Getting started: The Bluelab Soil pH pen

Product overview and how to get started

The Bluelab Soil pH Pen


The Bluelab Soil pH Pen is an accurate way to measure soil pH and temperature directly in the root zone of your plants soil and media. If needed, the soil pH pen can be used in nutrient solutions.

Simply make a hole in your soil or media with the attached soil dibber and insert the probe to get consistent pH and temperature measurements.


Selectable units for °C and °F

Fully waterproof

Backlit LCD display

Hold reading function

Integrated storage cap / dibber

Auto-off function

Register your product with Bluelab 

Product manuals:

PENSOILPH User Manual - English

PENSOILPH User Manual - Dutch

PENSOILPH User Manual - German Deutsch

 To operate

Important: You must calibrate your pH pen before first use. 

  1. Use the storage cap/dibber to make a hole in your soil or media. Go as deep as your plant roots.
  2. Gently remove the storage cap by unscrewing the cap first and gently pulling to remove the probe. The cap contains KCl solution, so be careful not to spill the liquid.  Salt crusting around the probe is normal. 
  3. Turn the pen on and insert the probe into the hole. Ensure the probe tip is contacting the soil at the end of the hole. The display will stabilise giving you your pH and temperature measurement.
  4. Rinse after use to remove nutrient or soil buildup and replace the storage cap/dibber.

Read more on how to operate the Soil pH Pen

How to measure the pH of soils and media


Calibrate after every clean and at least monthly.

  1. Turn the pH pen on.
  2. Calibrate to pH 7 by placing probe tip in fresh pH 7 solution. Wait for reading to stabilise to between pH 6.6 - pH 7.5.
    Long press the Cal button until CAL is displayed. Release the button. A calibration sequence will start sequentially flashing “0” across the display. After “0000” stops flashing, the sequence is complete. Rinse the probe tip in fresh tap water.
  3. Repeat with pH 4 solution.
  4. A checkmark will confirm successful calibration.

Read the guide on how to calibrate your pH probe (+ video)

Monthly care 

Clean and calibrate your Soil pH Pen at least once a month to keep the probes accurate. If the probe accidently dries out, hydrate the pen for 24 hours using Bluelab KCl solution.

Follow our monthly care guide for instructions on how to look after your Soil pH Pen

Useful links

FAQ and troubleshooting for Bluelab pH probes and pens 

How to replace the batteries in the soil pH pen


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