Zone 1a planting calendar

What to plant in March: 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.

Plan & order

  • Map this year's beds2 sowings: Mar 7 and Mar 14

    Rotate families off last year's ground. Nightshades, brassicas and cucurbits each move to a new bed. Sowing again a few weeks later keeps the harvest coming instead of arriving all at once.

Dormant care

  • Sharpen and oil toolsaround Mar 21

    Clean, sharpen and oil blades while there's time. Dull tools bruise plants and slow you down.

Start indoors

  • Sow microgreens indoorsaround Mar 28

    A tray on the windowsill gives you a cut of fresh greens every 10-14 days through the cold months.

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