Understanding pH Hydroponic Growing

Imagine your seedlings growing as fast as Jack's beanstalk. Every hydroponics gardener dreams of such an experience. Growth that fast only happens in fairy tales - but we can tell you, if you get the growing conditions right, you'll see plant growth that wows you, not to mention your friends and family. One of the most important hydroponic growing conditions to monitor is pH balance.

A hydroponic growing solution's pH levels dictate how well plants will be able to absorb nutrients carried in the solution. Almost all plants absorb hydroponic nutrients best when the pH level is between 5.5 and 6.2. You might remember from high school chemistry class that a pH of 7 is neutral. Anything below 7 is acidic; anything above 7 is alkaline. So, for hydroponic growing, the solution needs to be slightly acidic. If the solution drops lower than the optimum range or goes above it, the nutrients in the solution can't be absorbed as easily, and the plant will not grow the way you think it should.

To monitor the pH levels of your hydroponics growing solution, you can purchase a pH meter, one of the most important hydroponic supplies. For all you science geeks out there - pH measures the electro-chemical potential of hydrogen (which is what "pH" stands for) in any given solution. A simple pH kit uses chemical reactions between the nutrient solution and the kit test solution to indicate acidity or alkalinity.

Adjusting pH for Optimum Hydroponic Growing Conditions

If you use a pH meter to monitor your hydroponic growing solution and find that the pH level is too low, you can add either potassium hydroxide or nitric acid to bump it up. Conversely, if you find that the level is too high, you can add phosphoric acid or sulfuric acid to bring it down. Often, after you apply all the nutrients and enhancers you need to carry out your hydroponic growing plan, you'll find that the pH of the solution is too low, and you'll have to add a pH boosting product to make all that work worthwhile. Different hydroponics growing media can affect pH differently, as well.

Calibration of Your pH Meter

It's critical to keep your hydroponic pH meter calibrated, and it will naturally lose calibration without doing a thing. Time, frequent use and old batteries all contribute to a pH meter losing calibration. It's not a bad idea to calibrate once a week when you are using the meter often to make sure your readings are correct, or you might adjust the pH incorrectly and sabotage your results.

Calibration involves using a calibration test solution with a reading of 7 and one with a known reading of 4. First, you rinse the probe in water. Then you insert it into the calibration solution with a pH of 7 and turn a screw or press a button to show "7" on the meter. Then, you do the same with the calibration solution that has a pH of 4. Every pH meter is a little different in the way it is calibrated.

As you can see, pH is a very important part of the hydroponic system. Get it right, and your plants will grow as high as the ceiling with leaves as big as your head and stems weighed down by fruit and vegetables ... just kidding. But that's the dream of every hydroponic gardener, and you'll get much closer to the dream if you pay attention to pH.