I'm taking over maintenance on a Floratam St.

Cut at 3.5–4 inches. For Floratam in North Florida, this is the non-negotiable standard (UF/IFAS ENH10/LH010).

The 1/3 Rule: Never remove more than 1/3 of the total blade height per mowing.

• Target height: 4 in.
• Max height before cut: ~5.3 in.
• Max clipping length: ~1.3 in.

Why this matters for Floratam:

• Coarse texture: Wide blades scalp easily if cut low. Scalping = dead crowns = weed invasion (dollarweed, sedge).
• Shade tolerance: Floratam needs leaf surface for photosynthesis. Lower cuts kill density in filtered light.
• Root depth: Mowing height ≈ root depth. 4 in. top = 4+ in. roots (drought survival).
• Thatch: Floratam produces heavy thatch. High cuts keep stolons shaded/cool, slowing thatch buildup.

Jacksonville specifics:

• March–Oct: Mow weekly (5–7 days). Growth explodes in June–Aug.
• Nov–Feb: Every 10–14 days. Don't mow dormant grass.
• Sharp blades only. Dull blades shred Floratam’s tough blades → brown tips → disease entry (Gray Leaf Spot, Take-All Root Rot).
• Mulch clippings. Returns ~1 lb N/1000 sq ft/yr. Does not cause thatch if 1/3 rule followed.

If it’s overgrown (>6 in.): Raise deck to max, cut, wait 3 days, drop one notch, repeat until 4 in. Never scalp down in one pass.

Pro tip: Check height on concrete, not grass. Deck wheels sink in turf.

For Floratam St. Augustine grass in Jacksonville, FL, maintain a mowing height of 3.5 to 4 inches. This is the recommended range per University of Florida IFAS Extension guidelines for warm-season turfgrasses in subtropical climates like Northeast Florida.

Key mowing practices:

• Never remove more than one-third of the grass blade in a single mowing. For example, if your lawn is 6 inches tall, do not cut below 4 inches (removing 2 inches, which is ⅓ of 6"). Cutting more stresses the grass, reduces root development, increases weed invasion, and makes it more susceptible to disease and drought.
• Mow frequently enough to stay within the 1/3 rule — typically every 5–7 days during peak growing season (spring through fall).
• Keep mower blades sharp to avoid tearing, which invites pathogens.
• Leave clippings on the lawn (grasscycling) if they’re short and not clumping — they return nutrients and moisture.

Floratam is less tolerant of low mowing than other St. Augustine varieties; cutting below 3.5 inches can thin the stand and encourage chinch bugs and fungal issues.

If the lawn is overgrown, gradually reduce height over multiple mowings (3–4 days apart) to avoid shock.

Bottom line: Set mower to 3.5–4", mow often, and never cut more than ⅓ of the blade height per pass. For Jacksonville’s climate, this promotes dense, healthy turf that resists pests and weeds. (Source: UF/IFAS ENH11, "St. Augustinegrass for Florida Lawns")