Lawn Care
St. Augustinegrass: Mowing Height, Sod, Plugs and Lawn Care
Quick answer
St. Augustinegrass is the most shade-tolerant warm-season lawn grass, grown in zones 8 to 10 along the Gulf and Atlantic coasts. It is planted from sod or plugs, not seed. Mow it high at 2.5 to 4 inches, feed 2 to 5 pounds of nitrogen a year, and check for chinch bugs in hot weather.
St. Augustinegrass is the wide-bladed, blue-green carpet of coastal southern yards. It spreads by thick above-ground stolons, establishes quickly from sod, tolerates salt spray and sandy soil, and takes more shade than any other warm-season lawn grass. It is also the coarsest common lawn grass, the least cold hardy, and the one most likely to be wrecked by an insect, because chinch bugs and the viral St. Augustine Decline both target it.
The first thing to know is that St. Augustine is not sold as seed. Commercial cultivars such as Floratam, Palmetto and Raleigh produce little viable seed, so lawns start from St. Augustine sod or from plugs. Skip the seed math and use the fertilizer calculator for feeding rates and the lime calculator only if a soil test calls for it.
On this page
What are the key numbers for a St. Augustine lawn?
| Trait | St. Augustinegrass |
|---|---|
| Season type | Warm-season; browns after frost and greens up as soil warms |
| USDA zones and region | Zones 8 to 10; Gulf Coast, Florida, coastal Carolinas, southern Texas and coastal California |
| Mowing height | 2.5 to 4 in; Floratam and other coarse types do best at 3.5 to 4 in |
| Seeding rate | Not applicable: sod or plugs only, since it is not sold as viable seed |
| Germination | Not applicable; plugs root in about 2 to 3 weeks and sod knits in 2 to 4 weeks |
| Shade tolerance | Best of the warm-season grasses; handles about 4 to 6 hours of sun |
| Drought tolerance | Fair to good; wilts sooner than bermuda or zoysia and needs irrigation in dry spells |
| Wear and traffic | Poor; stolons tear under heavy foot traffic and it is not a good play-area grass |
| Nitrogen per year | 2 to 5 lb N per 1,000 sq ft, in the warm months only |
| Soil pH | 6.0 to 7.5; tolerates sandy, alkaline coastal soil |
| Spreading habit | Thick above-ground stolons, no rhizomes |
| Main pest | Southern chinch bug, which kills patches in hot, sunny, dry weather |
Ranges follow common Gulf Coast extension guidance. Cultivars differ, so confirm with the sod farm tag.
How do you plant St. Augustinegrass without seed?
Two routes, both starting in late spring or early summer once soil holds 65 to 70 F and the lawn has the full warm season to root.
| Factor | Sod | Plugs |
|---|---|---|
| Instant coverage | Yes, a finished lawn the day it is laid | No, gaps stay open for a season |
| Time to full cover | 2 to 4 weeks to root and knit | One full growing season, sometimes two |
| Cost per 1,000 sq ft | Highest of the options | A fraction of sod, more labor |
| Best use | A whole new lawn, or erosion-prone slopes | Patching thin areas and filling a partly grassed yard |
| Water needed after planting | Daily light watering for about 2 weeks, then taper | Daily for the first 2 weeks at the plug, then taper |
| Weed pressure while filling | Low, the canopy closes immediately | High, open ground between plugs invites weeds |
| Typical spacing | Solid coverage | 12 to 18 in apart, closer fills faster |
Both routes want the soil loosened and graded first, and neither should go down on frozen or waterlogged ground.
How high should St. Augustine grass be mowed?
Mow St. Augustinegrass at 2.5 to 4 inches, and keep coarse cultivars like Floratam at the top of that range. This is the opposite of bermuda: cutting St. Augustine short weakens it, exposes the stolons to sun scald and opens the canopy to weeds. In shade, mow at the very top of the range so the longer leaf can catch what light there is.
Mow with a sharp blade and only when the grass is dry, since the wide blades shred and mat when wet. The EGO POWER+ LM2135SP 21 in. Select Cut Self-Propelled Mower Kit covers 1 to 4 inches and the EGO POWER+ LM2114 21 in. Push Mower Kit covers 1.25 to 4 inches, so both reach a proper St. Augustine height. Compare grasses in the mowing height chart, and see the best self-propelled lawn mowers for thick turf.
How much fertilizer does St. Augustinegrass need?
Plan on 2 to 5 pounds of nitrogen per 1,000 square feet per year in feedings of no more than 1 pound each, all during the warm months. Sandy coastal soils leach nitrogen quickly, which is why the range runs higher than zoysia, but the top of the range belongs to irrigated lawns on poor sand. Stop feeding nitrogen four to six weeks before the first expected frost.
