When should I put down pre-emergent in St. Petersburg?

In St. Petersburg (Zone 9b), apply pre-emergent herbicide in late February when soil temperatures reach 55°F. This prevents dollarweed and other summer annual weeds from germinating. A second application in early fall (September) helps control winter annuals like Poa annua.

What's the best grass type for St. Petersburg?

St. Petersburg homeowners typically choose from St. Augustine, Bermuda, Zoysia. St. Augustine is the most popular choice because it handles St. Petersburg's summer heat well and requires less water than alternatives. Your choice may also depend on sun exposure, watering restrictions, and how much winter color matters to you.

How often should I water my lawn in St. Petersburg?

St. Petersburg's sandy soil drains quickly, so water 2-3 times per week with shorter run times. Apply fertilizer in smaller, more frequent doses to prevent nutrients from leaching through. St. Petersburg receives 52 inches of rain annually, with summer highs around 95°F. Reduce irrigation after rain and increase during dry spells.

How do I deal with chinch bugs in St. Petersburg?

Chinch bugs are most active in sunny areas during hot, dry weather. Look for irregular yellow patches that spread outward. Inspect by parting the grass at the edge of damaged areas — you'll see tiny black-and-white bugs. Apply bifenthrin or carbaryl-based insecticides when activity is spotted.

When can I plant new st. augustine in St. Petersburg?

The best time to plant st. augustine in St. Petersburg is late spring (May-June) when soil temperatures are consistently above 65°F. This gives the grass the entire growing season to establish before winter dormancy. Avoid planting after August — the grass won't have time to develop strong roots before dormancy.

Home/Lawn Care/Florida/St. Petersburg

Lawn Care Plan for St. Petersburg, FL

Climate Zone

Season

March–November

Annual Rain

52″/yr

Summer High

95°F

Lawn Care in St. Petersburg

St. Petersburg enjoys a coastal climate moderated by Tampa Bay. The peninsula location means salt tolerance matters for lawns near the water. St. Augustine handles the humidity and occasional salt exposure well. The sunny climate supports healthy turf growth, but irrigation is essential during the dry winter and spring months.

Common Grass Types in St. Petersburg

Lawns in St. Petersburg typically grow St. Augustine, Bermuda and Zoysia. Each type has different mowing heights, watering needs, and fertilizer schedules — select yours below for a tailored plan.

Select your grass type

Your schedule updates based on what's growing in your yard. Pick your grass and we'll show you exactly what to do each month.

Watering Your Lawn in St. Petersburg

Local restrictions: St. Petersburg falls under water management district rules limiting irrigation to two days per week year-round. Watering is prohibited 10am-4pm. Rain sensors are required on irrigation systems.

Soil considerations: St. Petersburg's sandy soil drains rapidly, often within hours. Water and nutrients pass through the root zone quickly, requiring more frequent but lighter applications of both. Sandy soil doesn't hold water long, so shorter, more frequent watering cycles work better than deep, infrequent irrigation.

Seasonal patterns: St. Petersburg receives 52 inches of rain annually, with a distinct rainy season. During wet months, reduce or pause irrigation entirely. Outside the rainy season, supplemental watering becomes essential as dry periods can last several weeks.

Recommended frequency for St. Augustine: 2-3 times per week during active growth, reduce in cooler months

Watering depth: 0.5-0.75 inches per session (1-1.5 inches total per week)

St. Augustine has shallow roots and needs more consistent moisture than bermuda. Sandy Florida soils may need up to 2 inches per week. Water early morning only to reduce disease pressure.

Weeds & Pests for St. Augustine in St. Petersburg

Common Weeds

NutsedgeMay–Oct
CrabgrassApr–Oct
DoveweedJun–Sep
DollarweedApr–Oct
Poa annuaOct–Apr

Common Pests

Chinch BugsJun–Aug
Sod WebwormsApr–Oct
Mole CricketsMar–Nov
White GrubsJun–Oct
ArmywormsAug–Oct

Month-by-Month St. Augustine Schedule for St. Petersburg

Here's what to do each month to keep your st. augustine lawn healthy in Zone 9b.

