How do I plant tomatoes?
Plant deep, at least to the level of the original seed leaves, or even to the topmost couple of pairs of leaves. (More on how, and how deep, here.) Water in well, applying first of two doses of liquid feed; see below under “Douse each plant’s root zone,” for details.
Space plants at least 2 feet apart in each direction; 3 or more would be much better, as air circulation is another disease-preventive tactic. Caged plants need wider spacing than staked, and indeterminate varieties more than some determinate; plan accordingly.