One of the most overlooked, but important, aspects of growing healthy plants is pH.
The pH level of your nutrient solution has major implications on your plants’ health, and whether you're growing cannabis or basil it's essential that your nutrient solution falls within the optimal pH range for your plant.
If your pH drifts too high or too low, you may start to see issues with your plant, such as the foliage yellowing, or your plant’s growth being stunted.
- Acidic solutions contain a greater concentration of Hydrogen ions (H+)
- Basic solutions contain a higher concentration of Hydroxyl ions (OH-).
pH scale showing very acidic to very basic solutions (Source)
Why does pH really matter when growing cannabis?
Additionally, certain nutrients, such as calcium, may solidify and fall out of the solution. This is known as scale, and is a white substance that covers the walls of your reservoir and causes your plant’s leaves to yellow, burn and bend.
This image shows the pH levels at which essential nutrients are absorbed best by plants.
You can see that a nutrient like Nitrogen can be amply absorbed within a large pH range (5.0 - 9.0), whereas Phosphorus can only absorbed from pH 5.0 - 6.0 and 9.0 - 10.
However, majority of the nutrients can well absorbed within the pH 5.5 - 6.0 levels. That is why a pH of 5.5 - 6.0 is the optimal range for plants.
Because the absorption of nutrients is so critical to maintaining healthy plants, it is important to measure and adjust your pH daily to avoid any issues.
How to test and adjust pH
There are many ways to test the pH of your hydroponic garden. The options range in both accuracy and price:
2. pH meter - For some extra money, you can get yourself a handheld pH meter that will read and report the pH level digitally. These meters are fairly accurate and will perform much better than pH strips. Not to mention they last more than just one test!
3. Grobo - Unlike both pH strips and a pH meter, Grobo will measure your pH automatically 24 hours a day, meaning you never have to worry about your pH being out of balance. In addition, Grobo will automatically adjust your pH if it is found to be out of balance, eliminating the need to play around with dosing pH up or pH down. As an added bonus, you can grow your plants right in Grobo, and Grobo takes care of all aspects of plant growth for you, including other time consuming tasks like lighting and nutrient dosing!