Zone 1b planting calendar

What to plant in April: zone 1b

Zone 1b averages its last spring frost around June 15 and its first fall frost around August 15. Everything below is timed from those two dates, so it stays useful whether you're planting for summer or for a fall harvest.

These are zone-average dates. Check an area-level frost estimate from thirty years of nearby weather history and this calendar retimes itself.

Last frost: June 15

First frost: August 15

Winter lows: -55 to -50 °F

Zone 1b Almanac. What growers here actually recorded: sowing weeks, days to first pick, and yields.

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.

Turn this into your own calendar

Want this calendar emailed to you?

Get the full 12-month version for your ZIP area. Every sowing, transplant, and harvest window, with reminders you can add to your calendar.

Build my free plan Find my zone & frost dates