About & methodology

Planting Calendar is a free tool that tells you when to start seeds, transplant, and harvest common vegetables and herbs — personalized to your location. No sign-up; the math runs in your browser.

How it works

• Your ZIP code maps to an IECC climate zone using the same crosswalk behind our insulation tool (~32,000 ZIPs).
• Each zone has a typical average last spring frost and first fall frost date.
• Each crop is scheduled relative to the last frost: hardy crops (peas, spinach) go in weeks before it; tender crops (tomatoes, basil) start indoors early and transplant after it.

Frost dates are the anchor

Gardeners plant by the last spring frost, not the calendar month. Cold-hardy crops tolerate frost and can be sown early; tender crops must wait until all danger of frost has passed. Getting the frost date right is most of the battle.

Important

These are approximate averages by climate zone. Your exact frost dates depend on local microclimate and elevation, and any given year can run early or late. Always check the forecast before planting out tender crops.