How Often to Mow St. Augustine Grass: The North Florida Cadence

Weekly vs bi-weekly: the North Florida cadence

From roughly March through October, healthy St. Augustine grass in St. Johns County needs a weekly cut to stay within the one-third rule (covered below). In hot, wet summers it can push out 2–3 inches of new growth per week, especially if irrigated and fertilized properly.

From November through February the grass slows down significantly. Most yards can move to a bi-weekly cadence during this window without losing quality. Some properties go every 3 weeks in deep January. Watch the grass — if it's not growing, don't cut it just because it's time on the calendar.

The correct cutting height

The single biggest mistake homeowners make with St. Augustine grass is cutting too short. The recommended height range is 3.5 to 4 inches. Some landscapers cut shorter because it looks tidy for a day or two, but the lawn pays for it: weaker root development, more weed pressure, faster drying, more heat stress.

Our standard setting on a Florida St. Augustine yard is 4 inches. That height produces:

• A denser canopy that shades out weed seeds before they germinate.
• Better moisture retention — taller grass shades the soil and reduces evaporation.
• Deeper roots, since blade height and root depth are correlated.
• Less visible stress during summer heat peaks.

The one-third rule

Never cut off more than one-third of the total blade height in a single pass. If your lawn is at 6 inches and you cut down to 4, that's a 33% cut — borderline OK. If you cut down to 3, that's a 50% cut, and the grass will brown, stress, and need 10–14 days to recover.

The one-third rule is why weekly mowing matters in summer. If you skip a week during peak growth and your grass gets to 7 inches, dropping it back to 4 in a single cut violates the rule and damages the lawn. The correct fix after missing a week is either raise the deck for one cut and then come down the next week, or accept the stress and keep mowing height at 4.

Why sharp blades matter

Dull mower blades tear grass rather than cutting it cleanly. Torn blades dry out and turn brown at the tips within 24–48 hours, giving the lawn an overall hazy-brown look even when it's otherwise healthy. Torn edges also create entry points for fungal diseases like brown patch.

Our crews sharpen blades on a schedule. For DIY mowing, plan to sharpen at least twice per season on a residential mower. Signs blades are dull: brown tips showing the day after mowing, frayed rather than clean-cut grass edges when inspected closely.

Mowing patterns

Alternate mowing direction each week. If you mow north-to-south this week, mow east-to-west next week, then diagonal, then the other diagonal. This does three things: prevents the grass from developing a grain (leaning in one direction), prevents ruts from mower tires in the same tracks week after week, and creates the subtle striping you see on professional lawns.

Seasonal adjustments

Summer (peak heat, July–August): consider raising the deck to 4.5 inches to retain moisture. Rainy season (June–October): prioritize mowing when grass is dry to avoid clumping and fungal spread. Fall (October–November): continue at 4 inches until growth slows. Winter (December–February): 4 inches still works; mow only when grass is visibly taller than 3 inches.

Hiring a pro vs doing it yourself

DIY mowing works for small, flat yards with no major trim requirements. Most St. Johns County homeowners hire a crew because: weekly schedules fit around work and travel, consistent crew produces a cleaner edge line than a rotating DIY effort, professional equipment cuts faster and cleaner, and you don't have to store, service, or haul a mower. Professional crews also scout for pest and fungus issues during each visit — something DIY mowing misses.

How this applies to your St. Augustine yard

Every piece of advice above has to be filtered through the reality of North Florida — USDA hardiness zone 9a, humid subtropical climate, sandy coastal soils, a long growing season, and an Atlantic hurricane season that runs June through November. A tactic that works in Atlanta or Dallas often falls apart in St. Johns County because the climate is genuinely different. The calendar works differently, the grass species work differently, the pests work differently, and the irrigation needs are wildly different from inland Southern lawns.

On the coast — St. Augustine Beach, Vilano Beach, Anastasia Island, Crescent Beach — salt-laden air is a factor that inland yards never deal with. Salt tolerance matters for every plant selection. West of I-95 in the master-planned communities (World Golf Village, Palencia, TrailMark, Shearwater, SilverLeaf, Murabella, Beacon Lake, Nocatee) the big factor is HOA standards and tree canopy from mature oaks and pines. In older St. Augustine and St. Augustine Shores, live oak canopy and established beds create their own micro-conditions. One size does not fit all across the 15-mile service radius we work inside.

Why a local St. Johns County crew matters

There is a real gap between a national or regional lawn company running generic playbooks and a local St. Augustine crew that knows which streets flood first in a summer downpour, which HOA in Palencia wants dark brown mulch versus which section of Nocatee approves pine straw, and which homes on Anastasia Island have well-water irrigation that stains driveways if the heads are misaimed. That local knowledge is the difference between a yard that looks okay and a yard that looks genuinely cared for.

