Round brown patches in grass that keep growing are often called brown patch. In Florida the lawn fungus behind brown circles is named large patch, and UF/IFAS Gardening Solutions says it shows up mostly when temperatures drop below 80 degrees, usually November to May.
That puts it in the cooler months here, not in summer. If your patches showed up in July, look at the other causes on this page first: chinch bugs, grubs, thatch or a sprinkler that misses a spot. Below you will find how to tell them apart, what to change in the yard, what lawn repair costs nationally, and the questions to ask when a crew comes out and measures your yard.
Round brown patches in grass: is it large patch?
What the fungus looks like
UF/IFAS describes large patch this way: it starts as round, discolored patches that grow. The edges are darker, sometimes orange, where the fungus is active, and the center is brown and sunken. The fungus is Rhizoctonia solani, and moisture is the main driver: heavy watering, rain and humidity.
When lawn fungus brown circles appear in Tampa
UF/IFAS puts large patch at the cool end of the year, usually November to May in Florida. Tampa's coolest month is January, with a normal nightly low of 52.8°F (NOAA normals). Tampa averages 49.48 inches of rain a year, and November is the driest month, with 1.40 inches in a normal year.
So where is the moisture coming from in those dry months? Check the sprinkler timer first, for missed or overwatered spots, before you patch anything.
Brown patches in a summer lawn
Tampa summers are hot. The airport records about 94 days a year at 90°F or hotter, and August has a normal high of 91.2°F. Those highs sit well above the 80 degrees below which UF/IFAS says large patch mostly shows up. If the damage is in a summer lawn, look at the causes in the next section before you buy anything for fungus.
One question helps sort the causes: did the patches appear in the warm months or the cool ones? Write the answer down, and note which spots your sprinklers reach, before the crew comes out and measures.
Other causes of brown patches in a Tampa lawn
Chinch bugs
Chinch bug damage shows as yellow to brown patches. In heavily infested St. Augustinegrass the grass turns yellow first, then quickly dark brown, and the center can go dead and bare. UF/IFAS calls chinch bugs the most difficult pest of St. Augustinegrass. They are most active in warm weather, and Tampa is central Florida, so the warm months are the main risk. See our page on chinch bug damage for the full picture.
To confirm them, look at the edge between brown and green grass for tiny black-and-white adults or orange nymphs. You can also vacuum about 1 square foot of that edge and dump it on white paper. Chinch bug injury usually shows first in grass that is water-stressed or in full sun.
Chinch bugs hit stressed turf. Poor sprinkler coverage, mowing too short, too much nitrogen and thatch build-up all invite them. Ask us which grass suits your yard's sun and water before you re-sod after chinch bug damage.
Grubs, mole crickets and webworms
Mild white grub damage leaves turf yellow and is hard to diagnose. Major damage leaves large areas of dead turf.
Mole crickets tunnel through roots. Pour soapy water over a few square feet of turf and they come up, so you can count them. Tropical sod webworms can quickly make a lawn look scalped, and UF/IFAS says the grass usually recovers with proper watering.
Thick thatch and too much water or fertilizer
Too much water or fertilizer and wrong mowing make grass build a thick, spongy mat called thatch. UF/IFAS says it causes serious problems in Florida lawns, and calls it a perfect habitat for chinch bugs. If thatch must be removed, use a vertical mower and water afterward. Sand topdressing is the best biological control, and core aeration helps prevent it. Our page on thick thatch in a lawn goes deeper.
Fairy rings
Rings in a lawn can also be fairy rings. They come from fungi feeding on buried organic matter such as old stumps, lumber and leaves, and they last as long as that food and warm, rainy weather last. UF/IFAS Extension Charlotte County says they do no long-term damage to a lawn. Fungicides only suppress them, while regular mowing and good fertilizing hide the color difference. Treat fairy ring mushrooms as poisonous and remove them so children and pets do not eat them.
What to change to stop lawn fungus
UF/IFAS gives four habits for large patch:
- Water only when needed, and always in the morning.
- Use slow-release nitrogen sparingly.
- Mow sick areas last.
- Clean the mower blades.
For lawn diseases in general it adds: water only when leaf blades curl, do not mow wet grass, use the least nitrogen the grass needs and aerate to cut compaction.
Watering under Tampa's rules
The City of Tampa Water Department lets customers water lawns once a week, on a day set by the last digit of the house number: 0-1 Monday, 2-3 Tuesday, 4-5 Wednesday, 6-7 Thursday and 8-9 Friday. Lawn watering is allowed only from midnight to 4 a.m. or 8 p.m. to 11:59 p.m., never between 4 a.m. and 8 p.m.
The advice is morning watering. If your timer runs in the evening window, ask whether it can run in the midnight to 4 a.m. window instead, which is closer to that morning watering.
The limits apply to everyone, including homes on private wells. Breaking them can bring fines up to $500 and a mandatory court appearance. The regional one-day-a-week order runs until March 31, 2027.
