Zone 3b planting calendar

What to plant in March: zone 3b

Zone 3b averages its last spring frost around May 25 and its first fall frost around September 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: May 25
First frost: September 15
Winter lows: -35 to -30 °F
Zone 3b Almanac. What growers here actually recorded: sowing weeks, days to first pick, and yields.

Start indoors

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

  • Alliums need 10-12 weeks under lights before they go out. The earliest sowing of the year.

  • Onionaround Mar 16

    10 weeks of indoor growth before your last frost (05-25). Match day-length to your latitude. Long-day north of 37°, short-day south.

  • Leekaround Mar 16

    10 weeks of indoor growth before your last frost (05-25). Plant seedlings deep in a 6 in trench and hill soil up the stem twice during the season. That buried length is the tender white shaft you're growing for.

  • Parsleyaround Mar 30

    8 weeks of indoor growth before your last frost (05-25). Soak seeds 24 hrs before sowing. Cut outer stems and it comes back for years in mild zones.

  • Chivesaround Mar 30

    8 weeks of indoor growth before your last frost (05-25). Divide the clump every 3 years: one plant becomes six with no effort.

  • 8 weeks of indoor growth before your last frost (05-25). Sow thickly in a band and harvest by pulling every other plant: the rest fill in the gap.

  • Lovagearound Mar 30

    8 weeks of indoor growth before your last frost (05-25). Grows 4-6 ft tall once established; give it the back of the bed and divide the crown every few years to keep it productive.

  • Catniparound Mar 30

    8 weeks of indoor growth before your last frost (05-25). Fence it off if cats roam the neighborhood: they'll flatten the plant and any seedlings around it rolling in the scent.

Direct sow

  • Rutabagaaround Mar 2

    Soil is ready -12 weeks before last frost.

  • Daikon Radisharound Mar 30

    Soil is ready -8 weeks before last frost.

Dormant care

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