Zone 1a planting calendar

What to plant in March: zone 1a

Zone 1a averages its last spring frost around June 20 and its first fall frost around August 10. 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 20

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 bedsaround Mar 7
Rotate families off last year's ground. Nightshades, brassicas and cucurbits each move to a new bed.
Soil testaround Mar 14
A $20 test now tells you what to amend before planting instead of guessing all season.

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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