How do I calculate planting dates from my harvest dates?

Lock the harvest date and Heirloom counts back for you, so you hit your first market or CSA week without doing the math. In the planting window, click the lock next to First harvest and set the date you need.

When you then change the days to maturity, Heirloom moves the Field planting date and keeps the harvest where you want it. For a transplant, it also counts back the Days in nursery to give the Nursery start date. The lock is not available while Use climate-adjusted DTM is on.

The steps are in Add a planting.