Monthly Archives: July 2015

Hydroponics and pH

Many people believe acidity shouldn’t be a factor in hydroponics because it’s something that only happens in soil. In reality, it’s just important if not more to monitor and adjust acidity in hydroponics as in your backyard garden. If the water doesn’t have the proper levels of pH, then the crop will not grow properly.

young tomato plantThe Basics Of pH

pH measure the overall acidity of a substance on a scale of 1-14. If the water has a high concentration of hydrogen ions, then it is acidic and will register between 1-6.9. If it has more hydroxyl ions, then it’s alkaline and will measure between 7-14. For hydroponics, the levels should be somewhere between 5.5 and 6.5 for most crops. pH levels below 5 and above 7.5 will likely kill the plant.

The acidity of the water makes a difference in how the plant will absorb necessary nutrients. Everyone wants succulent fruit and colorful vegetables, but that isn’t going to happen if the plant can’t absorb the iron, nitrogen, etc. In hydroponics, the nutrients are in the solution and can precipitate out and stick to the walls of the chamber, if the pH is off. If it’s not suspended in the solution, then the plant can’t absorb it.

How To Measure pH

Measuring pH can be as simple or complicated as you want. The simplest and least expensive is to use testing strips. The strips have a dye that reacts to the pH of the water and will change color. Compare the color to those listed on a chart, and you can determine the rough pH level. The downside is it lacks accuracy given that there are many variables in the solution that can cause the strips to be off color and you’re “eye-balling” it rather than getting an actual reading.

A liquid test involves putting solution into a vial and adding a few drops of the dye. The entire solution will change color and then compare it to a color chart. The color is more defined, so it’s a more accurate than the paper.

A pH reader can give an actual number and involves placing an electrode into the water and taking a reading. This is the most expensive option, but the most accurate. The only downside is the meter must be calibrated regularly or else it may provide an inaccurate reading.

cucumber plant in greenhouse.Changing pH

If the pH balance is off, then it must be adjusted. There are products designed for hydroponics that will raise or lower the pH, but the general rule is that if it’s too acidic, then something alkaline must be added and vice versa. Be very careful adding acids and other chemicals to the hydroponics as it can not only harm your plants if not done carefully, but also cause serious injury to the hydroponic gardener.

pH balance is often overlooked by many with devastating consequences because they don’t believe it applies to hydroponics. It’s a vital and simple measurement that could mean the difference between a bumper crop and complete ruin.