Zone 4a planting calendar
What to plant in September — zone 4a
Zone 4a averages its last spring frost around May 20 and its first fall frost around September 20. 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 20
First frost: September 20
Winter lows: -30 to -25 °F
Direct sow for fall
- Radisharound Sep 1
Counts back 30 days from your first frost. Frost-hardy — light freezes sweeten it.
Plant to overwinter
- Garlicaround Sep 6
Cloves go in about two weeks before first frost — they root now, sleep, then bulb next summer.
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