St. Augustine vs. Bahia lawns — Sebastian, Florida

St. Augustinegrass is the better fit for irrigated Sebastian lots and for yards near the Indian River Lagoon, while bahiagrass fits large unirrigated lots on acidic sand where a coarse, low input lawn is acceptable.

The two grasses sit at opposite ends of the UF/IFAS comparison table that covers Sebastian and the rest of Florida. St. Augustinegrass is the most commonly used lawn grass in Florida (UF/IFAS). Bahiagrass was introduced from Brazil in 1914 and was originally used as a pasture grass on sandy soils (UF/IFAS). That pasture origin explains most of its behavior on a Sebastian Highlands lot: deep roots, low fertilizer demand, and a thin, open turf that never forms a dense carpet.

The table reads differently on each side of U.S. 1 in Sebastian. East of the highway, along Indian River Drive and the streets near Riverview Park, salt is the deciding factor. West of it, across the Sebastian Highlands toward Barber Street and CR 512, water, shade and budget usually decide. The UF/IFAS selection guide rates maintenance as low for bahiagrass and medium for St. Augustinegrass (UF/IFAS).

Salt rules out bahiagrass on Sebastian lots exposed to Indian River Lagoon spray or brackish irrigation, and alkaline fill sand pushes it toward yellowing, while St. Augustinegrass tolerates both conditions better.

UF/IFAS explains that salt stress in coastal turf comes from irrigation water, saltwater intrusion and salt spray from the ocean. Zoysiagrass, bermudagrass and St. Augustinegrass all tolerate moderate to high levels of salinity, while bahiagrass and centipedegrass have less salt tolerance (UF/IFAS). In the same table, bahiagrass salt tolerance is rated very poor. A bahia lawn on Indian River Drive or on a canal lot near the Sebastian River therefore starts with a handicap that no mowing schedule fixes.

Soil pH is the second filter. Many coastal regions of Florida tend to have sandy, high-pH soils, and St. Augustinegrass can tolerate a range of pH levels from acidic to mildly alkaline (UF/IFAS). Bahiagrass prefers acidic soils. On any Sebastian lot that tests above neutral, UF/IFAS warns that bahiagrass is susceptible to iron deficiency above pH 7.0, which shows as yellow leaf blades, and calls such a site not an example of right plant, right place (UF/IFAS).

Shade is the third filter for Sebastian yards under tree canopy between U.S. 1 and the lagoon. St. Augustinegrass and zoysiagrass have good shade tolerance compared with other warm season grasses, but still need daily sun for most cultivars. Floratam, the most planted cultivar, does not persist well in places that receive less than 6 hours of sunlight daily (UF/IFAS).

Bahiagrass survives Sebastian's two-day irrigation schedule by going dormant and brown in droughts, while St. Augustinegrass stays green only if each permitted watering day delivers 1/2 to 3/4 inch.

The City of Sebastian sets the calendar. Landscape irrigation at odd numbered addresses must only occur on Wednesday and Saturday, and at even numbered addresses or no address on Thursday and Sunday, never between 10:00 a.m. and 4:00 p.m. (City of Sebastian). The city adopted the schedule to comply with St. Johns River Water Management District regulations, and the ordinance carries its own exceptions and variances.

Inside that schedule, UF/IFAS gives the same rule for both grasses: water when leaf blades fold, wilt or turn blue-gray, or when footprints stay visible, and apply 1/2 to 3/4 inch, which wets roughly the top 8 inches of soil where most roots are (UF/IFAS). On fast draining Sebastian sand that amount matters more than run time, so a catch-can test of each zone is the UF/IFAS method for setting the clock.

The grasses part ways in a Treasure Coast dry spell. During extended drought, bahiagrass goes into a drought-induced dormancy and turns brown until conditions favor regrowth, and it generally recovers soon after rain or irrigation returns (UF/IFAS). St. Augustinegrass requires water to stay green and may need supplemental irrigation in extended dry periods. CitraBlue, a University of Florida cultivar on the market since 2018, is described as more drought tolerant than Floratam, Palmetto and Raleigh (UF/IFAS).

