Green Thumb Academy 

PH Basics

  • What is pH?

  • Why is pH important to me?

  • How do I measure pH?

  • Do I need expensive gear?

What is pH?

Wikipedia defines pH as:

The USGS defines pH as:

  • pH is a measure of how acidic/basic water is. The range goes from 0 to 14, with 7 being neutral. pHs of less than 7 indicate acidity, whereas a pH of greater than 7 indicates a base.

The importance of proper pH
  • Proper pH boosts plant size, flower production and cannabinoid levels.

  • Proper pH of medium and water maintains plants ability to absorb nutrients and grow big buds.

  • Proper pH prevents nutrient lockouts.

How do I measure pH?

There are 3 methods of measuring pH.

  • pH pen - Turn it on, place the end of the pen in the liquid being measured and wait for the pH reading to stabilize.

  • pH test strips - Dip the test strip in the liquid being measured. Once it changes color, compare to the chart provided with the test strips.

  • pH test kit with glass vial - Fill the vial with the recommended amount of liquid. Add the drops, shake, and compare to the chart provided with the kit.

What equipment do I need?
  • pH Pen

  • pH solution (4.0 and 7.0)

  • Storage solution

  • 2 shot glasses or other small containers.

How and when to calibrate my pH meter.
  • When - Calibrate once the pen loses its 'calibrated' check mark, or every other month.

  • How - Follow the instructions that are included with your pen. Click here for a video showing how to clean and calibrate a Blue Lab pH pen.

Tips and Tricks
  • Keep storage solution in the cap of your pen and always store it properly. If the sensor in the tip of the pen drys out, it dies.

  • Use a toothbrush and mild dish detergent to clean the tip of the pen. Rinse thoroughly.