Zone 1b planting calendar
What to plant in April: zone 1b
A rule-of-thumb starting point for zone 1b: last spring frost around June 15, first fall frost around August 15. Zones are set by winter lows, not frost dates, so two gardens in the same zone can be weeks apart. Measure your ZIP below for dates from your area's own 30-year record.
Typical last frost: June 15
Typical first frost: August 15
Winter lows: -55 to -50 °F
Start indoors
- Start onions and leeks indoorsaround Apr 6
Alliums need 10-12 weeks under lights before they go out. The earliest sowing of the year.
Plan & order
- Order fall seedaround Apr 17
Fall brassicas and greens get sown in the heat of summer. Have the seed on hand before that window opens.
Dormant care
- Check season-extension geararound Apr 20
Patch row cover, cold frames and hoops now so a late freeze can't catch you unprepared.
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