Most St. Augustine grass maintenance calendars you’ll find online were written for Texas, the Carolinas, or “Florida” in general. None of them account for the one rule that defines lawn care in Pinellas County: you cannot apply nitrogen or phosphorus fertilizer from June 1 through September 30. That single ordinance reshuffles the entire fertilizing schedule, and it’s why generic calendars fail St. Pete homeowners.
This calendar is built specifically for St. Petersburg and Pinellas County’s subtropical climate, using University of Florida IFAS Extension guidance for central Florida, aligned with the Pinellas County fertilizer ordinance. Print it, stick it on the fridge, and follow it month by month.
Short on time? St. Pete Lawncare runs this exact schedule for hundreds of Pinellas County lawns. Get a free estimate and we’ll handle the calendar for you.
The month-by-month St. Augustine calendar
| Month | Mowing | Watering | Fertilizing | Watch for |
|---|---|---|---|---|
| January | As needed, 3.5–4” | Only if dry (~every 10–14 days) | None | Large patch in cool, wet spells |
| February | Resume regular mowing | Increase slightly | Pre-emergent herbicide ~Feb 15 | Crabgrass germination |
| March | Weekly, 3.5–4” | ~2x/week if no rain | Soil test; prep for spring feed | Chinch bugs in sunny spots |
| April | Weekly | 2x/week | First N application (early April) | Chinch bugs, weeds |
| May | Weekly | 2x/week | Last N/P application before ban (mid-late May) | Chinch bugs peak, gray leaf spot |
| June–Sept | Weekly, keep at 4” | Rain usually covers it; water only in dry spells | FERTILIZER BAN — no N/P. Iron only if yellowing | Chinch bugs, gray leaf spot, tropical storm stress |
| October | Weekly → tapering | Reduce as rain tapers | First post-ban feed (early Oct) | Large patch as nights cool |
| November | Every 10–14 days | As needed | Optional light feed early Nov | Large patch |
| December | As needed | Only if dry | None | Frost damage (rare), brown dormant patches |
Mowing heights and rates below come from UF/IFAS Extension publications ENH5/LH010, St. Augustinegrass for Florida Lawns and ENH-73, Yearly Calendar for St. Augustinegrass Care and Culture. Pinellas County falls in UF/IFAS’s “central Florida” region (south of Ocala to a line from Vero Beach to Tampa).
January & February: semi-dormant season
St. Augustine grass in Pinellas County rarely goes fully dormant, but growth slows to a crawl. Mow only as needed, sometimes just once or twice a month, and keep the deck at 3.5 to 4 inches for standard cultivars like Floratam, Bitterblue, and Classic (2 to 2.5 inches for dwarf varieties like Seville), per UF/IFAS.
Water only if the lawn shows drought stress: blades folding, a blue-gray tint, or footprints that linger. That’s typically every 10 to 14 days in a dry winter. When you do water, apply about 3/4 inch per session, enough to wet the top 8 to 12 inches of the root zone, according to UF/IFAS irrigation guidance.
Don’t fertilize. The grass can’t use it, and it feeds winter weeds instead.
Mid-February (around Feb 15 for central Florida): if crabgrass was a problem last year, this is your pre-emergent herbicide window. Timing matters, since pre-emergents only work before seeds germinate.
Watch for: large patch (a Rhizoctonia disease) during cool, wet stretches. It shows up as circular yellow-brown patches that can expand fast in overwatered lawns.
March: green-up month
Daytime highs back in the 80s mean your lawn is waking up. Resume weekly mowing at 3.5 to 4 inches, and never remove more than one-third of the blade in a single cut. Sharpen your mower blade now. St. Augustine’s coarse blades shred on dull edges, and shredded tips invite disease.
This is a good month to pull a soil test through the Pinellas County Extension office before you spend money on fertilizer. Under county rules, you actually need a soil test showing deficiency before applying phosphorus at all.
Increase watering to roughly twice a week if rain is scarce, still 3/4 inch per session.
