I lost this site, and then just recently ran across it again and knew I had to share: It’s the Grow Guide from Weekend Gardener. It’s just what the wanna-be-organized-gardener needs in order to be able to juggle the sowing, hardening, and transplanting dates of a bazillion different veggies:
For spring vegetable garden planning, select the spring season and enter a planning date, your last spring frost date, and your first fall frost date. Sowing, hardening off, and transplanting tasks for spring plantings are calculated for you from these dates.
Follow a similar procedure when planning your fall vegetable garden. Not all vegetable varieties can be grown in the fall garden, but for those that can, their seeds are started in the summer; GrowGuide will tell you which varieties and when to start them.
Neat, huh? Sure beats drawing up spreadsheets and calendars by hand!
You can find out your average last (spring) and first (fall) frost dates by Googling for ‘em, or go to the National Climactic Data Center site and click your state. Unfortunately it opens a document in pdf format instead of html, but it’s very detailed information. And it lists tons of cities per state, rather than just the capital like most sites do, so you can be sure to get closer to your particular microclimate.