I noticed last year when I drained it out in the yard, that nothing has grown on that spot for over a year. This time I caught it in buckets when I drained it, put it in a sprayer and applied it to the driveway. Weeds turned yellow and have decreased. Don't know if it works as well as real weed killer, but it's only about $2.40 a bottle. Cut it with a couple gallons of water, and it's a better deal than paying $15 for weed killer, I'm just sayin'........