Growing healthy cannabis plants starts with getting the water right. Two key factors to pay attention to are the pH and electrical conductivity (EC) of your water. Maintaining the proper pH and EC levels will ensure your plants can absorb the critical nutrients they need. In this post, we’ll break down what pH and EC are, why they matter for cannabis cultivation, and how to manage them.
What is pH?
pH is a measure of how acidic or alkaline a solution is. It ranges from 0 to 14, with 0 being the most acidic, 7 being neutral, and 14 being the most alkaline or basic. Cannabis plants prefer a slightly acidic pH in the range of 5.5 to 6.5. Outside of this optimal range, plants have a harder time absorbing nutrients. If the pH drifts too low or too high, you may notice signs of nutrient deficiencies.
The pH level impacts the availability of nutrient ions in the root zone. At lower pH levels, micronutrients like iron, boron, and copper are more available. At higher pH levels, macronutrients like nitrogen, phosphorus, and potassium are more available. Keeping the pH within the target range ensures plants can access all essential nutrients.
Why EC Matters
EC (electrical conductivity) measures the amount of dissolved salts or ions in water. It indicates the total dissolved solids (TDS) and nutrient content. EC is given in units of microSiemens per centimeter (μS/cm).
Cannabis plants need nutrients like nitrogen, phosphorus, and potassium to thrive. Fertilizers provide these macro and micronutrients. However, too many dissolved salts can cause overfertilization, leading to nutrient toxicity and salt buildup. An EC that’s too high can also create water stress for your plants.
Ideal EC levels vary by cannabis growth stage:
Seedlings: EC of 0.2 – 0.5 mS/cm
Vegetative stage: EC of 1.0 – 2.0 mS/cm
Flowering stage: EC of 1.5 – 2.5 mS/cm
Monitoring your irrigation water and nutrient solutions will allow you to modify fertilizer strength as needed.
How to Manage pH and EC
Here are some tips for controlling the pH and EC of your cannabis irrigation water:
Test levels frequently – Use a pH pen and EC meter to monitor your water reservoir. Test daily or before mixing new nutrient solutions.
Modify nutrient strength – For hydroponics systems, increase or decrease fertilizer amounts to reach target EC levels.
Use pH adjusters – Nutrient pH Up and pH Down solutions can tweak pH without impacting EC. Add small amounts at a time.
Filter water – Reverse osmosis filters remove impurities and dissolved solids to give a consistent baseline.
Flush systems – Flush hydro systems with fresh water if nutrient salt buildup gets too high.
With some careful monitoring and adjustments, you can maintain the optimal pH and EC ranges for healthy cannabis. This will support proper nutrient absorption and delicious yields. Let your plants thrive with a well-balanced water diet.
In our previous articles on Easy Cannabis Strains for New Growers, How Long Does It Take To Fully Grow A Cannabis Plant?, and The Economics of Home Cannabis Cultivation: Maximizing Savings and Yield, we discuss various strategies for growing cannabis.