My tomatoes do not get big. Look like cherry tomatoes.
The soil is watered; food, epsom salt. I have 1 Early Girl and 2 Beef Steak.
Epsom salt is a good source of magnesium but little else. Tomatoes are known "heavy feeders" and need fertilizer with the NPK values. Tomato Tone is one example of an organic fertilizer. "Bloom booster" type fertilizers are also acceptable. https://www.gardeningknowhow.com/.../tomato/tomato-fertilizer.htm