Work backward from frost

Seed-starting date planner

Choose a crop and your local last-frost date to create an indoor sowing and transplant window.

Live worksheet

Tell us what you are working with

Each field explains what to measure, where to find it, and how to read the result. Change any value to update the plan instantly.

CropChoose the crop group whose broad indoor-start pattern you want to view.Example: two tomato varieties can still have different packet instructions.Average last spring frostThe locally reported average date of the final spring freeze. It is a climate planning point, not a frost-free guarantee.Use a nearby weather station or extension source, not a hardiness-zone number.

Start indoorsMar 15, 2026toMar 29, 2026

Transplant windowMay 17, 2026toMay 24, 2026

These are broad planning defaults. The exact variety’s seed packet and local extension guidance should override them.

Sources & further reading

Starting seeds indoorsUniversity of Minnesota Extension

Tell us what you are working with

Build a seed-starting window from a frost-date range

Sources & further reading