I am starting a vegetable garden, and I need help with how many seeds to plant per crop?

[quizicalgal]

I am growing tomatoes, lettuce, spinach, turnips, peas, lima beans, squash, and watermelon. I know I need to plant a certain # of seeds per plant, but there is no info on the seed packets, and I can't find the answer anywhere online. Any help would be greatly appreciated. ThankS!