Fall planting calculator

Find the last safe date to sow or transplant a crop so it matures before your first fall frost. The method adds a two-week Fall Factor for slower autumn growth and, for frost-sensitive crops, a two-week Frost-Tender Factor.

Results appear here.

How to use it

Enter your average first fall frost date.
Enter the variety's days to maturity from the packet (choose the earliest-maturing variety for late plantings).
Tick "frost-sensitive" for crops killed by frost; tick "start my own transplants" if you raise seedlings first.

The formula

Days to count back = days to maturity + days from seed to transplant (if you grow your own) + harvest period (optional) + Fall Factor (14 days) + Frost-Tender Factor (14 days, frost-sensitive crops only) Sow-by date = first frost − days to count back Example: 55-day cucumber → 55 + 14 + 14 = 83 days before first frost.

Virginia Cooperative Extension explains that the Fall Factor accounts for slower growth in cooler, shorter days, and that frost-sensitive crops need to mature about two weeks before frost to give a reasonable harvest. Presprouting seeds can trim the Fall Factor by two to five days.

Gear for this job

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Floating row cover — [affiliate link placeholder]
Low-tunnel hoops — [affiliate link placeholder]
Cold frame — [affiliate link placeholder]
Fast-maturing fall seed varieties (seed company program) — [affiliate link placeholder]

Frequently asked questions

What is the Fall Factor?

About two extra weeks added to days to maturity because plants grow more slowly in the cooler, shorter days of late summer and fall (Virginia Cooperative Extension).

Which crops need the Frost-Tender Factor?

Crops killed by frost, such as corn, beans, cucumbers, tomatoes and squash. Hardy crops like kale, spinach, turnips and cabbage do not need it.

My packet says days to maturity from transplant. What do I enter?

Enter the packet number as days to maturity, tick "I start my own transplants" and add the days you grow seedlings indoors. The calculator then gives both a seed-sowing date and a transplant date.

Can I plant later than the result?

Sometimes, if you protect plants with row covers, low tunnels or cold frames, or if your fall is mild. Treat the result as a planning deadline, not a hard rule.

Sources

Last reviewed 2026-10-22. Found an error? Tell us.