If you’ve been wondering when to start your seeds indoors, take a look at Botanical Interests’ Indoor Seed Sowing guide. This handy chart walks you through planning to have your seedlings ready in time for planting.
If you’re unsure of when you should plant out, Fedco Seeds has a very thorough chart that includes dates for setting out. Please note that if you live at elevation, or in far northern areas, you should go by soil temperatures needed for planting out, rather than a fixed date.
Gardeners in Colorado can check out this timetable for seed starting, written for Colorado State University Extension by Dr. Steven Newman.