Zone 1a planting calendar

What to plant in May: 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

  • Pre-sprout seed potatoesaround May 9

    Chit potatoes in a bright, cool spot for 2 weeks. Sprouted pieces jump ahead once planted.

Garden care

  • Wake the beds2 sowings: May 16 and May 23

    Turn in compost, cut down cover crops, and let the soil warm two weeks before the first sowing. Sowing again a few weeks later keeps the harvest coming instead of arriving all at once.

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