Month	Key Tasks
Jan	•Monitor for winter weeds (Poa annua, henbit, chickweed) •Keep mower blades sharp for clean cuts •Avoid foot traffic on frost-stressed turf St. Augustine may stay green in Zone 9b-10 but grows very slowly. Do NOT fertilize — nitrogen pushes weak growth before the grass can use it.
Feb	•Apply pre-emergent for crabgrass when soil approaches 55°F •Apply pre-emergent for broadleaf/sedge at 65°F soil temp •DO NOT scalp — maintain at 3.5-4" year-round St. Augustine has TWO pre-emergent windows: crabgrass at 55°F and broadleaf weeds/sedge at 65°F. Do NOT scalp St. Augustine like you would bermuda.
Mar	•First nitrogen application (0.5 lb N/1K sqft) once actively growing •Resume mowing at 3.5-4" every 7-10 days •Spot-treat broadleaf weeds with Celsius WG per label, NOT 2,4-D CAUTION: 2,4-D can damage St. Augustine, especially during green-up and in hot weather. Use Celsius WG per label instead — it is labeled for St. Augustine including Floratam. Do NOT reach for atrazine: Floratam is not tolerant of atrazine (Texas A&M EHT-144).
Apr	•Mow every 5-7 days at 3.5-4" •Second nitrogen application (0.5-1 lb N/1K sqft) •Begin chinch bug scouting in sunny areas •Apply preventive grub control (imidacloprid) Chinch bugs are the #1 St. Augustine pest. Scout sunny, drought-stressed areas first — that's where they start. Use the float test: cut both ends off a coffee can, push into soil, fill with water, watch for small black-and-white insects.
May	•Mow every 5-7 days at 3.5-4" •Begin deep watering schedule (1-1.5" per week) •Treat nutsedge with Sedgehammer or sulfentrazone •Plug or sod bare spots — warm soil ensures fast establishment Active growth season. St. Augustine fills gaps via stolons (above-ground runners). This is the best time for repair work with plugs or sod.
Jun	•Maintain mowing at 3.5-4" every 5-7 days •Water deeply 2-3 times per week (early morning only) •Peak chinch bug season — scout weekly in sunny areas •Apply iron supplement for color without excessive growth Peak chinch bug pressure June-August. Yellowing patches in sunny areas that don't respond to watering are likely chinch bug damage, not drought. Treat with bifenthrin.
Jul	•Continue mowing at 3.5-4" •Light nitrogen or iron-only application for color •Watch for gray leaf spot (diamond-shaped lesions on blades) •Deep, infrequent watering Gray leaf spot peaks in hot, humid weather. Avoid nitrogen during active gray leaf spot — it feeds the fungus. Use iron for color instead.
Aug	•Continue summer mowing routine •Apply fall pre-emergent for winter weeds •Scout for sod webworms (ragged-edged blades, moths at dusk) Fall pre-emergent prevents Poa annua and winter broadleaves. Apply 2-3 weeks before soil temps drop below 70°F.
Sep	•Apply potassium (0-0-50 or 0-0-62) for winter hardiness •Final nitrogen application of the season •Reduce mowing frequency as growth slows Potassium strengthens cell walls for winter. Stop nitrogen after this month — late nitrogen promotes disease-prone growth going into dormancy.
Oct	•Reduce mowing to every 10-14 days •Watch for large patch (brown patch) — circular patches of brown grass •Leaf removal — don't let debris smother stolons Large patch (Rhizoctonia) activates in fall when temps drop below 80°F. Look for circular brown areas with a yellow/orange border. Preventive fungicide (azoxystrobin) if history of disease.
Nov	•Clear leaves and debris •Monitor for winter weeds — spot-treat if needed St. Augustine slows significantly. Minimize traffic on the lawn. Do not fertilize.
Dec	•Equipment maintenance and blade sharpening •Soil test and plan spring fertilizer program Off-season planning. Soil test results take 2-3 weeks — send now to have data before spring green-up.

