how to kill crabgrass

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how to kill crabgrass

To kill crabgrass effectively, here are the key methods:

  1. Manual Removal: For small patches, pull crabgrass by hand or use a weeding tool early in the season before it seeds to completely remove roots.
  1. Pre-Emergent Herbicides: Apply pre-emergent herbicides like Weed & Green or Scotts Turf Builder Halts in early spring before crabgrass seeds germinate, when soil temperature reaches about 55°F. These prevent crabgrass from growing.
  1. Post-Emergent Herbicides: For established crabgrass, use post-emergent herbicides containing active ingredients like quinclorac (e.g., Bio Advanced Lawn Weed & Crabgrass Killer), mesotrione (e.g., Tenacity), or herbicidal soap (like Weed Warrior). Repeat applications spaced 2-3 weeks apart may be needed. Exercise caution as these can harm desirable grass if not applied carefully.
  1. Boiling Water: Pour boiling water on the crabgrass and surrounding area to kill the roots in small patches.
  1. Lawn Care Practices: Maintain lawn health by mowing high (removing no more than 1/3 of the grass blade), overseeding or planting new grass to crowd out crabgrass, watering deeply but less frequently to strengthen grass roots, and reducing soil compaction.
  1. After Treatment: Remove dead crabgrass, dethatch, aerate, and overseed bare spots to promote healthy grass growth and prevent re-infestation.

Summary Table of Crabgrass Control Methods:

Method| Description| Best Use
---|---|---
Manual Removal| Pull or dig out early before seeding| Small patches
Pre-Emergent Herbicides| Applied before seed germination to prevent growth| Early spring, preventive
Post-Emergent Herbicides| Chemical kill of existing crabgrass| Established crabgrass
Boiling Water| Pour hot water to kill small patches and roots| Spot treatment
Lawn Care Practices| Mowing, watering, overseeding, soil care| Overall lawn health and prevention
Lawn Renovation| Dethatching, aeration, overseeding after kill-off| After herbicide treatment

By combining these approaches, crabgrass can be effectively controlled and prevented from spreading.