What information can you give me on factors that affect the flavor of my tomatoes?

G.C.MissouriAnswer: Thank you for your recent request for information from ATTRA, the National Sustainable Agriculture Information Service regarding factors that affect tomato flavor.Nutrients:A recent article from the University of Wisconsin e-Extension web site says that high levels of soil phosphorus have been shown to increase sugar concentrations of fruits and vegetables while decreasing acidity. “High levels of soil potassium often have a positive effect on the quality of vegetables. Increased soil potassium concentrations have been shown to increase the vitamin C and titratable acidity concentrations of vegetables and improve vegetable color. Potassium also decreases blotchy ripening of tomato (Silva, 2008).” In contrast, too much nitrogen may lower fruit sugar content and acidity in tomatoes. I have enclosed an article that describes the different nutrient factors that affect tomato flavor. Varietal influence:As you are aware the varieties of tomatoes also influence their flavor. Certain varieties are more suited for the longer-term storage that is essential for marketing to larger wholesale outlets. Other varieties may optimize taste, essential for the post harvest quality of vegetables going to farmers markets or CSA’s.When planning which vegetable varieties to grow on your farm, it is important to consider which harvest windows are needed. Vegetables harvested at the incorrect stage of maturity will have a significant decrease in postharvest quality. Quality characteristics such as texture, fiber and consistency are greatly affected by stage of maturity at harvest. This is the case with many store-bought tomatoes. They are harvested at the Open-pollinated (or heirloom) tomatoes generally offer the richest flavors, plus you can save their seeds to plant in future seasons. Hybrid tomato breeding focuses on the needs of commercial producers who favor tomatoes that resist diseases and ship well, often allowing flavor to take a back seat.That being said, there are plenty of hybrid tomatoes that combine good flavor with disease resistance. Reference below is an article from Mother Earth News that describes their survey of growers that rated their “best tasting” heirloom and hybrid tomato varieties. This list may help with your seed order next season.Another factor to consider pre-harvest, is the amount of water your tomatoes are getting. Adequate soil moisture during this period is essential for the maintenance of postharvest quality. Water stress during the growing season can affect the size of the fruit, and lead to soft or dehydrated fruit that is more prone during storage.Resources: Silva, E. 2008. Influence of preharvest factors on postharvest quality. In Wholesale success: a farmer’s guide to selling, postharvest handling, and packing produce (Midwest edition). http://www.extension.org/pages/18363/influence-of-preharvest-factors-on-postharvest-qualityMikkelsen, R.L. 2005. Tomato Flavor and Plant Nutrition: a Brief Review. Better Crops. Volume 89; No. 2.Pleasant, Barbara. 2008. America’s Favorite Tomatoes. Mother Earth News. Feb.March 2008. Downloaded August 2010. http://www.motherearthnews.com/Organic-Gardening/2008-02-01/Americas-Favorite-Tomatoes.aspx