Using Corn Gluten Meal for Crabgrass Prevention on Long Island

What Is Corn Gluten Meal (CGM)?

CGM is an organic pre-emergent herbicide that inhibits seed germination while breaking down into slow-release nitrogen. It must be applied at the precise time—when forsythia blooms—to stop crabgrass and other annual weeds.

Where to Buy on Long Island

• Hicks Nursery (Jericho Turnpike) – top organic supplier, carries CGM and ladybugs.
• Marders Nursery (Bridgehampton) – Renaissance 10-0-0 Organic Pre-Emergent.
• Papa Farm & Greenhouse (Central Islip) – may carry Blue Seal Safe 'N' Simple.
• Goetz & Sons Feeds (Ronkonkoma) – Blue Seal dealer.
• Big-box stores: "Preen Vegetable Garden Weed Control" (CGM-based) at Ace, Home Depot, Lowe's, etc.
• Local nurseries: The Garden Works, London Landscape, Cipriano Nursery, Garden World, Atlantic Nursery, Dee's Nursery, Giordano's, Garden Gate, Abby's Parkside, Westminster Nursery.

Critical Timing and Practices

• Apply CGM during forsythia bloom week—order early to avoid stockouts.
• Mow high (2–3 inches for bluegrass) and often; proper mowing alone can reduce weeds by 90%.
• Leave clippings to recycle nitrogen.
• Water deeply, not on a fixed schedule.
• Overseed bare spots only after 4–6 weeks (or 3 months for safety) because CGM stops all seed germination.
• Consider a nitrogen-fixing cover crop (clover, alfalfa) in bare areas instead of grass seed during the waiting period.

Avoid Synthetic Products

Do not use Scotts Crabgrass Killer or similar—it kills soil microbes and creates dependency on synthetic nitrogen.