I found a really great online tool that tells you exactly when to start which seedlings, when to harden them off, when to plant them outside. I am so geeked out, I just had to share.
And if you need help finding your spring and fall frost dates, check here.
Happy planning! Or happy scrambling-to-plant-because-you're-late, if you're lucky enough to live in a warmer zone than I (just call me Ms. 3b).