That claim is misleading. A product may make weeds wilt or brown very quickly, but “burns weeds in 1 day” does not mean they will never grow back.
Contact herbicides can produce visible injury within hours, but they may leave the roots or growing points alive, allowing regrowth.
M
Minnesota Crop News
+1
Systemic herbicides move through the plant and can provide more thorough control of established perennial weeds, but symptoms may take several days to appear.
M
Minnesota Crop News
New weeds can also emerge later from seeds already in the soil, so killing today’s weeds doesn’t necessarily prevent tomorrow’s weeds. Pre-emergence/residual strategies can help with that.
U
University of Minnesota Extension
Repeated use of the same herbicide can also select for herbicide-resistant weeds.
U
University of Minnesota Extension
So I’d treat “one day and never again” as a marketing claim, not a guarantee. The right treatment depends heavily on the weed species and whether you need to protect nearby grass, crops, trees, or other plants.
M
U
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