Apply corn gluten meal as organic fertilizer and mild pre-emergent

What to Do

Spread corn gluten meal (9-0-0) at 20 lbs per 1,000 sq ft in mid-spring. It provides slow-release nitrogen and has a mild pre-emergent effect on crabgrass and other annual weeds.

Why It Works

Corn gluten meal inhibits root formation in germinating seeds while feeding established grass. Iowa State University research first identified its herbicidal properties. The nitrogen releases gradually over 3-4 months as it decomposes.

Tips

• Pre-emergent effectiveness is modest (50-60%) compared to synthetic options — best suited for lawns with light weed pressure.
• At $30-80 per 1,000 sq ft for weed-control rates, it is significantly more expensive than synthetic alternatives.
• Do not use if you plan to overseed — it inhibits all seed germination, including grass seed.