vinegar has a pH of about 3 on the pH scale. and you want your plant around 7. so if you were to dilute a teaspoon or 2 into a gallor on water, that would probly work. but to much would deff. burn your plants up, so be careful
vingar is fine to take ur ph down, i used it last year with no problems. simply test your water, add a cap of viegar, test again etc etc.... untill you have the ph you wish to acquire.