St. Augustine grass only needs nitrogen fertilizer a handful of times a year, timed around its growing season. Texas A&M AgriLife's maintenance calendar says to make the first application once the lawn is actively growing and has been mowed at least twice, then apply nitrogen 1 to 4 more times through the growing season, with the last application 4 to 6 weeks before your area's first historic frost. AgriLife caps St. Augustine at 4 lbs of nitrogen per 1,000 square feet a year.
Here is the timing Texas A&M AgriLife's calendar lays out, in plain terms.
Spring: wait for active growth, not a date
AgriLife's calendar says to "make the first fertilizer application when the lawn is actively growing and has been mowed at least two times," not on a fixed calendar date. AgriLife also says not to fertilize a stressed lawn.
Through the growing season: light, repeated feedings
AgriLife recommends 0.5 to 1 lb of nitrogen per 1,000 square feet, applied 1 to 4 times during the growing season with a mix of quick- and slow-release fertilizer, and says not to exceed 4 lbs of nitrogen per 1,000 square feet in a year. Apply other nutrients based on a soil test, not a guess.
Fall: stop well before frost
Make your last nitrogen application 4 to 6 weeks before your area's first historic frost, per AgriLife's calendar. After that, the next scheduled feeding is the following spring, once the lawn is actively growing again.
Keep the rest of the calendar in mind
Fertilizer timing works best alongside the right mowing height and watering schedule; see our St. Augustine care guide for the full routine and our lawn care schedule for how it fits with the rest of the year. If you are specifically asking about fall feeding timing, our fall fertilizer guide covers that cutoff in more detail.
New sod needs a different approach than an established lawn. Design your lawn or talk to our team about what to do in the first few months after your sod arrives.
