The pH of the water is of major importance; it greatly affects plant growth. The symbol pH represents a measure of the concentration of hydrogen ions per liter of water and thus a measure of the acid-alkaline balance of the water. This balance is often unfavorable in the natural water supply of the area.
But the pH of water can readily be changed for use in hydroponics. First, however, you need to know what the present pH is. The higher the concentration of hydrogen ions, the more acid; the lower the concentration, the less acid. Below 7.0 may be considered acid; above 7.0, alkaline. Your water supply source can tell you what the pH of your water is, although it does vary from time to time.
There are several simple kits on the market for testing the pH of your water. One involves the use of Nitrazene tape. There is also a kit utilizing a chemical that you drop into a sample of your water. In each case, either the tape or the water changes color. You then compare the color with those on a chart indicating the approximate pH. You can use both systems, in fact; one as a check on the other. You may also purchase a meter, if you wish.
By whatever method, the pH of your water, the the nutrient solution you are using in hydroponic growing, should be checked every four days.