EC (Electrical Conductivity) measures the ability of a solution to conduct electricity, which is directly related to the concentration of dissolved salts (nutrients) in the water. It is measured in millisiemens per centimeter (mS/cm).

PPM (Parts Per Million) is a measure of the concentration of nutrients in the water. The EC value can be converted to PPM using a conversion factor. The most common conversion factors are:

• 500 (NaCl): Based on the conductivity of a sodium chloride (table salt) solution. Commonly used in horticulture.
• 700 (442): Based on a mixture of 40% sodium sulfate, 40% sodium bicarbonate, and 20% sodium chloride, closer to natural water composition.

EC/PPM Levels for Cannabis

Maintaining proper EC/PPM levels is crucial for cannabis plant health and yield. General guidelines:

• Seedlings: EC 0.4-0.6 (200-300 PPM)
• Vegetative Stage: EC 1.2-1.6 (600-800 PPM)
• Flowering Stage: EC 1.8-2.2 (900-1100 PPM)
• Late Flowering Stage: EC 2.0-2.4 (1000-1200 PPM)

Note: These values are guidelines and can vary depending on the strain and growing conditions. Always monitor your plants and adjust accordingly.