Tools · Fall garden
Fall planting calculator: when to plant for a harvest before frost
Enter your first fall frost date and the crop's days to maturity. The calculator counts back to the last day to plant, with time for slower growth as the days shorten.
Enter your first frost date and the days to maturity to see your planting date.
- Plant by
- —
- Start seed indoors by
- —
How the count works
The calculator follows Virginia Cooperative Extension's method for fall gardens. It counts back from the first fall frost by adding up:
- Days to maturity, from the seed packet or plant tag.
- Days of harvest, how long you want to keep picking.
- A fall factor of 14 days. Crops grow more slowly in the shorter, cooler days of fall than the packet assumes. Maryland Extension uses the same two weeks.
- A frost-tender factor of 14 days, only for crops that frost kills. They need to mature about two weeks before frost to give a reasonable harvest.
- Days from sowing to transplanting, only if you grow your own transplants. That gives the date to start seed indoors.
Example: with a first frost on October 15, a frost-hardy crop at 55 days to maturity and 10 days of harvest counts back 79 days, so sow by July 28.
Reading days to maturity
Check where the count starts. For root crops, days to maturity usually count from sowing; for broccoli and cabbage, they commonly count from transplanting. Check the supplier's definition. If you raise your own transplants, the calculator adds the time from sowing to transplanting on top.
Which frost date to use
Your average first frost date is the 50% date: in about half of years, frost comes earlier. For a crop that frost kills, planning from the earlier 10% date leaves a wider margin. The frost date lookup gives both, and carries the date into this calculator.
Crops that tolerate frost do not stop at the first frost. Very hardy crops such as kale and spinach keep going into the mid-20s °F, so the frost date is a planning point for them rather than an end date. See how cold each crop can take.
What to plant for fall
The calculator gives the latest date; whether a crop suits the time left is a separate question. The August guide covers fall crops that fit a short season, and the July guide covers getting seed up in summer heat.
Sources
- Virginia Cooperative Extension: Fall vegetable gardening (426-334) — the count-back method, fall factor, and frost-tender factor.
- University of Maryland Extension: Fall vegetable gardening — the same 14-day allowance for shorter, cooler days.
- Iowa State University Extension: Guide to starting seed indoors — weeks from sowing to transplanting.