Safer® Hydro FAQ: How Can I Fix Nutrient Solution That Is Too Acidic?
Getting the pH of your nutrient solution right for your plants and system is crucial because when it is too high (alkaline) or too low (acidic) the roots may not be able to take up all of the essential minerals you are providing.
For instance, calcium – a crucial nutrient for healthy bud development – becomes unavailable to plants when the pH is below 5.5. The ideal pH for plants growing in soil mixes is 6.0 to 6.5. In pure hydroponic systems, 5.5 to 6.0 is the best pH.
If you test your nutrient solution and find it is below those levels, you can buy products from a hydroponic supplier that raise the pH or you can try adding a small amount of ordinary baking soda.
Before you adjust your nutrient solution, check the water that you're using. Distilled water has a neutral pH of 7, but tap water can be lower or higher, depending on how it has been treated (municipal water) or its natural mineral content (well water).