Organic Nutsedge (Nutgrass) Control in St. Augustine

Why Chemicals Fail

Atrazine kills visible nutsedge but doesn't touch the tubers (nutlets) deep in soil. When chemical degrades, tubers resprout. Plus, Atrazine harms soil biology and can damage St. Augustine.

Organic Strategy: Change the Soil, Starve the Weed

• Sugar (4 lbs/1,000 sq ft, spring/fall): Feeds microbes that improve soil structure. Nutsedge thrives in wet, compacted, anaerobic soil—healthy biology fixes this.
• Corn gluten meal (20 lbs/1,000 sq ft, early spring): Pre-emergent suppresses new seedlings; adds nitrogen; fungicidal.
• Deep, infrequent watering: Nutsedge loves constant moisture. Water 6+ inches weekly, let surface dry.
• Improve drainage: Core aerate, topdress with compost.

Persistence Pays

Nutsedge tubers can persist years. But in biologically active, well-drained soil, they weaken and eventually die out. Combine with hand-pulling (get tubers) when soil is moist.

Source for Corn Gluten

Nurseries with organic sections or feed stores. Brands vary—look for "corn gluten meal" or "corn gluten herbicide."