Growth Responses of Two Tomato Varieties to Varying NPK Fertilizer Concentration in a Controlled Environment

The growth response of specific tomato varieties to varying nitrogen-phosphorus-potassium (NPK) concentrations in controlled environments remains underexplored. In this study, we assessed the effect of four NPK 20:20:20 fertilization levels (0 g/L, 0.66 g/L, 1.32 g/L, and 1.98 g/L) on plant height, chlorophyll content, and crop yield on two tomato varieties (Jasper a Cherry variety; and Striped German, an Heirloom variety) grown in a greenhouse setting. The experimental design was completely randomized with three replications, and each plot was irrigated and fertilized weekly for a period of 131 days. Results showed that the Striped German type produced a higher fruit yield (344.79 g) and shorter (57.63 cm) heights than Jasper tomatoes. Also, results indicated that a higher NPK application rate increased tomatoes' chlorophyll content and yield at an optimum rate of 1.32 g/L. Study findings revealed that Striped German tomatoes responded to higher levels of NPK fertilizer, showing that yield increased 234% at 1.32 g/L, and 255% at 1.98 g/L of NPK concentration compared to untreated plants, suggesting that increased fertilizer application can substantially increase tomato production for farmers, especially in controlled environments.