Although it is perhaps one of the most overlooked aspects, pH is very important in hydroponic and organic as well as regular soil gardening. pH is measured on a scale of 1-14 with 7 being neutral. Acids are lower than 7 and alkalis (bases) are above 7. The ideal pH for a plant in a hydroponic system is 5.8, if the pH is wrong it can stop the plants roots from uptaking the minerals. This will cause the plant to run outa food and may suffer permanent damage towards the roots.