Johnny's Selected Seeds (no affiliation) provides a range of planting tools and calculators on their website.
The two calculators below help you plan when to plant seeds and seedlings so that your crops will be ready to harvest *before* fall frosts. This is for plants growing outdoors and unprotected. Covering crops or growing them in greenhouses, and choosing frost-tolerant varieties, will extend the season.
Fall-Harvest Planting Calculator
Johnny's Selected Seeds' Fall-Harvest Planting Calculator lets you enter your region's first average frost date (first frost each fall), and works backwards to tell you when you need to start seeds in order for your crops to be ready to harvest before fall frosts, without protection. The dates given are dates transplants (TP) should be set out or seeds should be direct sown (DS) outdoors.
Downloadable spreadsheet from Johnny's Selected Seeds:
Fall-Harvest Planting Calculator
Succession-Planting Calculator
Johnny's Selected Seeds' Succession-Planting Calculator lets you enter your first average frost date, as well as your variety's days to maturity and preferred intervals between plantings. It then calculates a planting schedule for you, ensuring enough time for crops to ripen, unprotected, before fall frosts.
Downloadable spreadsheet from Johnny's Selected Seeds:
Succession-Planting Calculator
