Determining Optimal Nutrient Value through Leaf Tissue Analysis on Tomato

Abstract

The number of vegetable producers using controlled environments and hydroponics for production in the United States has grown significantly in the last decade. There are many different hydroponic nutrient solutions on the market and these solutions have recommended rates of application that are specifically designed to suit the needs of newer hybrid lines. The management of heirloom tomatoes is different as each heirloom line has specific nutritional needs that may require more or less of an individual nutrient than the standard hybrid line. The optimization of Total Dissolved Solids (i.e. fertilizer solution) for each heirloom line is required to achieve the maximum production of saleable fruit. If not optimized, excess fertilization has the potential to become an economic cost and reduce sustainability. Each variety can require a significantly different solution strength in order to reach its maximum potential yield. This work developed methodologies required to determine optimal nutrient plans for three of the tomato varieties being grown at the Tennessee Tech University Oakley Farm greenhouses. Through leaf analysis the tomatoes were tested with an industry standard nutrient package. By testing the leaves, we found that the nutrients were in the normal range for “greenhouse tomatoes”, but it was obvious from observation that the heirloom varieties were all lacking individual nutrients like Calcium, Nitrogen and Magnesium. We feel that further research is necessary utilizing individual nutrients instead of a standard nutrient package to determine the appropriate levels of macro and micronutrients needed for the most popular commercial heirloom varieties.