Measuring pH Levels in Hydroponics


If you want to achieve optimal growth in your hydroponic garden, and see healthy, thriving results, it’s important to be regularly measuring pH levels of your nutrient solution. This can be done with pH testers and adjustments to pH levels can be made accordingly.

What is pH?

Though the exact meaning is unknown, it’s thought that pH stands for “power of Hydrogen” or “potential for Hydrogen”. pH is the measurement of the alkalinity or acidity levels in a water solution. It’s measured on a scale from 1 to 14 where the lower half of the scale is acidic and the upper half is alkaline. A perfectly pure solution is a 7 on the pH scale.

What Does pH Mean in Hydroponics?

In hydroponics, the ideal or standard pH level for plants is between 5.5 and 6.5.

This pH level is ideal for the absorption of essential micro and macro nutrients by the plants’ roots. A higher presence of macro nutrients like Nitrogen, Phosphorus, and Potassium is found within this range meaning the plants’ are growing in an optimal state.

If your pH level is incorrect or too extreme one way or another then your plants won’t be absorbing proper nutrients and will become weak and could eventually die.

Measuring pH Levels in Hydroponics

When first starting out with your hydroponic garden, you’ll want to check the pH level of your nutrient solution daily. You’ll likely need to continue this until you develop an understanding of your system and plants’ needs.

Adjusting pH Levels

When measuring pH levels it’s likely you will need to adjust one way or another. There are products available at your hydroponics retail store or online which are specifically designed to lower or raise your pH level. You can also lower your pH level yourself by using citric acid.

We recommend using General Hydroponics pH Up or pH Down products which are available at any indoor gardening supplier and are also available online.

Use a pH Tester

As a beginner it’s easier to stick to the old fashioned method of testing pH levels by using simple paper strips. These strips are coated in special dye that when dipped into the solution will indicate a color. You then compare that color to a pH color chart which tells you which pH level your solution is at. This method is not always the most accurate however.


If you want to advance your hydroponics skills past the beginner level, you can try using a liquid pH testing kit. This is where you drop dye into the solution which changes color to indicate the pH level. These liquid pH testing kits are also available at your local hydroponic retail shop or online.

The most accurate way to test your pH levels is by using a digital pH tester. These digital meters are available in a number of price ranges with the simplest one being a “pen” style meter. You just insert the pH meter’s tip into the solution until a pH level reading is registered on the digital screen. These digital meters are available at any hydroponic retailer and are also widely available online.

Here are some digital pH meters different price ranges:

  • Hanna Instruments Hanna Checker pH Tester ($45 approx.)
  • HM Digital pH 80 Meter ($60 approx.)
  • Bluelab pH Pen ($110 approx.)

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