How to operate the Bluelab Soil pH Pen

Before you use the Bluelab Soil pH Pen, you need to calibrate the pen to two pH points. 

If you notice that your probe is dry, you will need to hydrate your pH pen for 24 hours in KCl solution. 

1. Prepare soil

Remove the top layer of soil/media from the surface of the sample area.


Note: The Soil pH Pen will automatically turn off after 4 minutes to conserve battery power. 

2. Measure the pH of your soil or substrate

Measure the pH of soil by inserting dibber


1. With the storage cap/dibber on the pen, press the Soil pH Pen into the sample area until it reaches the word "Soil" at the top of the dibber. Remove gently from the soil or substrate, leaving a small hole. 

Important: Unscrew the cap/dibber first, then gently pull the probe from the dibber. There will be KCl solution in the probe holder, so be careful.  

2. Remove the storage cap/dibber from the pen gently. Turn the Soil pH Pen on, by pressing the Power button. (The last measurement is recalled for 3 seconds. To turn the pen off, press and hold the Power button until OFF is displayed.) Place pH probe into the hole in the soil or substrate. Do not exert sideways pressure. Wait for the reading to reach a consistent value. 

Note: Never make a hole in the soil or substrate with the pH probe. Always use the storage cap/dibber

3. To hold reading

Use the hold reading function on the soil pH probe

To hold the measurement on the LCD screen, short press the power button. To exit the hold function, short press the power button again. 

4. To change temperature units

To toggle between °C and °F, press and hold the Units button, then short press it to switch modes when the display starts to flash. To exit, don't press anything for 3 seconds.

5. Rinse and place on the storage cap and dibber 

To ensure accurate pH measurements, always rinse the probe after use in clean fresh tap water. Then, replace the storage cap/dibber. 

For field testing, repeat the procedure in different locations and take the average of the measured data to represent the pH of the sample area.

Useful resources 

Get started with the Bluelab Soil pH Pen

How to hydrate your Soil pH Pen

How to calibrate your Soil pH Pen

Bluelab pH pen and probe FAQ and troubleshooting 


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