pH is the measure of the acid content of a certain solution. The pH scale can measure pH levels of between 1 and 14, with 1 being extremely acidic, 7 as neutral, and 14 as extremely basic. pH has an effect on the ability of a plant's roots to take in nutrients. The best pH level for nutrient absorption is between 5.8 and 6.5. How to measure pH pH can be measured by either chemical means or electronic means. You can buy chemical test kits for around $8 to $18, and they are quite reliable. The ...