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How do I tell if my PPM/EC is too high or too low?

Cannabis cultivation is both an art and a science. One of the key aspects of growing healthy, high-quality cannabis plants is maintaining the proper nutrient balance in your growing medium. In this article, we will discuss how to determine if the Parts Per Million (PPM) or Electrical Conductivity (EC) of your nutrient solution is too high or too low, and how to adjust accordingly.

What are PPM and EC?​

PPM (parts per million) and EC (electrical conductivity) are measurements used to determine the concentration of dissolved nutrients in a liquid solution. PPM measures the number of nutrient particles per million, while EC measures the ability of the solution to conduct electricity, which is directly related to the concentration of dissolved nutrients. Both PPM and EC are essential indicators of the nutrient levels in your cannabis growing medium.

Ideal PPM and EC Levels for Cannabis​

The ideal PPM and EC levels for cannabis plants vary depending on the stage of growth and the specific strain being cultivated. However, there are general guidelines that can be followed:

  • Seedlings: 100-250 PPM (0.2-0.5 EC)
  • Vegetative stage: 300-800 PPM (0.6-1.6 EC)
  • Flowering stage: 800-1500 PPM (1.6-3.0 EC)
It's essential to monitor and adjust the PPM and EC levels throughout the plant's life cycle to ensure optimal plant health and yield.

Signs of High PPM or EC​

High PPM or EC levels can lead to nutrient toxicity, which can severely harm your cannabis plants. Some common signs of nutrient toxicity include:

  • Leaf tip burn: Brown or yellow tips on the leaves
  • Leaf curling: Upward or downward curling of the leaf edges
  • Stunted growth: Slowed or halted plant growth
  • Dark green leaves: A darker green color than normal
If you notice any of these signs, it's crucial to take immediate action to correct the nutrient imbalance.

Signs of Low PPM or EC​

Low PPM or EC levels can result in nutrient deficiencies, which can also have detrimental effects on your cannabis plants. Some common signs of nutrient deficiencies include:

  • Yellowing leaves: A gradual yellowing of the leaves, often starting from the bottom and moving upwards
  • Weak stems: Stems that are thin and unable to support the plant's weight
  • Slow growth: Slower than usual growth rates
  • Small or weak buds: Reduced bud size and potency
If your plants exhibit any of these symptoms, you should increase the nutrient levels in your growing medium.

How to Adjust PPM or EC​

To adjust the PPM or EC levels in your cannabis growing medium, you will need to either add or remove nutrients. Here are some steps to follow:

  1. Test the PPM or EC of your nutrient solution using a reliable meter.
  2. Compare the readings with the recommended PPM or EC levels for your plant's growth stage.
  3. If the levels are too high, dilute the nutrient solution with water and retest. Repeat this process until the desired levels are reached.
  4. If the levels are too low, gradually increase the nutrient concentrations by adding more nutrients to the solution. Retest and adjust as needed.
Remember that it's better to make small changes and monitor the plant's response than to make drastic adjustments that could cause further harm.


Maintaining the optimal PPM and EC levels in your cannabis growing medium is crucial for healthy plant growth and bountiful yields. By understanding the signs of high and low PPM or EC levels and knowing how to adjust nutrient concentrations accordingly, you can ensure that your cannabis plants receive the proper nutrition they need to thrive.
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