Eradicating Torpedo Grass in Centipede Lawn: Solarization Strategy

Torpedo grass (Panicum repens) is a Category 1 invasive in Louisiana — rhizomatous, fire-adapted, herbicide-resistant. Selective removal from centipedegrass is nearly impossible chemically. Soil solarization is the most effective organic eradication.

Why Chemicals Fail

• No selective herbicide kills torpedo grass but spares centipede
• Glyphosate kills both — requires total renovation
• Rhizomes 12-18" deep escape treatment
• Disturbance (tilling, pulling) stimulates growth

Solarization Protocol (Summer Only)

1. Timing: Hottest 6-8 weeks (July-Sept in LA)
2. Prep: Mow scalp low; till entire area 6-8" deep
3. Amend: Spread 2-3" aged manure + 1" compost (fuels heat)
4. Water: Saturate to mud consistency 12-18" deep
5. Cover: Clear 6-mil UV-resistant plastic; seal edges with soil
6. Duration: 6-8 weeks minimum; 10-12 weeks better
7. Monitor: Soil temp should reach 120-140°F at 6" depth

Post-Solarization

• Remove plastic; do NOT retill (brings up deep weed seeds)
• Plant centipede sod immediately (best) or seed (late spring)
• Apply corn gluten meal (20 lbs/1,000 sq ft) for pre-emergent
• Monitor edges — torpedo grass reinvades from borders

Containment If Full Solarization Impractical

• Deep edging (24" HDPE barrier) around centipede area
• Regular glyphosate spot-treatment on torpedo grass only
• Accept some coexistence; manage, don't eradicate

Solarization works by superheating moist soil — kills seeds, rhizomes, pathogens. Manure/compost generates additional heat via microbial activity. One thorough treatment can reset the seed bank.