St. Augustine Fertilizer Guide
Nitrogen needs vary by region: North Florida 2-4 lbs N/1,000 sq ft/year, Central Florida 2-5 lbs, South Florida 4-6 lbs. Use a 2-1-1 N-P-K ratio (e.g., 16-8-8) — St. Augustine prefers more phosphorus relative to potassium compared to bermuda's 4-1-2 ratio. Slow-release nitrogen sources (at least 50% slow-release) reduce surge growth and disease pressure. Apply iron sulfate or chelated iron for deep green color without pushing excessive leaf growth. Do NOT fertilize in winter or when lawn is dormant. First spring application after full green-up, last application 6 weeks before expected first frost.
Frequently Asked Questions
How much nitrogen does St. Augustine need?
It depends on your region. North Florida: 2-4 lbs N per 1,000 sq ft per year. Central Florida: 2-5 lbs. South Florida: 4-6 lbs. More sun and longer growing seasons need more nitrogen.
What NPK ratio is best for St. Augustine?
A 2-1-1 ratio (N:P:K) is preferred — different from bermuda's 4-1-2. St. Augustine benefits from higher potassium relative to nitrogen for stress tolerance.
Should I reduce nitrogen in summer?
Yes. Reduce or eliminate nitrogen from June through August to avoid promoting gray leaf spot disease. Use iron supplements for color without the disease risk of excess nitrogen.
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