First of all, what exactly is pH? The pH scale measures the level of acidity and alkalinity in a given substance. This measurement is done on a scale of 0 (zero) to 14, with anything above seven being considered as alkaline and anything less than seven being considered as acidic. Pure water has a neutral pH of seven, and its pH shifts with the addition of salts, which then form a solution. When growing plants, the pH of your water, your nutrient solution, and your soil all impact the availability of each nutrient your plant needs to grow and thrive. When checking your pH during the growing process, you want to make sure it is kept within an acceptable range for the given growth media being used. For instance, in a hydroponic media, this acceptable range would be between pH 5.8 to pH 6.2. However, in a soil media, your model range will be between pH 6.2 and pH 6.5. Keeping within these ranges does not make all of the nutrients the most available to the plant that is possible for them to be, but rather, it makes them available to the plant in the ideal ratios that the plant needs for optimal growth. Also, it is important to note that the plant seems to flourish when fed at a range of pHs instead of at a specific number, so if you are placing your nutrients into a reservoir and they are drifting up over time, then you know that if you adjust the pH to 5.8 they will move up and then through the acceptable range, as opposed to adjusting to 6.2 and immediately have it move out of range. pH is measured when growing by the use of a pH probe. A pH probe is nothing more than a pH electrode attached to a voltmeter, which measures the electrical charge in a solution and then converts that data to a readable and consistent scale. These devices can be tedious to maintain, so always make sure that your pH probe stays submerged in pH neutral solution when not in use, that your voltmeter does not submerge completely, and that you clean and calibrate your meter as frequently as is recommended by the manufacturer. These steps will prolong the life of your meter substantially, while insuring that your measurements are as accurate as possible throughout that life. Once you have an idea of what your base pH is (thanks to your meter!) it is time to adjust it to within the desired range. Most commercial pH adjusters are either potassium hydroxide, for pH up, or phosphoric acid, for pH down. This is important information to be aware of, because these two substances will contribute to the PPM, or Parts Per Million, of your solution. It is also important to be aware of the fact that if you add pH down to your solution and overshoot your desired pH, it is not detrimental to the plants to adjust that solution back up using the pH up. Combining these two substances will do nothing but create water and potassium phosphate, which accounts for your PPM jump. With a basic understanding of what pH is, how it is accurately measured, and how it is safely corrected, you can make sure your plants have everything they need at any given time to be as successful as possible. This article was previously published by Tucker Eldridge and the NoCoMAC.
