Nutrient replenishment in hydroponics
Controlling the electrical conductivity (EC) ofrecirculating nutrient solution is a simple and practical way to managenutrient supply in hydroponics, and growers often aim to maintain a target EClevel for a healthy crop. Solution EC is a measure of total soluble salts andprovides an estimate of total nutrients in solution.
Common strategies to control EC include replenishing(i.e. “topping off”) the hydroponic reservoir with fresh nutrient solution andmanaging the strength of the replenishment solution, or topping off with clearwater and frequently monitoring EC and injecting fertilizer as needed. Theresult is the same!
However, maintaining a constant solution EC does not guarantee anadequate, long term nutrient supply.
Check out the e-GRO Alert (EdiblesAlert Volume 6 #11) below on “Fine-tuning nutrient replenishment solutions” for areal-world scenario where maintaining a target solution EC resulted in nutrientdeficiency. The article also discusses a method for designing replenishment solutionsto minimize the risk of nutritional problems and the need to periodically dumpand replace solution.
Fine-tuning nutrient replenishment solutions: http://www.e-gro.org/pdf/E611.pdf
Ryan Dickson
Assistant Professor of Greenhouse and Controlled-Environment Agriculture, University of ArkansasRyan Dickson is a faculty member in the Department of Horticulture at the University of Arkansas. His research program conducts applied research to help horticultural companies problem-solve and overcome production challenges to be more successful and profitable. Major areas of focus include (1) optimizing root zone health for greenhouse edible crops and (2) impoving small fruit production in soilless culture.
