In 2021 a local small-scale greenhouse operator in Nicholas County had experienced some issues with productivity, health, and overall appearance of greenhouse plants that the grower attributed without evidence to the municipal water source; claimed that it reeked of chlorine. The grower was advised by the UK Plant Disease Diagnostic Laboratory that his problem was more likely due to elevated soluble-salt concentration in his media resulting from overapplication of Epsom salts. In 2022, the grower switched his irrigation water source to a rain-fed cistern that supplies his domestic water for household use, but he continued to experience the same issues in the greenhouse that he had the previous year. In collaboration with Russ Muntifering, Extension Agent for Nicholas County, we helped the grower perform a little side-by-side experiment comparing much more conservative (monthly) vs. very generous use of Epsom salts as he had been doing the past two years. The grower was able to see for himself that his soluble-salt problem was not due to the municipal water supply, but rather to overapplication of Epsom salts.

This producer’s operation does not have an injection system, and he and his family for the past 5 years had been watering and fertilizing out of plastic buckets and empty milk jugs. We checked nutrient ratios in his liquid fertilizer mix that consisted of several sources that they had been measuring painstakingly in ounces, teaspoons and tablespoons of product, and compositing these into a single fertilizer ‘cocktail.’ We have since taught him how to simplify his operation by using a single commercial granular fertilizer for which the nutrient ratios are well aligned with nutrient requirements of the species that he grows. The operator is very happy with this more science-based, simplified and efficient approach to nutrient management, and Epsom salts are now applied very conservatively only once monthly. Furthermore, we taught him how to use a pH meter and properly interpret water and media analyses, and we are currently instructing him in elementary concepts of soil-solution chemistry; e.g., acid/base equilibria, buffering, cation exchange capacity and electrical conductivity.