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Creating the optimal environment for your cannabis plants will allow them to grow as best they can. This optimal environment includes having the right pH in your feeding water, soil, or growing medium. Paying attention to the pH will help give your plants healthy leaves and avoid nutrient lockout. To keep track of pH levels you will need a pH tester or pH meter. 

    

What is a pH Meter?

A pH meter is an electronic device that measures how acidic or alkaline something is. This measurement is also known as the pH. Solutions with a pH of over 7 are acidic whereas solutions with a pH below 7 are alkaline. 

A pH meter consists of a special measuring probe attached to an electronic meter that displays the decimal pH reading. The pH meter will need to be calibrated before used to test your solution.

 

                                                                                                   

  

What is the Difference Between a pH Meter and Other Types of Meters?

There are many types of meters available which all measure something different. A pH meter is different to other tester pens. Here is a guideline to help you know what these other types of pens are:

 

pH Pen - measures the pH (acidity or alkalinity) of a liquid

TDS Meter - measures Total Dissolved Solids in a liquid. This is the same as a ppm meter.

PPM Meter - This is another name for a TDS meter

EC Meter - measures the electrical conductivity of a liquid. 

      

Who Should Use a pH Pen?

A pH pen is a great tool for growers, however not all growers will need the precision a pH test offers. 

Soil Growers

If you are using amended soil, a pH pen might not do you much good as you should hopefully have a system of micro-organisms already taking care of that. 

If you are using soil as a medium and feeding nutrients throughout the grow, then it is recommended to check the pH a bit more. 

Coco Coir/Peat/Perlite/Vermiculite

pH pens are great for growers using these mediums if they are trying to fine-tune their grow or root out a problem that may be pH related. For newer growers using this medium, a pH pen is not a necessity. New growers can use pH test strips or drops for their first grow as this gives more room for variation and is good for learning how plants react. 

DWC or Any Water-Based Hydroponics

A pH pen is a great tool for hydro growers. In mediums where the plants roots are resting in water, it is extremely important to know the pH. This is because water can change the pH much quicker than soil or coco. Using a pH pen can help you keep track of the pH and how it changes so that you are more aware of any problems that may occur and react before they cause any further problems for your plants.

     

How to Use a pH Pen

When using a pH meter there are three main parts. Calibration, measuring and clean and store. Luckily the first part only needs to be done the first time you use it, from then you will only need to calibrate the pH pen every once in a while, once a week is more than enough. 

Calibration

The first step when using your pH pen is to make sure it is calibrated. This will ensure that you get accurate readings. Calibrating your pen and making sure it stays accurate is by far the most unappealing part of owning a pH pen but if you can get past this small step then you're all set.  

To calibrate your pH pen you will need a liquid with a known pH. This is known as a calibration solution and is most often available in pH 4.01 and pH 7.01. 

If you test the liquid and the reading is off, you will need to adjust it until the reading matches the pH of the calibration solution. Some pens will have to be manually dialled in whereas other testers can automatically calibrate themselves once in the appropriate mode. These automatic testers will generally cost more than manual testers because of this feature.

How to Calibrate Your pH Pen

Step 1: The first most important step is to check the specific instructions that came with the device.

Step 2: Pour some 4.01 testing solution into a clean container.

Step 3: Turn your pH pen on and place the electrode into the 4.01 solution you poured out. If the reading does not match 4.01, turn the appropriate dial or button until the screen reads exactly 4.01.

Step 4: Gently clean the electrode with a paper towel and repeat steps 2 and 3 with the 7.01 testing solution.

Step 5: Once the readings match both 4.01 and 7.01 you're done! Do this again in a week to make sure the readings are accurate. 

   

Measuring pH

Now comes the easy part! Just turn the pen on and dip the electrode into the liquid you want to test. Take note that not all pH pens are waterproof, so don't submerge the pH pen completely unless it specifically says that it is waterproof.

Step 1: Remove the protective cap and turn on the pen.

Step 2: Place the electrode into the liquid you want to test and leave it in until the reading stays within a .02 range. You can speed this process up by lightly swirling the electrode through the water. 

Step 3: Make sure you only give your plants water in the correct range. 

 

Hydro: pH of 5.5 to 6.5

Soil: pH 6.0 to 7.0

   

Cleaning and Storage

Once you are finished using your pH pen, it is important to never put your pen away with the electrode dry. Storage Solution For pH Electrodes is necessary for storing a pH electrode in order to keep the glass membrane of the pH electrode hydrated. Dryness can break the electrode.

Step 1: Rinse off the electrode with a small amount of cleaning solution. 

Step 2: Pour a small amount of storage solution into the protective cap of your pH pen. Make sure there is enough in the cap to cover the electrode when the pen is placed in.

Step 3: Place the pen in the protective cap so that it stays hydrated.

Step 4: Don't forget to turn it off so that you can save the batteries. 

  

Some Final Notes on Using pH Meters in Cannabis Growing

Now that you know how to properly calibrate, use and store a pH meter, you can decide if it is something you want to invest in for your grow. Having the right pH in your water or soil is extremely important as a pH that not in the optimal range will have negative effects on your plants growth and the way it takes in nutrients. You can use pH testing strips and drops, however for some growers, especially hydro growers, a pH pen is a better option.