1. Reference articles
  2. pH (Potential Hydrogen)

What is pH? Why do I need to measure it? What do I use to measure it?

Potential Hydrogen, commonly known as pH, is a number that indicates the acidity (below 7.0pH) or alkalinity (above 7.0pH) of a solution. 

It is important to maintain a hydroponic nutrient solution at a pH where elements in the nutrient solution are most available to the plant.

  • Each element has a pH range in which its availability is maximised.
  • In hydroponics, the range in which most elements are available is typically between 5.5pH and 6.5pH.
  • Strong acid (low pH) or strong alkali (high pH) conditions can upset the balance of a nutrient solution.
    • This can cause a loss of uptake for specific nutrients by the plants roots.
    • This is know as "lockout", whereby certain elements become unavailable to the plant due to pH.

Measure the pH of a nutrient solution daily to ensure maximum availability of nutrients to the plant, and to avoid "lockout". 

Bluelab offer a range of meters to measure pH, including our Bluelab pH Pen - our simplest handheld pH meter available: 

Our most popular meter, the Bluelab Combo Meter, offers pH testing, conductivity testing, and also temperature measurement:

Our latest meter on offer is our Bluelab Multimedia pH Meter - this meter is able to test the pH of your growing medium by direct measurement (the probe is placed directly into the growing medium) - this allows you to take pH readings directly from your plant root zone:

To see our full Bluelab product range, please click here.