Two more checks from UF/IFAS help: after 0.3 inch of rain in 24 hours, or 1 inch in 3 days, irrigation may not be needed that day. And Florida law requires every automatic lawn sprinkler system to have working technology that stops it when there is enough moisture. A licensed contractor working on a system must test it and fix or add one.
Fertilizer rules in Tampa
In Tampa, lawn and landscape fertilizer with nitrogen or phosphorus may not be applied from June 1 to September 30, according to the City of Tampa. No fertilizer goes within 10 feet of water. Grass clippings, fertilizer and yard waste may not be blown or placed into the street.
Soil, compaction and aeration
North and Central Florida soils are typically very sandy and do not hold water or nutrients well. UF/IFAS Extension Hillsborough County also reports that urban development in Tampa and Hillsborough County often leaves compacted, nutrient-poor sandy soil. Fixes for compacted soil are tilling, plug aeration, air tilling and adding compost. The right one depends on how compacted the soil is and your budget.
Fungicide: when and where
UF/IFAS says fungicides can be used preventively for a disease that keeps coming back, but only on areas with a known problem, never the whole lawn. A preventive fungicide works best about two weeks before symptoms usually appear: the end of September in North Florida, the end of October in South Florida. Tampa sits between those two zones, so ask whoever treats your lawn which date they use.
Cost
Repair, replacement and cost
Before patching dead areas, find what killed them. UF/IFAS says to check the sprinklers for missed or overwatered spots and look for insects or disease. Then remove the dead turf and fill with plugs, sprigs or sod.
UF/IFAS Extension Hillsborough County says to replace a lawn when 30% or more of it is weeds, bare spots or damage. Where damage is extensive, UF/IFAS suggests replacing those areas with a different grass or another plant rather than patching.
Doing the sod work right
Never lay sod over existing weeds and grass. Remove or kill them first, and rototill compacted soil 6 to 8 inches deep. New sod needs light, frequent watering for the first 2 to 3 weeks, kept moist but not soggy. Wait 3 to 4 weeks before the first mow and 30 to 60 days before fertilizing. In Tampa, new sod still may not be watered between 4 a.m. and 8 p.m., and the city points to the UF/IFAS 30-day establishment schedule.
What lawn repair costs
National ranges for the repair steps. This Old House (2026) gives $0.31 to $0.82 per square foot for sod material alone.
| Repair item | National range |
|---|---|
| Remove weeds and old grass, disposal included | $0.88 to $1.84 per square foot |
| Till and grade before new sod | $0.90 to $2 per square foot |
| Sod material alone | $0.31 to $0.82 per square foot |
| St. Augustine sod, installed | $0.98 to $1.79 per square foot |
| Lawn soil test before seeding | $35 to $100 |
What moves the price: how much of the lawn is dead, whether the old grass has to come out, whether the soil needs tilling and grading, and the grass type. For a Tampa number, ask for a written, itemized price after the crew walks your Tampa yard and measures it. Our landscaping cost guide shows more price ranges.
Choosing who treats or re-sods the lawn
The BBB says a company that quotes without seeing the yard cannot know what it needs, so get a price after an on-site look. The FTC says a written estimate should list the work, the materials, the completion date and the price, and that you should compare bids for the same work. Do not pay the full amount up front.
In Florida, anyone applying pesticide to lawns for hire must hold their own FDACS certification or work under a licensed Lawn and Ornamental operator. Ask who will apply any weed or pest treatment and which state licence they hold. For-hire fertilizer applicators must hold a Limited Urban Commercial Fertilizer Applicator Certificate, so just ask the applicator to show it.
FAQ
Is the brown circle in my Tampa lawn brown patch fungus?
It may be, if the patches are round and growing, the edges are darker or orange, the center is brown and sunken, and it is between November and May. Those are the UF/IFAS signs of large patch. Check the edge of the patch for chinch bugs as well, because they can leave yellow to brown patches too.
Can brown patch fungus show up in a summer lawn in Tampa?
UF/IFAS says large patch shows up mostly when temperatures drop below 80 degrees, usually November to May in Florida. Brown damage in July or August calls for a check for chinch bugs, which are most active in warm weather, and for sprinkler problems.
When should I water a lawn with brown patch?
The UF/IFAS advice is to water only when needed and always in the morning. Tampa allows lawn watering only from midnight to 4 a.m. or 8 p.m. to 11:59 p.m., once a week on the day set by the last digit of your house number.
Can I fertilize a lawn that has brown patches?
Not with nitrogen or phosphorus from June 1 to September 30 in Tampa. At other times UF/IFAS says to use slow-release nitrogen sparingly on a lawn with large patch, and fertilizer never goes within 10 feet of water.
How much does it cost to repair a lawn with brown patches?
This Old House (2026) puts sod material alone at $0.31 to $0.82 per square foot, a national range. Installed sod, tilling and removing the old grass add to that, as the table above shows. Ask for a written, itemized price after the crew walks your Tampa yard and measures it.
Cost
Get a written price for your lawn
Call us or use the form. We call you back within one business day. The crew comes out and measures, and you get a written price before any work starts. Contact Tampa Landscaping Pros to book the visit.