Choose a fall frost estimate that matches the risk you are willing to take. Check whether your packet counts maturity from sowing or transplanting, then enter that duration and an optional buffer. The calculator subtracts both from your frost date. Shorter days, unusual temperatures and crop variety can delay harvest; the output is not a harvest guarantee.
Fall harvest deadline calculator
Subtract packet days to maturity and your chosen buffer from a frost date. Check whether the packet counts from sowing or transplanting.
These tools calculate from your inputs. Save or print with your browser. Check forecasts, soil conditions and seed-packet instructions before planting.
These calculations use your inputs locally in the browser; they do not infer city frost dates. Read our gardening disclaimer and compare all planting tools.
How to use the fall planting deadline calculator
- Choose a first fall frost date. An earlier date is the safer choice; a later date accepts more risk.
- Find days to maturity on the seed packet and note whether it counts from sowing or from transplanting.
- Enter that number and an optional buffer. A buffer of one to two weeks allows for slower growth as days shorten.
- Read the result as the latest date you should sow or transplant to harvest before frost.
Worked example
If your first fall frost is October 20, a crop needs 60 days, and you add a 14-day buffer, the calculator subtracts 74 days. The latest planting date comes out as August 7. Plant later than that and the crop may not finish before frost.
Things the date cannot tell you
- Growth slows in autumn because days are shorter and the soil cools, so crops often take longer than the packet says.
- Some crops, such as kale and spinach, tolerate light frost, so you may be able to plant them later than a tender crop.
- A frost date is an average. Your yard may differ from the nearest weather station.
See our guide to when to plant a fall garden and the explanation of frost versus freeze.