Many people dispute if the Tomato is fruit or vegetable and since I plant it in my veggie garden we will deal with it as a vegetable.
Tomato plants need at least 1 1/2 feet between plants, preferably 2 feet, and that's for plants that are grown upright on stakes or cages. Tomato plants should be staked or caged shortly after planting. If no support is given to new plants and they are allowed to sprawl on the ground, tomato plants will need twice as much room. Plants spaced too closely have more disease problems as the foliage stays wet. Plant according to how big they will get so once again the importance of reading labels. Something to consider when selecting tomato varieties Better Boy, Celebrity, and Whopper are resistant to verticillium wilt, fusarium wilt, and root-knot nematodes. If you smoke, wash your hands before touching tomato plants to keep from infecting them with tobacco mosaic virus.
fertilize tomato plants regularly (every 2-3 weeks). Follow the directions given for the particular brand of fertilizer you’re using. Choose fertilizers low in nitrogen to prevent excessive leaf growth but plants that don’t bear fruit. Always try and water early in the day so the plant has time to thoroughly dry. Watering in the evening will leave plants more susceptible to disease.