When growing cannabis indoors one of the things that will need to be done often is to test the pH level of the soil, this is because the plants will not grow well in soil that has either to high of a pH level or too low of one. The perfect level for the soil that the marijuana plants are growing in is a pH 7 and there are ways to make certain the level stays at this optimum level, like water that is to alkaline can be neutralized by using certain things. The use of sulfuric acid, vinegar or even vitamin C can neutralize water with too much alkaline and these should be used with caution. Adding to much of any of these things can result in burned leaves on the ganja plant.