Lawnshark Landscaping Inc. is based in St. Augustine, FL. Our trucks park here, our crews live here, and our 15-mile service radius is strict so we can actually run a tight schedule. We are fully licensed and insured, and certificates of insurance are emailed directly to HOA property managers before the first visit on any HOA property. That single detail removes a lot of friction for homeowners in World Golf Village, Palencia, Beacon Lake, Nocatee, SilverLeaf, Murabella, TrailMark, and Shearwater.

Related services worth combining

Most questions about lawn care overlap with other services. Weekly lawn maintenance pairs naturally with quarterly mulch and pine straw refresh, semiannual palm tree trimming, and an annual irrigation audit. Sod installations almost always make more sense when combined with a full bed refresh and an irrigation tune-up because a new lawn is only as good as the water delivery behind it. Hardscape projects (paver patios, walkways, retaining walls) usually trigger a landscape design refresh on the surrounding beds because newly finished hardscape highlights every tired planting it sits next to.

We run all nine of our services under one crew with one invoice, which means you are not juggling three contractors who each blame the others when something slips. One call, one accountable team. If you want to bundle we will quote it as a single flat rate — a common bundle for a St. Johns County home is weekly lawn maintenance, quarterly mulch refresh, and palm trim twice a year, which is enough to keep a property at HOA standard year round without any additional scheduling effort from you.

What a free estimate looks like

Every estimate is free, on-site, written, and flat-rated before any work begins. There are no deposits required, no trip fees, and no obligation after the quote lands in your inbox. We walk the property with you (or alone, if you prefer), measure the lawn, count the bed linear feet, identify the grass cultivar, check irrigation coverage, and note any HOA requirements for the property. The written quote typically lands in your email within 48 hours of the visit.

If you move forward, recurring services can usually start within 3–7 days of approval and we lock a fixed day of the week for your property. One-time projects (sod installs, paver patios, landscape design) are scheduled based on current queue — fall (October through February) is our fastest hardscape window because the lawn-maintenance load drops. Call 904-429-5845 or email lawnshark904@gmail.com to schedule an estimate. For snowbird, seasonal, or out-of-state owners we run photo-documented service so you have full visibility into property condition without needing to visit.

The St. Augustine seasonal calendar in plain English

Because our climate runs on a different rhythm than most of the country, it helps to have a simple month-by-month frame for how St. Johns County yards behave. January and February are cool and dormant — St. Augustine grass goes semi-dormant below 55°F and you will see color fade, which is normal, not a problem. This is the right window for hardscape work, tree trimming, bed refresh, and landscape design because the lawn is quiet. March is the wake-up: first mow of the season. A licensed chemical lawn company (not us — fertilizer and pre-emergent are a separate FDACS license) will typically want to apply pre-emergent crabgrass control and the first light fertilization once nighttime temps hold above 65°F. April and May are the strong growth window — weekly mowing, sharp blades, and the first real irrigation tune-up of the year.

June through September is the hard season. Daily afternoon storms, high humidity, and soil temperatures over 85°F create perfect conditions for chinch bugs, gray leaf spot, take-all root rot, and fungal pressure on St. Augustine grass. Mowing frequency stays weekly, sometimes every five days on irrigated lawns. Irrigation should run early morning only — never evening — to avoid leaf wetness overnight. Hurricane season is also live, so homeowners need a plan for pre-storm yard prep and post-storm debris cleanup. October and November are recovery months — a last fertilization of the year is typical before the winterizer cutoff (handled by your licensed applicator, not us), plus gutter and leaf cleanup under live oak canopy, and prepping irrigation for cooler nights. December is quiet maintenance mode.

Common mistakes we see on St. Augustine properties

A handful of mistakes show up on almost every new estimate we walk. Mowing too short is the most common — St. Augustine grass should be cut at 3.5 to 4 inches, never lower. Scalping a Floratam lawn opens the door to weeds, chinch bugs, and fungal disease within one or two mow cycles. Watering every day on a timer is the second most common error — deep, infrequent watering (roughly 3/4 inch twice a week) produces far stronger roots than daily light watering, which trains roots to stay shallow and makes the lawn fragile the first time a timer fails or a storm knocks out power.

Over-fertilizing in summer is the third — a mistake we see on estimate walkthroughs, though the fertilization itself is done by a separately licensed applicator, not by us. Heavy nitrogen applications when soil temperatures are high push fast top growth that chinch bugs and fungal disease love. Applying mulch too thick against tree trunks and plant bases (volcano mulching) is the fourth — two to three inches total is plenty, pulled back from trunks by a few inches. Ignoring irrigation coverage gaps is the fifth — most yards we audit have at least one zone with a head that has drifted, clogged, or been clipped by a mower. A thirty-minute irrigation walk once per quarter catches all of that before a brown patch appears in the wrong place.