Answer: Watermelons grow quickly, need warm soil and do not tolerate cold at all so they are planted relatively late. You can start the seeds indoors about two weeks befpre the last expected frost and then set the seedlings in the garden about two weeks after the last frost or you can plant the seeds directly in the garden about a week after all danger of frost is past.
The Q&A section has many entries for all kinds of vegetables, there are also many articles about different vegetables in the Archive. You might also find the following http://plantfacts.ohio-state.edu/ useful as it is searchable and provides lots of detail.
Enjoy your gardening!
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