Household vinegar is an effective weed killer.
Contested
Vinegar only burns the tops of small, young weeds — it doesn't reach the roots, so established and perennial weeds grow right back, and it kills whatever it touches, including your crops. The stronger "horticultural" vinegar is caustic, not gentle. Use it for seedlings in pavement cracks, not as a lawn-and-bed weed killer.
What is actually known
Household vinegar (about 5% acetic acid) is a contact desiccant: sprayed on a sunny day it burns the top growth of young, small annual weeds. It does not move into the roots, so anything established or perennial regrows from the crown within a week or two, and it is not selective — it burns whatever it lands on, crop included. The stronger "horticultural" vinegar (20%+) is not a gentle alternative: it is a corrosive that can burn skin and eyes and needs real protective gear. For seedlings in cracks it is a fine spot treatment; for a real weed problem it is not the tool it is sold as.
Evidence: not yet confirmed against its 1 source.
what this rests on - one pointer
acetic acid is a non-selective contact desiccant that does not translocate to roots; horticultural vinegar is corrosive; extension weed-management guidance
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