Zone 4b planting calendar
What to plant in September — zone 4b
Zone 4b averages its last spring frost around May 15 and its first fall frost around September 25. Everything below is timed from those two dates, so it stays useful whether you're planting for summer or for a fall harvest.
Last frost: May 15
First frost: September 25
Winter lows: -25 to -20 °F
Direct sow for fall
- Radisharound Sep 6
Counts back 30 days from your first frost. Frost-hardy — light freezes sweeten it.
Plant to overwinter
- Garlicaround Sep 11
Cloves go in about two weeks before first frost — they root now, sleep, then bulb next summer.
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