Best Time to Fertilize St. Augustine Grass in Texas
A simple, season-aware fertilization schedule for St. Augustine lawns in Southeast Texas.
The short answer
For St. Augustine in the Greater Houston area, fertilize twice a year: once in late spring (April–May) once the lawn has fully greened up, and again in early fall (September). Skip summer feedings — they push excess top growth that's vulnerable to fungal disease in our humidity.
Spring application (April–May)
Wait until the lawn is fully greened up and you've mowed at least twice — that's the signal that roots are active and the lawn can take up nutrients. A balanced slow-release fertilizer with a moderate nitrogen content is the right starting point for most homes. Water in after application.
Fall application (September)
Early fall is the second key window. The fall feeding builds root reserves heading into cooler weather and supports cold tolerance. Use a fall-formulated product with lower nitrogen and higher potassium where available.
What about summer?
Don't fertilize St. Augustine in deep summer (June–August). Excess nitrogen pushes top growth that's prone to brown patch and other fungal disease in our humidity. If the lawn looks tired in July, the answer is usually water and cut height — not fertilizer.
Common mistakes
Over-application is the most common mistake — more is not better. Always follow the bag rate. Apply to dry grass, water in after, and avoid application before heavy rain (which washes nutrients into storm drains).
Pest and weed control
Fertilization, weed control, and pest management are typically separate program decisions. Klean Kuts focuses on mowing, beds, hedges, and cleanups — for fertilization and pest programs, we partner with trusted local applicators who specialize in Texas turf.