St. Augustine grass is a popular choice for Florida homeowners, valued for its dense, carpet-like growth and tolerance for the state’s intense summer heat. It spreads quickly by above-ground runners, known as stolons, establishing a thick turf cover that naturally suppresses many weeds. Maintaining this warm-season grass requires specific attention to Florida’s unique challenges, including high humidity, sandy soils that struggle to retain nutrients, and prolonged intense sun. Proper care techniques must be adapted to these conditions to ensure the lawn remains healthy and resilient.
Proper Irrigation Practices for Florida’s Climate
Deep, infrequent watering is superior to daily, shallow sprinklings for St. Augustine grass. Applying water less often but for longer durations encourages the roots to grow deeper, increasing drought tolerance. Aim for \(1/2\) to \(3/4\) inch of water per application to moisten the top six to eight inches of the root zone.
The best time to irrigate is early morning (4 a.m. to 10 a.m.) to minimize water loss to evaporation and allow blades to dry quickly. Wet turf remaining overnight favors fungal diseases, a common problem in Florida’s humid climate. Seasonal adjustments are necessary; weekly watering is often sufficient in cooler months, but summer heat may require two or more deep waterings per week, adhering to local restrictions.
Essential Mowing Techniques and Heights
Setting the mower deck to the correct height is essential for a St. Augustine lawn. The optimal mowing height is between \(3.5\) and \(4\) inches for standard varieties like Floratam. This taller height allows the blades to shade the soil, keeping the root zone cooler and suppressing weed germination.
Follow the “one-third rule,” removing no more than one-third of the grass blade length per mowing. If the grass is maintained at 4 inches, mow before it reaches 6 inches, which may require mowing every five to seven days during peak summer. Keeping the mower blade sharp is important; a dull blade tears the grass, making the turf susceptible to disease and insect entry.
Seasonal Fertilization Schedule
St. Augustine grass requires regular nutrients during its active growing season, from early spring through early fall. The first application should occur in early spring (March or April), once the lawn has fully greened up and the danger of frost has passed. Use a slow-release nitrogen fertilizer for this initial feeding to provide a steady supply of nutrients without causing excessive, weak growth.
Subsequent applications are spaced every six to eight weeks, but homeowners must adhere to local ordinances. Many areas implement a summer blackout period (June through September) restricting nitrogen and phosphorus fertilizers. During this period, a supplemental iron product is beneficial. Iron enhances the lawn’s green color without promoting rapid shoot growth that can exacerbate pest and disease issues. The final application in early fall (September or October) should focus on a high-potassium formula to help the grass store energy and improve hardiness against stress and disease.
Identifying and Treating Common Florida Pests and Diseases
Two destructive threats to St. Augustine grass are the Southern Chinch Bug and the fungal disease Brown Patch. Chinch bugs are tiny insects that suck sap and inject a toxin, causing the grass to turn yellow, then reddish-brown, and eventually die. Damage often appears first in hot, dry areas, such as along driveways and sidewalks, and dead patches will not recover with watering alone.
If chinch bugs are confirmed by checking the border between dead and healthy grass for the small, black-and-white adults or reddish nymphs, a targeted application of a contact insecticide, such as bifenthrin, is necessary.
Brown Patch appears as circular or irregular brown patches ranging from a few inches to several feet in diameter. This disease is most active in the spring and fall when temperatures are between \(65^{\circ}\text{F}\) and \(80^{\circ}\text{F}\) and prolonged leaf wetness is present. A distinguishing feature is that the leaf blades within the patch may be easily pulled from the runner, showing a dark, rotted area at the base.
Correcting cultural practices, such as reducing excessive nitrogen in the fall and ensuring morning-only irrigation, is the first step in managing the disease. If the disease is severe, a curative fungicide containing active ingredients like propiconazole or azoxystrobin can be applied to stop the spread.