Organic St. Augustine (Floratam) Management in Florida: Soil Health Over Chemicals

A Florida homeowner with Floratam St. Augustine wants to control crabgrass organically after pre-emergents failed in spots.

Why Chemicals Fail

• Pre-emergents kill soil microbes that suppress weeds naturally.
• St. Augustine is naturally dense; weeds invade only when grass is stressed (wrong fertilizer, water, mow, pH).
• Sandy Florida soils leach nutrients; synthetic fertilizers wash through, requiring constant reapplication.

Organic Foundation Program

1. Mow correctly: 2 inches in sun, 2.5–3 inches in shade. Mow frequently, early morning. Sharp blade.
2. Replace dead patches NOW (summer) with plugs/sod when temps >65°F.
3. SOIL TEST: USDA map for local extension: csrees.usda.gov.
4. Compost tea: Reintroduces microbes killed by chemicals. Recipe: 1 shovel Alaska humus in 5-gal rainwater, stir daily 1 week, add 2–3 tbsp molasses, optional additives (fruit, cornmeal, kelp, etc.), aerate with aquarium pump. Use when foamy.

Why Compost Tea?

Restores the soil food web: bacteria, fungi, protozoa, nematodes that cycle nutrients, suppress pathogens, and build structure. Golf courses use it for fungus prevention.

Long-Term

After soil test corrections, minimal inputs needed. St. Augustine thrives on benign neglect in healthy soil.