Managing your pH is very important when growing hydroponically.  It is critical for pH to remain in the range of 5.0-6.0 with an absolute maximum of 6.5.  At these levels nutrients will remain dissolved in the nutrient solution and therefore available for uptake by the root system.  If the pH of the nutrient solution is higher than 7.0 some of the important elements can precipitate and become unavailable to the roots.  This can cause plumbing blockages as the elements precipitate out of the nutrient solution.  As for the other side of the pH scale, lower pH levels tend to have little affect on the stability of the nutrient solution. Adjusting your pH and knowing when to do it is also imperative to a successful crop cycle.

The pH should be adjusted on a few different occasions.  First, it should be adjusted when the nutrient solution is first made.  Second, the pH should be adjusted after topping off the nutrient solution with water or additives, especially if they are highly alkaline.  Lastly, in a re-circulating system, pH should be checked on a daily basis because the uptake of water and nutrients causes pH to change.  There are a few different ways to minimize the fluctuations in you pH of your nutrient solution.

The first way to minimize the pH fluctuations in your nutrient reservoir is to use a brand that is pH buffered, especially when using highly alkaline water.  The other thing that you should do is to supply two gallons of nutrient per large plant.  If you don’t do this, your pH fluctuations will be greater, particularly during the hot and dry months where water uptake and evaporation are excessive.

Article by, Brett McCormick, co-founder of Good Green Builders.  Good Green Builders is a hydroponic grow room/ greenhouse builder in the San Francisco Bay Area.  For more information or a free consultation, call today, (415) 246-8055.