Plot · field guide
Your Last Day to Plant a Fall Garden (by Frost Date)
A fall garden is the easy season, fewer pests and sweeter greens, but it comes with a deadline you cannot argue with: the first frost. Plant too late and your crops run out of daylight before they finish. The good news is the last safe day to sow is a number you can calculate, and it is different for every crop and every ZIP code. Here is how to find yours.
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Fall gardens are a race against frost
In spring you plant after the last frost. In fall you plant before the first one, which means the clock is running from the day you sow. Miss the window and a crop simply will not mature in time, and most fall crops then wait until next year.
The whole game is knowing your last safe sow date for each crop. Get that right and fall is the most forgiving season there is.
Count back from your first frost
Take your first fall frost date, subtract the crop's days to maturity, then subtract about two more weeks because growth slows as the days get shorter. What is left is the last day you can sow that crop and still harvest before frost.
Kale needs about 60 days, so from a November 1 frost you count back 60 days plus a buffer and get a last-sow date in late August. Do that for each crop and you have your fall calendar.
The fastest crops buy you the most time
If the calendar is tight, lean on quick crops. Roughly how long each needs:
- Radishes: about 28 days, the fastest fall crop by far.
- Spinach and leaf lettuce: about 42 to 45 days, and they love cool weather.
- Kale: about 60 days, and a frost makes it sweeter.
- Carrots: about 68 days, and they hold in the ground into winter.
- Garlic: not a race at all, it is planted in fall to harvest next summer.
If you already missed the window
A closed window is not a wasted fall. Plant garlic now for a summer harvest, and it is one of the most rewarding crops to grow. A cold frame or a row cover on hoops also buys several weeks and can carry hardy greens like spinach and kale well past the open-garden date.
And if it is truly too late this year, use the time to plan next season so you are ready the week the window opens.
Know your exact deadline
You do not have to do the frost math by hand. Enter your ZIP into PlotToTable and it looks up your first frost date, then flags the closing window for every fall crop, so the last-sow date does not slip past you in the busy end of summer.
It builds the whole fall plan too: what to sow, how much for your household, and when, all timed to your location.
Keep going
Questions, answered straight
Count back from your first fall frost. Subtract the crop's days to maturity, then about two more weeks for slower fall growth. That gives the last safe sow date. It differs by crop and by ZIP, so check yours rather than using one date for everything.
The fastest crops. Radishes finish in about 28 days, spinach and leaf lettuce in about 42 to 45. Kale needs about 60. If even those are past their window, plant garlic now for next summer.
It depends on your first frost date, which varies widely by location. In much of the country late summer is still in time for quick crops. Enter your ZIP to see which crops still have a window and which have closed.
Yes. A cold frame or a row cover over hoops buys several weeks and can carry hardy greens like spinach and kale through light freezes, well after the open garden is done.