Sebastian falls in the UF/IFAS central Florida region, where St. Augustinegrass takes 2 to 5 pounds of nitrogen per 1,000 square feet a year and bahiagrass 1 to 2, all applied outside the county's June 1 to September 30 ban.

UF/IFAS defines central Florida as anything south of Ocala to a line extending from Vero Beach to Tampa (UF/IFAS). Sebastian, north of Vero Beach in Indian River County, sits inside that band, so the central rates apply rather than the year-round south Florida program. The first application of the year is generally early April in central Florida. Bahiagrass may be fed in 1 to 3 applications from spring green-up through fall (UF/IFAS).

Section 50-5 of the Sebastian city code narrows that window for every Sebastian lawn. Fertilizer containing nitrogen or phosphorus cannot be applied to turf from June 1 through September 30, and nitrogen fertilizer must contain at least 50 percent slow release nitrogen (City of Sebastian). The city also bars nitrogen or phosphorus fertilizer before seeding or sodding a site or for the first 30 days after, and bars phosphorus unless a soil or plant tissue deficiency is verified. The Indian River County ordinance applies in the unincorporated areas (Indian River County). In practice a new Sebastian lawn laid in May cannot be fed until October.

Bahiagrass fits that calendar easily. A light spring feeding and one in October covers its 1 to 2 pound range. St. Augustinegrass at the upper end of its range needs several spring and fall applications, and UF/IFAS notes that excess nitrogen and water encourage large patch disease and thatch (UF/IFAS). The City of Sebastian Natural Resources Board posts the City Fertilizer Ordinance and a list of ordinance compliant fertilizers on its landscaping page (City of Sebastian).

Chinch bugs and summer gray leaf spot are the main threats to St. Augustinegrass in Sebastian, while mole crickets and the wrong weed-and-feed product are the main threats to bahiagrass.

Floratam was released jointly in 1973 by the University of Florida and Texas A&M University, and it is the most widely produced and used St. Augustinegrass in Florida (UF/IFAS). Its early chinch bug resistance has largely been lost, and chinch bugs are now a major pest of Floratam. Damage appears first as warm weather arrives, along sidewalks and driveways in full sun, which describes many Sebastian Highlands front yards. Gray leaf spot occurs during the summer rainy season, the same months the city fertilizer ban is in force.

Nematodes favor sand. UF/IFAS reports that nematode populations in St. Augustinegrass typically peak in late April to early May and again in late August to early September (UF/IFAS). The UF/IFAS selection table rates bahiagrass nematode tolerance excellent because of its deep root system, which is one reason it persists on the poorest sand west of the Sebastian Highlands.

The most serious insect threat to bahiagrass is the mole cricket, which tunnels and damages roots (UF/IFAS). Weed control is the other hazard: many popular weed-and-feed products for Florida lawns contain atrazine or metsulfuron, and UF/IFAS states that both herbicides will damage bahiagrass. A product labeled for a St. Augustine lawn on one Sebastian street can kill a bahia lawn next door.

The UF/IFAS Master Gardener plant clinic at the North Indian River County Library on Sebastian Boulevard, open Wednesdays from 10:00 a.m. to noon, is the closest free source of lawn diagnosis for Sebastian residents.

UF/IFAS Extension Indian River County lists the Sebastian clinic at the North IRC Library, 1001 Sebastian Blvd. (CR 512), on Wednesdays from 10:00 a.m. to 12:00 p.m., alongside weekday hours at the Extension office in Vero Beach (UF/IFAS Extension Indian River County). A chinch bug sample, a gray leaf spot blade or a mole cricket can be checked there before any product is bought.

Soil comes first in the UF/IFAS selection advice, because pH decides whether bahiagrass can thrive at all. The Indian River County Extension office offers free residential soil pH testing for Indian River County residents, with nutrient testing available through the UF/IFAS soil lab (UF/IFAS Extension Indian River County). A pH test is the cheapest way for a Sebastian, Roseland or Wabasso homeowner to rule bahia in or out before sod is ordered.

Spreaders, soil test supplies and slow release fertilizers that meet the city rules are listed among lawn and grow supplies on Digital Towns Market. Digital Towns Market is our marketplace. Last verified: October 10, 2026, on the City of Sebastian website, with the lawn fertilizer rules checked against Section 50-5 of the Sebastian city code.