This 8-round schedule focuses on weed prevention (pre-emergent and post-emergent weed control) and fertilization. Pest control is not included in these rounds. Each round’s timing and treatments are tailored to South Florida’s climate and St. Augustine grass needs.
Round 1 (Late January – Early February)
Pre-Emergent & Early Fertilization. Apply a pre-emergent herbicide in late winter (around late Jan or early Feb) to prevent spring/summer weeds (like crabgrass, goosegrass, spurge, and oxalis) from germinating. This early timing (about February 1st) establishes a chemical barrier before weed seeds sprout. Along with weed prevention, apply a balanced, slow-release fertilizer to give the lawn a nutrient boost as it comes out of winter dormancy. South Florida’s mild winter allows for a light feeding at this time to encourage early spring green-up.
Round 2 (March – Early April)
Spring Fertilization & Weed Control. By early spring (around March), the lawn is entering active growth and ready for a feeding. Apply a spring fertilizer (high in nitrogen for growth) to strengthen the turf as temperatures rise. If using a split-application pre-emergent program, this round can include a second application of pre-emergent herbicide about 6–8 weeks after Round 1 to extend weed prevention into summer. Otherwise, focus on spot-treating any breakthrough weeds with a post-emergent herbicide labeled for warm-season turf. Broadleaf weeds that survived winter (e.g. clover or dollarweed) should be sprayed now so the lawn heads into late spring weed-free.
Round 3 (Late April – May)
Late Spring Weed Control & Feeding. Continue supporting the lawn with nutrients and keep weeds in check. Apply another round of slow-release fertilizer in late spring – this is often the second major feeding of the year. This maintains vigor as the lawn approaches the summer growth peak. At the same time, treat any remaining weeds or new weed seedlings – spot-apply post-emergent herbicides to visible broadleaf weeds or sedges so they don’t spread. A thick, well-fed St. Augustine turf will crowd out many late-spring weeds naturally.
Round 4 (June)
Early Summer Treatment. Summer is when St. Augustine grass grows fastest, so regular feeding is important. Apply a mid-summer fertilizer treatment (preferably a controlled-release formula) to nourish the lawn through the hot, rainy season without causing surge growth. By now, the pre-emergent barrier from spring may be breaking down, but new pre-emergents are not typically applied in mid-summer. Instead, continue to monitor and spot-treat any weed outbreaks. Warm-season weeds like spurge or tropical sedges can appear in early summer, so address them with appropriate herbicide spot treatments. Maintaining proper mowing and irrigation during this period also helps the fertilizer work effectively and keeps the lawn dense (which further prevents weeds).
Round 5 (July – August)
Late Summer Feeding & Weed Management. Mid-summer in South Florida is hot and humid, but St. Augustine still requires nutrients during this growing period. Provide another fertilization in mid-to-late summer (around July, roughly the third feeding of the year). Using a slow-release nitrogen source is wise this time of year to avoid fertilizer burn or disease pressure. Continue to spot-treat weeds as needed – common Florida summer weeds like dollarweed, doveweed, or kyllinga can spread with seasonal rains if not controlled. By feeding the lawn and eliminating weed competition, you help the grass stay thick and healthy through the peak of summer.
Round 6 (September)
Early Fall Fertilization & Weed Prevention. Early fall is the time for the last heavy feeding of the year in South Florida. Apply a fall fertilizer in September (often a “winterizer” formula with slightly lower nitrogen and higher potassium) to strengthen the turf’s roots as growth begins to slow. This ensures the St. Augustine grass has nutrients stored for the cooler months ahead. In late September (or early October), apply a fall pre-emergent herbicide to prevent cool-season weeds from invading. This pre-emergent targets winter annual weeds like annual bluegrass (Poa annua), chickweed, and henbit before they germinate. Be sure to water in the pre-emergent for proper activation. After this round, avoid any further high-nitrogen fertilizations so the lawn can start hardening off for winter.
Round 7 (October – Early November)
Late Fall Weed Control & Lawn Conditioning. By late fall, major fertilizations are done, but lawn care continues. This round focuses on cleaning up any remaining weeds and preparing the grass for the mild South Florida winter. Spot-treat any persistent or late-germinating weeds with post-emergent herbicides – for example, treat visible winter annuals like chickweed or lawn burweed that might sprout as temperatures cool. If a fall pre-emergent wasn’t applied yet, it can be done in early October during this round (though earlier is better). You can also apply micronutrients (like iron) in late fall to keep the grass green without forcing new growth. This helps maintain an attractive lawn going into the winter months, when growth naturally slows.
Round 8 (Late November – December)
Winter Weed Control (Optional Light Feeding). South Florida’s winter is mild, so the lawn may not go fully dormant. However, cool-weather weeds can still be a problem now. Use a broadleaf herbicide safe for St. Augustine (such as atrazine) to control winter weeds like chickweed, henbit, clover, and others that are active in the cooler season. This treatment will clean up the lawn by eliminating those weeds before they can spread seeds. Routine fertilization is not needed in winter – avoid heavy nitrogen, since the grass is growing slowly and excessive N can invite disease. If the lawn shows signs of nutrient deficiency or has lost color, you can apply a light winter fertilizer (no more than ~0.5 lb N/1000 sq. ft.) to maintain color, or use a potassium supplement to improve winter hardiness if soil tests indicate a need. Many South Florida lawns will do fine with just targeted weed control in this round, reserving any heavy feeding for the spring startup of the next growing season.
Make Your Yard the Envy of the Neighborhood
By following these eight simple rounds of fertilization and weed control, your St. Augustine lawn will stay thick, healthy, and ready to wow the neighbors—all in tune with South Florida’s unique climate. Combine this schedule with good mowing and lawn watering habits, and tweak it here and there to match your yard’s personality. And if you’d like some extra help or expert advice, Floridist has your back.
Get in touch with us, and we’ll work with you to create the lush, green lawn you’ve always wanted!