The Field Calculators → Growing
Growing
Last date you can still plant it
Counting backward from first frost, with the correction almost nobody applies — days get shorter, and the crop slows down.
Result
Your average first fall frost2027-10-15
Days to maturity55 days
Short-day correction14 days
Frost toleranceTender — dies at first frost
Sow by
Aug 7
69 days before your first frost.
Expected harvest
Oct 15
Right at frost — cut it fine and you lose it.
Days you're working with
69 days
What this will not do
- The +14 is the whole trick. A 55-day crop sown in August is not a 55-day crop; daylength is falling and so is soil temperature. Skipping this correction is the most common fall-garden failure.
- Hardy greens — kale, spinach, mache, leeks — genuinely improve after frost. Plan the fall garden around them rather than around a second tomato crop.
- Row cover buys roughly 2–4°F, which in October is often two more weeks.
The full build and the reasoning are in Chapter 16 of the guide.