Watch for: the first chinch bug activity in hot, sunny areas near driveways and sidewalks. Do the coffee-can test: cut both ends out of a can, push it into the turf at the edge of a yellowing patch, fill it with water, and see if chinch bugs float up.
April: when to fertilize St. Augustine grass in Florida
Early April is UF/IFAS’s recommended first fertilizer application for central Florida, and in Pinellas County it’s your most important feeding of the year, because the window closes June 1.
Apply 1 pound of nitrogen per 1,000 square feet using a fertilizer with at least 65% slow-release nitrogen (the Florida Urban Turf Fertilization Rule allows up to 2 lbs per 1,000 sq ft when using 65%+ controlled-release N). Sweep any granules off driveways and sidewalks back into the lawn. That’s not just good practice, it’s county ordinance.
Mowing is weekly now. Watering runs about twice a week, adjusting for rain. Our professional mowing service follows this exact height and frequency.
Watch for: chinch bugs ramping up, and broadleaf weeds taking advantage of thin spots. Post-emergent broadleaf herbicides (like atrazine) work well now, but stop using them once temperatures consistently exceed 85°F. They can injure St. Augustine, especially Floratam.
May: last call before the ban
Mid-to-late May is your final nitrogen and phosphorus application until October. If your lawn needs it, apply up to 1 pound of N per 1,000 square feet by the last week of May. Don’t cut it close to June 1. A heavy rain right after application washes your money into Tampa Bay and feeds algae blooms, which is exactly what the Pinellas County fertilizer ban exists to prevent.
May is peak chinch bug season in Pinellas. The southern chinch bug is the number one insect pest of St. Augustine grass, and damage shows up first as yellowish-brown patches in full sun, often near pavement. Check weekly.
Watch for: gray leaf spot (Pyricularia grisea). It thrives when turf is over-fertilized and over-watered heading into summer. If you see oblong gray-brown spots on blades, back off the water and skip that second feeding. A targeted weed control program can also help keep stressed turf from being overtaken.
June–September: the Pinellas County fertilizer ban
From June 1 to September 30, Pinellas County prohibits the sale and use of any lawn or landscape fertilizer containing nitrogen or phosphorus (pinellas.gov, stpete.org). Yes, it applies to homeowners, not just professionals. For the full rules, exemptions, and what happens if you ignore them, read our guide to the St. Pete fertilizer ban.
The good news: your lawn barely misses it. Summer is rainy season, and St. Augustine grows aggressively on rainfall alone. Your job for four months is simple:
- Mow weekly at 4 inches. Taller grass shades roots, crowds out weeds, and handles summer stress better. Raise the deck, don’t lower it.
- Water only during dry spells. Most weeks, afternoon thunderstorms cover it. Overwatering in summer is the fast track to gray leaf spot and root rot. If you irrigate, run in the early morning, never evening.
- If the lawn yellows, use iron instead of nitrogen. Iron and micronutrient products are allowed during the ban and green up the lawn without pushing the soft, disease-prone growth nitrogen causes. UF/IFAS notes foliar iron (ferrous sulfate or chelated iron) corrects iron-deficiency yellowing. Our fertilization program uses ban-compliant iron and micronutrient blends to keep lawns green all summer.
- Keep the 10-foot fertilizer-free zone near seawalls and water bodies year-round. It matters even more when canals and the Bay are warmest.
Watch for: chinch bugs during any hot, dry break between storms; gray leaf spot after stretches of daily rain; and sod webworms (look for ragged blade edges and small moths flying up at dusk).
October: feeding window reopens
The ban lifts September 30. Early October is your third and often final feeding of the year: 1 pound of N per 1,000 square feet, ideally with potassium (something like a 15-0-15), which helps the lawn harden off for winter without pushing tender top growth.
Rain tapers off this month, so shift irrigation back to an as-needed schedule, roughly once or twice a week, 3/4 inch per session.
Mowing stays weekly early in the month, then stretches out as growth slows.
