio. Soil temperatures at 4 inches sit in the mid-60s, daily highs are cooling, nighttime humidity is still up, and rainfall odds are better than they were in July and August.

On a Lancaster property I service, the homeowner moved his annual aeration from late August to early September three years ago because that’s when I had a slot. The lawn that year filled in dramatically better than any of the prior years. That wasn’t a coincidence — soil temperature data from NWS Wilmington in the second week of September is almost always more favorable than the third week of August. Earlier isn’t always better.

Slots fill up. My calendar typically fills within two weeks of Labor Day. If you want a specific date, get on the list now. More on the process in our aeration and overseed service page.

What about a soil test?

Yes, if you’ve never done one or if the last one is more than four years old.

Pickaway County Extension and Franklin County Extension both run soil tests through OSU’s lab for around $15 to $20 per sample. The test tells you soil pH, organic matter percentage, and major nutrient levels. Knowing your numbers prevents the most common fertilizer mistake I see, which is dumping nitrogen on a lawn that actually needs phosphorus and lime.

I tested a Circleville lawn three years ago that the owner had been fertilizing aggressively for a decade. The test came back showing pH of 5.4 — far too acidic for tall fescue, which prefers 6.2 to 6.8. The lawn’s struggle wasn’t a nitrogen problem at all. We applied lime that fall, retested two years later, the pH was back at 6.4, and the lawn responded to a normal feeding schedule the way it should have all along.

Soil test now, get results back in two to three weeks, apply lime or other amendments before the ground freezes. The work pays off for the next decade.

What should the lawn look like right now?

Probably not great. That’s fine.

Central Ohio cool-season lawns are typically in their worst condition of the year in mid-to-late August. The grass has been stressed by July heat, possibly by drought, and definitely by the cumulative wear of the summer. Thin patches, weed pressure, and overall fade are normal in this stretch.

What you’re looking for to plan the fall work:

• Bare patches and thin areas. Mark them mentally. These are overseed targets.
• Crabgrass coverage. Mature crabgrass is going to die at first frost regardless. Don’t waste money treating it now. Plan a stronger pre-emergent program next April.
• Compaction. Walk the lawn. Anywhere it feels rock-hard underfoot is an aeration priority.
• Standing water signs. Yellow grass, moss, soft underfoot. These zones need drainage attention, not more grass seed.
• Weed pressure. Broadleaf weed counts up close. Fall is the right window to spot-treat dandelions and clover.

What watering should I be doing right now?

If we’re in a dry stretch, water deep once or twice a week. If we’ve had rain, water nothing.

Per OSU Extension irrigation guidance, cool-season grass needs about an inch of water per week including rainfall, delivered in deep infrequent sessions rather than daily light watering. In late August, the lawn is starting to come out of summer dormancy and the roots are reactivating. Light daily watering trains shallow roots right when you want them to push deep before the fall growth surge.

If you’re about to overseed in the next two weeks, hold heavy watering until after the seed goes down. Seeded zones need light frequent watering for the first ten days after seeding, then transition to deep infrequent watering as the seedlings establish. Pre-loading the soil with deep moisture now is fine. Soaking it daily is not.

When should I do the fall fertilizer application?

Two windows: mid-September and mid-October.

The mid-September feeding goes down two weeks after seeding, at the bag rate of starter fertilizer (typically something like 18-24-12). Higher phosphorus helps root establishment on new seedlings.

The mid-October feeding is the big one. Nitrogen at 0.75 to 1.0 pound of actual N per 1,000 square feet, slow-release source. This is the application that builds the root carbohydrate reserves the lawn will draw on next summer.

Per OSU Extension fertility recommendations, total annual nitrogen for tall fescue should land between 2 and 4 pounds per 1,000 square feet, with most of it applied in fall. Spring nitrogen pushes top growth at the expense of roots. Fall nitrogen builds the lawn for the long haul. If you have to pick which season to fertilize, fall wins every time.

What about weed control before fall?

Spot-spray in the next two weeks. Broadcast treatment after seeding is off the table.

If you have a real broadleaf pressure — dandelions, clover, plantain, ground ivy — late August through early September is a good window to spot-spray with a targeted post-emergent before you overseed. The herbicide breaks down before the seed germinates, and you’ve taken out the competition.

Once you overseed, you can’t broadcast post-emergent for at least four to six weeks because the herbicide will damage new seedlings. If you didn’t get the weed treatment done before seeding, plan to spot-treat in mid-October or wait until next spring.

For crabgrass specifically, don’t bother spraying mature crabgrass in late August. The plant is going to die at first frost. Spend the money next April on a strong pre-emergent program instead.

Should I be mowing differently right now?

Same height as the rest of the season. 3.5 to 4 inches.

A lot of homeowners drop the deck in late August thinking they’re prepping for fall. That’s backwards. Tall cut equals deep roots equals faster recovery from summer stress. Short cut now stresses an already stressed lawn and slows the September recovery.

Sharp blades, alternating stripe direction, and never more than one-third of the blade off in a single pass. The same rules apply year-round on Central Ohio cool-season turf.

If you’ve been mowing weekly all summer and the grass isn’t really growing anymore, you can stretch to ten days between cuts during dry late-August stretches. The grass tells you. If it’s growing, cut it. If it isn’t, leave it alone.

If you want to hand the schedule off, our lawn mowing service handles weekly maintenance the same day each week and adjusts during drought rather than padding the bill.

What about hedge and bed work?

Light hedge cleanup is fine now. Heavy pruning waits.

Per OSU Extension pruning guidance, most flowering shrubs in Central Ohio shouldn’t take a hard pruning in late August because the new growth won’t harden off before frost. Boxwood, privet, holly, and yew can handle a light shape-up. Hydrangea, viburnum, lilac, and forsythia should wait until late winter or the appropriate post-bloom window for that species.

Bed work is fair game. Pull weeds, cut back perennials that have gone leggy, top-dress mulch where the existing layer has thinned. A fresh half-inch of hardwood mulch on top of last spring’s install restores color and definition cheaply.

End of August checklist summary

• Schedule aeration and overseed for early-to-mid September
• Submit a soil sample to county extension if it’s been four-plus years
• Walk the lawn and mentally mark bare patches, compaction zones, and weed pressure
• Spot-treat broadleaf weeds before overseeding
• Continue mowing at 3.5 to 4 inches with sharp blades
• Hold off on broadcast fertilizer until mid-September starter and mid-October feed
• Light hedge cleanup, skip heavy pruning
• Top-dress mulch on entry beds and high-visibility zones
• Plan fall leaf-cleanup approach now, before the canopy starts dropping

Want a written quote on fall service?

Lawn Harmony Landscaping handles fall aeration and overseed, fall fertilization, hedge cleanup, mulch top-dress, and full-season maintenance across Pickaway, Franklin, Fairfield, Ross, and Fayette counties. Locally owned, owner-operated.

Call (614) 425-9789 or email LawnHarmonyOhio@gmail.com for a written quote. You can also grab a fast residential estimate at our free quote page. Commercial properties can request a walkthrough at /quote/commercial.

Service area includes Circleville, Columbus, Dublin, Upper Arlington, Worthington, Gahanna, Grove City, Pickerington, Canal Winchester, Groveport, Lancaster, Chillicothe, and Washington Court House.