What do you like to eat?

Check with your state's Extension Service. Each county should have it's own Cooperative Extension Office which provides free publications and information for the asking. They can also tell you the average last frost date for your area and ideal planting times for specific crops and varieties in your area.

See how detailed this example is: Vegetable Planting and Planning Calendar for Missouri (download the pdf) complete with spring and fall planting dates (underneath the spring planting dates for appropriate crops), how much to plant per person, etc.

Here is an excerpt:
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Just call up the office in your county. Look under the "Government" section (usually blue pages) of your phone book under "Extension". They will have valuable vegetable/gardening tables available specifically for your area determined by universities, and horticultural research scientists have collected data from growing those crops in your state.

trygardening,

You can plant green/yellow/purple beans right now, cucumbers, as well as brassicas (cauliflower, broccoli, cabbage). Might be a bit late for squash, I don't know. Very soon you'll be able to plant lettuce.