Brown rings or circular patches that appear in a Savannah lawn in fall and again in spring are usually large patch, a disease caused by a Rhizoctonia fungus that attacks zoysia, St. Augustine and centipede. UGA Extension's advice is to avoid nitrogen fertilizer while the soil is below 70 °F (late fall and early spring), improve drainage, core-aerate and water less often. If your lawn has a history of large patch, a preventive fungicide in September or October, with a spring follow-up, is the recommended chemical step (UGA Extension, Dougherty County; UGA CAES Field Report).
What large patch looks like
Large patch shows up as brown or straw-colored rings and patches in warm-season turf during the cooler shoulder seasons — fall, as the grass slows down, and spring, as it greens up. The three grasses UGA names are zoysia, St. Augustine and centipede, three of the main lawn grasses on the Georgia coast. Bermuda lawns are not on that list. If you are not sure what grass you have, the best grass for Savannah lawns guide covers how the main types differ.
Timing is the clue. Brown areas in the heat of July in sunny St. Augustine point more toward chinch bugs or dry soil. Rings that appear as nights cool in October and November, or linger into the spring green-up, fit large patch.
Why Savannah lawns are prone to it
UGA's cultural advice centers on moisture and drainage, and much of the Savannah area sits on wet ground. In the NRCS soil survey for Bryan and Chatham counties, most of the leading soil types are rated poorly or very poorly drained. Ellabelle soils, for example, have a water table “at or near the surface for more than 5 months each year,” and Chipley sands have a seasonal high water table 18 to 36 inches down for two to four months in most years (NRCS Ellabelle; NRCS Chipley). Add 48 inches of rain a year, nearly half of it from June through September (NOAA 1991–2020 normals), and many yards stay damp well into the fall.
Step 1: Fix the water
- Water less often. UGA lists less frequent watering as a large patch control. Savannah already limits irrigation to three days a week by address, with no Fridays and no watering from 10 a.m. to 4 p.m. (see the Savannah watering schedule). In fall, when rain and cooler weather keep soil moist, many lawns need even less. Aim for UGA's overall guideline of about an inch a week from rain plus irrigation, in the early morning.
- Check the sprinklers. Heads that spray the same low spot twice, or a controller still on a summer program, keep the problem areas wet. An irrigation repair visit can rebalance zones and coverage.
- Improve drainage. Look at where downspouts empty and where water stands after a storm. Low spots that stay soggy are where rings tend to return.
Step 2: Core-aerate
Core aeration is on UGA's list of large patch controls because it helps water move into the soil instead of sitting at the surface. Published cost guides put core aeration at $71 to $190, averaging about $131 — typical ranges from published cost guides (2026), estimates, not quotes. See the Savannah lawn care and landscaping prices page for other services.
Step 3: Time your nitrogen
UGA's large patch guidance is to avoid nitrogen when soil is below 70 °F, which in practice means skipping late-fall feedings and not pushing an early-spring application. You can check current soil temperatures on the UGA Weather Network. This lines up with other south Georgia extension advice: feed warm-season lawns after green-up and in midsummer, with no fall feeding (UGA Extension). Centipede in particular needs little nitrogen at all; the centipede grass care guide covers its lighter schedule.
Step 4: Preventive fungicide, if the lawn has a history
For lawns that have had large patch before, UGA recommends a preventive fungicide in September or October, with a spring follow-up. The word that matters is preventive: the application goes down before the rings show up, in the fall window. Use a product labeled for large patch on your grass type and follow the label. For a lawn that has never had it, the cultural steps above come first.
If you would rather have a company handle the fungicide along with your weed control and fertilization, ask what product they use, when they apply it and whether the spring follow-up is included. Ask any company that offers fungicide or other pesticide treatments for its Georgia Department of Agriculture license number, too.
Georgia license check. In Georgia, a business that applies pesticides — including weed killers, weed-and-feed, insect, fire ant or mosquito treatments — to someone else's property for a fee needs a Pesticide Contractor License from the Georgia Department of Agriculture, with a certified commercial applicator on staff (O.C.G.A. § 2-7-99). Lawn and shrub work falls under applicator Category 24 (Ornamental and Turf); mosquito control is Category 41. Ask for the license number and check it with the Georgia Department of Agriculture. Treatments around the home's foundation fall under Georgia's Structural Pest Control Act — ask for the company's structural pest control license.
This is general information, not legal advice.
No reliable local average was published for lawn treatment applications in Savannah — get two or three quotes. The price depends on lawn size, the number of applications and whether it is part of an ongoing plan.
Repairing damaged areas
Once the conditions behind the disease are corrected, check the rings again after spring green-up. Areas that have not filled in can be patched with sod of the same grass. Published cost guides put installed sod at about $1 to $3 per square foot (estimates, not quotes); see sod installation in Savannah. Fix drainage and watering first so new sod does not go into the same conditions.
The short version
Brown rings in zoysia, St. Augustine or centipede in fall or spring are usually large patch. Water less often, improve drainage, core-aerate, hold nitrogen until soil is above 70 °F, and, if the lawn has a history of the disease, apply a preventive fungicide in September or October.
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