@Carol. I put straight apple cider vinegar in a spray bottle. During full sun (sunlight must be falling on the weed) spray the leaves of the weed. I use it mostly on clusters of small, young weeds. Here in PHX (hot and sunny) the weed is dead in a day. Something to do with smothering. I also poured straight cider vinegar onto Bermuda grass and it died in that spot. However, the Bermuda grass surrounding the treated area did in time invade that space. But, yes. I've had good luck spraying it on leaves of weeds in full sun. Otherwise I use the trusted knife and yank out the root.