How does moving a planting change its climate-adjusted harvest date?

Heirloom works out the days to maturity again for the new week, so your harvest date stays true wherever you drag the planting. The first harvest can move by more or less than you moved the planting: sowing two weeks later in a cool spring may bring the harvest less than two weeks later, and a late summer sowing pushed back can slip further.

The harvest window keeps its length and moves with the first harvest. The same happens when you change the Field planting date in the planting window, or update plantings from your Charts. See Use climate-adjusted days to maturity in a planting.