So I’ve got a lot of plants/weeds around my place, and I want to kill most of them… but herbicides are expensive when you start looking at buying gallons of it, and I don’t want my house sitting in the middle of a chemical soup bath either. Fortunately, the answer is simple;
The vinegar kills weeds, the salt stops them from regrowing, and the dish soap holds everything in place until the job’s done. If you want to grow another plant in the spot immediately, hold off on the salt as it can stick around for a while and hinder future growth. Extrapolated WMD style large scale plant death = 10 gallons vinegar to 10 quarts salt and 10 quarts soap.
Of course, higher concentrations of acetic acid in your vinegar are better. Here’s a study that shows the effectiveness of such treatments compared to RoundUp. The one thing the study doesn’t reveal is the cost difference. 1 gallon of “super concentrate” RoundUp costs $110 at my local hardware store and supposedly covers 25,500 square feet, which is barely over 1/2 acre. I was actually able to find a restaurant supply store selling 4 packs of 1 gallon vinegar jugs for only $6.00! That’s 4 gallons of vinegar for $6.00! But even at retail prices, I could find 2 packs of 1 gallon jugs for $20.00. Salt and soap are also very cheap.