Regardless of the concentrations of your nutrient solution, unbalanced pH levels can create an antagonistic environment for nutrients and will make them unavailable to your plants. The figure above shows how nutrient availability relates to pH.
Editor’s note: Balancing pH is a critical component to ensuring nutrient solubility and uptake for cannabis. As part of the upcoming release of the Fluence Cannabis Cultivation guide (available later this month), we are releasing tips on how to measure and monitor pH to ensure your fertigation strategy is not a limiting factor to your use of high-intensity LED lighting.
Testing pH is easy. Combination pH/EC meters are relatively inexpensive and require little training to use. They offer a permanent solution to disposable pH test strips and dye kits, which are cumbersome and must be subjectively interpreted by the color of the reactive test material.
05 Mar Best Practices for Monitoring pH for Cannabis
Caption: Nutrient availability increases or decreases in response to pH. A pH level of 5.8 – 6.2 is appropriate for cannabis.
Cannabis, like many plants, prefers slightly acidic soil conditions. It tolerates a wide pH range (5.0-7.0) without symptoms of bronzing or interveinal chlorosis (yellowing of top leaves), but pH levels outside of the optimal range of 5.8 – 6.2 will limit growth. To maintain optimal pH levels, cultivators should test pH levels every two days, and adjust the pH as needed.
We hope these tips have been a helpful reminder of how to leverage pH tests in your grow.
For example, when pH is low, the solubility of some micronutrients like iron and manganese increases, making them more available to plants. This can cause toxicity. However, when pH increases, micronutrients, along with phosphorus, become less soluble and less available to plants.