Active growing season Dormant/off-season

Common Questions About St. Augustine in St. Petersburg

Should I scalp my St. Augustine lawn in spring?

No — never scalp St. Augustine. Unlike bermuda, St. Augustine does not recover well from scalping. Maintain a consistent mowing height of 3.5-4 inches year-round. The crown (growing point) sits higher on St. Augustine, so cutting too low can kill the plant.

How do I identify and treat chinch bugs?

Chinch bugs are the #1 St. Augustine pest. Look for yellowing patches in sunny, drought-stressed areas that don't green up with watering. Use the float test: push a coffee can (both ends removed) into the soil at the edge of a damaged area, fill with water, and watch for small black-and-white insects floating up. Treat with bifenthrin.

Why is 2,4-D dangerous for St. Augustine?

2,4-D can cause severe damage to St. Augustine, especially during spring green-up and when temperatures exceed 85°F. Use Celsius WG per label instead — it is labeled for St. Augustine including Floratam. Do NOT substitute atrazine: Floratam is not tolerant of atrazine (Texas A&M EHT-144). If you must use a three-way broadleaf product, apply at the lowest labeled rate during cooler parts of the day.

How much should I fertilize St. Augustine?

UF/IFAS recommends 2-4 pounds of nitrogen per 1,000 square feet per year for North Florida, 2-5 pounds for Central Florida, and 4-6 pounds for South Florida. Apply in 4-6 split applications during the growing season. Use a 2:1 or 1:1 nitrogen-to-potassium ratio. Iron supplements add color without excessive growth.

What causes large brown circles in my St. Augustine lawn?

Circular brown patches are likely large patch (brown patch) disease caused by Rhizoctonia fungus. It activates in fall when temperatures drop below 80°F and in spring. Look for a yellow or orange border at the edge of the patch. Preventive fungicide (azoxystrobin) applied in September and March is more effective than curative treatment.

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Soil Conditions in St. Petersburg

The predominant soil type in St. Petersburg is sandy. Soil type affects how you water, fertilize, and maintain your lawn. Clay soils hold moisture but compact easily and need regular aeration. Sandy soils drain fast but lose nutrients quickly, requiring more frequent lighter fertilizer applications.

Zone 9b Growing Season

In USDA Zone 9b, the active growing season runs from March through November. St. Petersburg averages 52 inches of rain per year with summer highs around 95°F. Your lawn care plan is built around these local conditions — pre-emergent, fertilizer, and weed control are all scheduled so you know exactly when to act.

The St. Petersburg Challenge

Salt exposure near coastal areas

Your free Lawn HQ plan factors in St. Petersburg's specific soil, climate, and pest pressures to give you a schedule that actually works for where you live — not a generic plan that ignores local conditions.

Grass guides for St. Petersburg

Care guides for the grass types most homeowners grow in Florida.

Bermuda Grass Zoysia Grass St. Augustine Grass Centipede Grass

More for St. Petersburg homeowners

Go deeper on the grass you grow, the products you use, and the timing that matters in Florida.

Month-by-month St. Augustine Grass care calendar

Every task, every month — fertilizer, mowing, pre-emergent, and pest watch for St. Augustine Grass lawns.

Open the St. Augustine Grass calendar

St. Augustine Grass pre-emergent application timing — full guide

What to do this month for your st. augustine grass lawn.

October in St. Petersburg

What to do this month

Check if a herbicide is safe for your grass

Match products to St. Augustine Grass before you spray — no more guessing at the label.

Calculate your spreader settings

Dial in the right setting for your spreader and bag — every product, every coverage rate.

Measure your yard size from satellite

Map your lawn from above so your application rates are right the first time.

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