When to Start Spring Lawn Care in Jacksonville (2026 Guide)

Spring in NE Florida Starts Earlier Than You Think

If you're from the Midwest or Northeast, you're used to waiting until April or May to think about spring lawn care. In Jacksonville, that mindset will cost you. NE Florida's spring effectively begins in late February, when daytime temperatures regularly reach the low 70s and soil temperatures start climbing toward the critical 55°F threshold that triggers weed seed germination. By the time most northern states are thawing out, Jacksonville lawns are already showing new growth and preparing for the aggressive growing season ahead.

The key to a great NE Florida lawn is front-loading your effort in February and March. Get ahead of weeds, prep your irrigation system, and assess winter damage before the heat of summer arrives. Here's exactly what to do and when.

Pre-Emergent Herbicide: Don't Miss This Window

Pre-emergent herbicide is the single most important spring lawn care step for NE Florida yards. It works by creating a chemical barrier at the soil surface that prevents weed seeds from germinating — it does not kill existing weeds. The timing is critical: apply it too early and it breaks down before weed seeds germinate; apply it too late and the weeds already have a root system it can't stop.

In Jacksonville, the target application window is mid-February to early March, when soil temperatures at a 2-inch depth reach 50–55°F. You can monitor soil temps at the University of Florida IFAS weather station network (fawn.ifas.ufl.edu). Common pre-emergent products for NE Florida lawns include pendimethalin (sold as Scotts Halts and others), prodiamine (Barricade), and dithiopyr (Dimension). All work well on crabgrass, dollarweed, and annual bluegrass.

Important caveat: if you're planning to reseed or overseed bare patches, do not apply pre-emergent — it will prevent your grass seed from germinating too.

Assessing Winter Damage

Most NE Florida winters are mild enough that St. Augustine grass stays partially green, but occasional cold snaps — particularly in northern Duval County, Nassau County, and inland Clay County — can cause patchy dormancy or cold damage. Here's how to evaluate your lawn after winter:

• Brown patches in sunny areas: May be cold damage (St. Augustine at the northern edge of its range) or chinch bug damage from the prior fall. Tug on the grass — if it pulls up easily with no roots, it's dead and needs to be resodded.
• Thin, weak growth in spring: Often indicates compacted soil or a thatch layer that accumulated over winter. Aeration in March can dramatically improve recovery.
• Yellow or light green lawn that won't green up: Could be a soil pH issue — NE Florida's sandy soils tend toward acidic. A simple soil test from your county extension office ($7 at Duval County Extension) will tell you if you need lime.

First Fertilization of the Year

Don't rush to fertilize. Applying nitrogen before your lawn is actively growing wastes the product and can push growth that the roots aren't yet strong enough to support. In Jacksonville, wait until your St. Augustine or Zoysia lawn is at least 50% green and actively growing — typically mid-March to early April, depending on the winter.

For the first application of the year, choose a slow-release nitrogen fertilizer with micronutrients. An 8-0-12 or 6-1-0 product with iron is ideal for NE Florida's sandy, sometimes iron-deficient soils. Apply at the label rate — more is not better and can burn newly emerging grass. Water it in thoroughly within 24 hours.

Remember that Duval County and St. Johns County have fertilizer blackout periods (June 1 – September 30 for most areas). Plan your spring applications to stay within the legal window and give your lawn the nutrients it needs before the summer blackout begins.

Irrigation System Startup

If you turned off your irrigation system or ran it at reduced frequency over winter, spring is the time for a thorough system check before your lawn starts demanding water. Walk each zone while it runs and look for:

• Broken or misaligned spray heads (a common casualty of lawn mowers hitting them)
• Clogged rotors that aren't rotating through their arc
• Zones that won't turn on (could be a solenoid or wiring issue)
• Heads watering sidewalks, driveways, or the street instead of your lawn
• Rain sensor function — a required device under Florida law; test it by holding a cup over it during a scheduled run to verify it shuts the system off

Adjust your controller to run 2 days per week per St. Johns Water Management District rules. A typical NE Florida spring needs about 3/4 inch per zone application, which translates to roughly 30–45 minutes for spray heads or 45–60 minutes for rotors, depending on your head spacing.

Aeration: Spring vs. Fall

Core aeration — physically pulling small plugs of soil from the ground — relieves compaction, improves drainage, and lets water and fertilizer reach the root zone more effectively. In NE Florida, the best time to aerate warm-season grasses is during the active growing season: late spring (April–May) or early fall (September). Aerating in dormancy or early spring before the lawn is actively growing can stress the grass.

For most NE Florida yards with sandy soils, aeration is less critical than in clay-heavy northern lawns, but homes with heavy foot traffic, compacted fill soils in newer developments, or thick thatch layers benefit significantly. Pair aeration with a light topdressing of sand or compost to fill the holes and further improve soil structure.

Resuming Regular Mowing

Resume your regular weekly mowing schedule once your grass is actively growing and reaches above your target height. For St. Augustine, that means mowing when the blade reaches 4.5–5 inches and cutting back to 3.5–4 inches. Never remove more than one-third of the blade in a single mowing — "scalping" in spring is one of the leading causes of thin, weedy lawns in summer.

Spring is also a great time to sharpen or replace your mower blade. A sharp blade cuts cleanly; a dull blade tears the grass, leaving ragged brown tips that invite disease. If your mower is more than a few years old, check the deck height calibration — settings shift over time.

Need a hand getting your lawn spring-ready? Find a local NE Florida lawn care pro on YardLink to schedule spring cleanup, aeration, and fertilization.