okay my friend in california is growing medical marijuana and is wondering how to raise and lower ph in soil, his plants are already in the soil and hes wondering just in case he comes across having to lower or raise his ph levels, so what simple items will work like you can find at wal-mart or home depot ect. and how to use them? i dont want stuff hard to find just simple stuff thanks! hes not doing this anything illegal.
to raise the ph, use lime. To lower the ph (make more acidic), use soil sulfur. You need to test the soil before adding, and only use the amount per square foot that the bag indicates.
