When should I plant muskmelon and watermelon seeds?

Question:

When should I plant muskmelon and watermelon seeds?

Answer:

Muskmelon and watermelon are warm-season crops.  Plant melons after the danger of frost is past and soil temperatures have warmed to 60 to 70 degrees Fahrenheit.  Melons can be planted in mid-May in central Iowa.  Gardeners in southern Iowa can plant about 1 week earlier.  Plant 1 week later in northern areas of the state.  The last practical date to sow early maturing muskmelon and watermelon varieties is June 20.   

More information can be found in these articles: Growing Watermelon in the Home Garden and Growing Cantaloupe, Muskmelon, and Other Melons in the Home Garden.