Zone 1a planting calendar

What to plant in April: zone 1a

A rule-of-thumb starting point for zone 1a: last spring frost around June 20, first fall frost around August 10. 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.

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

Typical last frost: June 20

Typical first frost: August 10

Winter lows: -60 to -55 °F

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

Dormant care

Prune dormant fruit treesaround Apr 4
Prune apples, pears and peaches while fully dormant. Open the center, remove crossing wood.
Check season-extension geararound Apr 25
Patch row cover, cold frames and hoops now so a late freeze can't catch you unprepared.

Start indoors

Start onions and leeks indoorsaround Apr 11
Alliums need 10-12 weeks under lights before they go out. The earliest sowing of the year.

Plan & order

Order fall seedaround Apr 12
Fall brassicas and greens get sown in the heat of summer. Have the seed on hand before that window opens.

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