This is a condition where the plant cannot absorb or use the nutrients that are available in the soil or water. This can happen if the pH level is too high or too low, or if there is a buildup of salts or minerals in the root zone. A lockout of nutrients can cause symptoms similar to nutrient burn or deficiency, depending on which nutrients are locked out. To fix nutrient lockout, you need to: Stop giving plants nutrients Flush your plants with plain water or a mild nutrient solution to wash away any excess salts or minerals from the root zone. Adjust the pH level of your water or soil to match the optimal range for your plants. For most plants, this is between 5.5 and 6.5 for hydroponic systems, and between 6.0 and 7.0 for soil systems. Feed your plants with balanced cannabis nutrients that contain all the essential elements that they need.