Peroxide will also help raise ph, when used correctly... as well as many other benefits but if you use the common household type (hydrogen peroxide 3%) then be careful- I'd do a drop-a-gal at a time (anymore than .5 mL will hurt plants tremendously I presume.) In a pickle, you can use one of these alternatives to save your a*s but you really need to buy some real pH up as soon as you can. The peroxide will only raise your pH a tiny bit so if it's way off then go with something else. Chemical nutrients lower pH most of the time too. I just realized how ancient this thread is, hahaha; oh well, regardless- anytime one asks for help concerning pH, you should specify your growing method (soil/hydro) & other details like the type of nutrients being used, etc.