A slow-release such as the Milorganite Slow-Release Nitrogen 6-4-0 Fertilizer, 5 lb Bag (4-Pack) suits sandy soil because it feeds gradually instead of flushing through, and the iron greens the lawn without a growth surge. Spread with a broadcast unit like the Scotts Turf Builder EdgeGuard DLX Broadcast Spreader. Yellowing between the veins on new leaves is often an iron shortage on high-pH sand rather than a nitrogen shortage, so test before adding more nitrogen.
What kills St. Augustine grass?
Three things account for most dead St. Augustine lawns. The southern chinch bug sucks sap and kills expanding patches in hot, sunny, dry spots, often along driveways and south walls. Take-all root rot and gray leaf spot show up in wet, humid stretches. Cold is the third: St. Augustine is the least cold hardy common lawn grass and can be killed outright by a hard freeze north of its range.
The fourth cause is the homeowner. Many common lawn herbicides injure or kill St. Augustine, and the label is where you find out. The Ortho WeedClear Weed Killer for Lawns Concentrate, 1 gal label excludes Floratam St. Augustine, and the Scotts Turf Builder Weed and Feed5, 33.95 lb label excludes St. Augustine entirely. Products labeled for this grass, such as atrazine formulations, exist but carry their own restrictions. Read the weed killer safety guide before spraying anything on this lawn.
What gear fits a St. Augustine lawn?
A mower that holds 4 inches, gentle feeding, and irrigation for sandy soil that dries fast. More watering options: the best lawn sprinklers.
EGO POWER+ LM2135SP 21 in. Select Cut Self-Propelled Mower Kit
$749.00A battery self-propelled mower with a 1 to 4 inch range and a 7.5Ah battery rated for up to 60 minutes, enough for the high cut this grass needs.
Best for: St. Augustine lawns up to about half an acre
Check price on Amazon
SodPods St. Augustine Seville Grass Plugs, 64 Count
$109.98Farm-grown 3 by 3 inch Seville plugs in eight trays of eight, listed as covering 144 sq ft at 18 inch spacing once mature; it cannot ship to CA or AZ.
Best for: patching thin or damaged areas
Check price on Amazon
Milorganite Slow-Release Nitrogen 6-4-0 Fertilizer, 5 lb Bag (4-Pack)
$40.99A low-salt slow-release 6-4-0 with non-staining iron that the maker says feeds for 8 to 10 weeks, which suits leaching coastal sand.
Best for: gentle feeding without a growth surge
Check price on Amazon
Rachio Smart Hose Timer Bundle, 2 Valves plus WiFi Hub
$149.00Two app-controlled faucet valves and a hub with rain skips and flow alerts, expandable to eight valves, for yards without in-ground pipe.
Best for: automating water on sandy soil
Check price on Amazon
MySoil Soil Test Kit
$34.26A prepaid mail-in lab test reporting pH and 13 plant-available nutrients in 6 to 8 days, which separates an iron problem from a nitrogen problem.
Best for: high-pH coastal soil
Check price on AmazonHow we chose
We did not test these products in person. Picks are researched from manufacturer specifications and owner manuals, engine and safety certifications where they apply, warranty terms, public recall records, and the recurring themes in verified owner reviews. We favor established brands with large review counts and parts support, match each pick to a real yard size or task, and place it in the tier where its price and capability actually belong.
Frequently asked questions
Can you grow St. Augustine grass from seed?
No, not in any practical way. The cultivars sold for lawns, including Floratam, Palmetto and Raleigh, produce little or no viable seed, so St. Augustine lawns are established from sod or plugs. Any product advertised as St. Augustine seed deserves close scrutiny of the label, since it is often a different species entirely. Budget for sod on a new lawn and plugs for patching.
How much shade can St. Augustinegrass take?
It is the most shade-tolerant warm-season lawn grass and generally holds up on roughly four to six hours of direct sun or bright filtered light. Shade-selected cultivars such as Palmetto and Seville are the usual picks under trees. Even so, mow at the top of the range in shade, cut back on nitrogen and keep foot traffic off, because shaded stolons are thin and tear easily.
What do chinch bug damage patches look like?
Southern chinch bug damage shows as expanding yellow patches that turn straw-brown, usually in the hottest, sunniest, driest parts of the lawn such as along driveways and south-facing walls. The damage looks like drought stress but does not recover after watering. Part the grass at the edge of a patch and look at the soil surface for small black and white insects moving in the thatch.
Why did my weed and feed kill my St. Augustine grass?
Several common lawn herbicides injure St. Augustinegrass, and the product label is where that restriction appears. Some broadleaf concentrates exclude Floratam specifically, and some granular weed and feed products exclude St. Augustine entirely. Always match the label to your grass before buying, apply at the labeled rate, keep kids and pets off until dry, and never spray in wind or before rain.
Researched, not professional advice. This page is compiled from published specifications, manuals, labels and owner-review consensus, not hands-on testing. Follow the manufacturer's instructions and product label, and consult a qualified professional where safety, chemicals, fuel or structures are involved. As an Amazon Associate we earn from qualifying purchases.