Watch for: large patch disease as nights drop into the 60s and soil stays moist. Reduce watering at the first sign of expanding yellow-brown rings.
November & December: wind-down
Growth slows sharply. Mow every 10 to 14 days, then only as needed. Water only during dry stretches. Pinellas winters are dry season, but cool temperatures mean low evaporation, so every 10 to 14 days is usually plenty.
An optional light application in early November works for high-maintenance lawns, but most Pinellas St. Augustine lawns do fine with three feedings a year (April, May, October). UF/IFAS’s annual nitrogen guideline for central Florida is 2 to 5 pounds per 1,000 square feet; Pinellas County caps it at 4 pounds per 1,000 square feet per year. Staying at 2 to 3 pounds total keeps you legal and under budget, with less disease pressure.
Watch for: the occasional frost advisory in December or January (rare but not impossible). Don’t mow frost-damaged grass until it dries out, and don’t try to “fix” winter browning with fertilizer. It’s normal dormancy behavior, even this far south.
St. Augustine grass mowing height and year-round rules
- Mow high. 3.5 to 4 inches for standard cultivars, always. UF/IFAS is blunt about this: scalping St. Augustine stresses the lawn, shallow-roots it, and opens the door to pests. It’s the single cheapest thing you can do right.
- Water deep and rare. 3/4 inch per session, only when the lawn asks for it. Daily shallow watering grows shallow roots and fungus. If your system needs adjusting, see our irrigation services.
- Feed three times, not six. April, May, October. Three slow-release feedings inside the legal windows beat six rushed ones.
- Scout monthly. Five minutes with a coffee can and a walk around the yard catches chinch bugs and disease while they’re still cheap to fix.
St. Augustine grass care FAQ
How often should you mow St. Augustine grass in Florida?
Weekly during the growing season (roughly March through October) and every 10 to 14 days in winter, per UF/IFAS. Keep standard cultivars at 3.5 to 4 inches and never remove more than one-third of the blade in a single mowing.
When can I fertilize my lawn in Pinellas County?
Anytime except June 1 through September 30, when nitrogen and phosphorus fertilizers are banned county-wide. For St. Augustine grass, the sweet spots are early April, mid-to-late May, and early October. Iron and micronutrient products (no N or P) are allowed year-round.
How much should I water St. Augustine grass in St. Petersburg?
About 3/4 inch per session, only when the lawn shows drought stress (folded blades, blue-gray tint, lingering footprints). That works out to every 3 to 4 days in late spring, rarely at all during the summer rainy season, and every 10 to 14 days in winter.
Why is my St. Augustine grass turning yellow in summer?
During the June–September ban months, yellowing is usually iron deficiency or gray leaf spot, not nitrogen hunger. Apply a foliar iron product (ban-compliant) and check that you’re not overwatering. If yellow patches appear in full sun near pavement, test for chinch bugs first.
What kills St. Augustine grass in Florida?
The big four: chinch bugs (the #1 insect pest), gray leaf spot and large patch (fungal diseases fueled by overwatering and over-fertilizing), take-all root rot, and scalping the lawn by mowing too short. Almost all of them trace back to cultural mistakes, which is exactly what a maintenance calendar prevents.
The shortcut: let us run the calendar for you
Everything above is exactly what St. Pete Lawncare’s lawn care program does on autopilot: mowing at the right height every visit, ban-compliant fertilization timed to the April/May/October windows, and monthly pest and disease scouting by crews who know what chinch bug damage looks like in a St. Pete lawn (not a Texas one).
Get your free lawn care estimate or call (727) 218-4044. We’ll build the plan around your grass, your soil, and Pinellas County’s rules.
Wondering what professional lawn care runs? See our breakdown of lawn care costs in St. Pete.
Sources: UF/IFAS ENH5/LH010 — St. Augustinegrass for Florida Lawns · UF/IFAS ENH-73 — Yearly Calendar for St. Augustinegrass Care and Culture · Pinellas County Fertilizer & Landscape Information · City of St. Petersburg — Fertilizer Ban Starts June 1