Post-Emergent Herbicide
A herbicide applied to weeds that are already visible and growing above ground. Post-emergent products are what most homeowners use when they see weeds in their lawn. They are most effective when weeds are small and actively growing.
Post-emergent herbicides are the opposite of pre-emergents — instead of preventing germination, they kill weeds that have already sprouted. They work by being absorbed through the leaves or roots of the weed.
Best timing: Apply when weeds are young and actively growing. Small weeds are much easier to kill than mature weeds with large root systems. Avoid applying in heat (above 85°F) or drought stress.
Contact vs systemic: Contact herbicides (like diquat) kill only the parts they touch — fast but may not kill the root. Systemic herbicides (like glyphosate, 2,4-D) move through the plant to the roots and kill the whole plant.
More on Weed Killer
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