I agree with Jan. Epsom salts are good for the plants. Also, they may be getting leggy because they are too close together. I never put more than one in a large pot. Even when planted in the ground where they have plenty of room to spread, they should be at least 3' apart. I never use commercial fertilizer. Instead I buy one bag of blood meal, one bag of bone meal, and one container of Epsom salts. When mixed together they organically provide everything the commercial fertilizers do. Also, tomatoes love calcium, so sprinkling some powdered milk around the plant every time they're watered provides that, and helps prevent blossom end rot. Hope this helps. ☺
Donna