Zone 4a planting calendar

What to plant in May: zone 4a

Zone 4a averages its last spring frost around May 20 and its first fall frost around September 20. 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 20

First frost: September 20

Winter lows: -30 to -25 °F

Zone 4a Almanac. What growers here actually recorded: sowing weeks, days to first pick, and yields.

Transplant out

Lettucearound May 6
Goes out 2 weeks before last frost. It takes the cold.
Onionaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Parsleyaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Mintaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Cabbagearound May 6
Goes out 2 weeks before last frost. It takes the cold.
Caulifloweraround May 6
Goes out 2 weeks before last frost. It takes the cold.
Swiss Chardaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Collardsaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Leekaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Napa Cabbagearound May 6
Goes out 2 weeks before last frost. It takes the cold.
Romanescoaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Endivearound May 6
Goes out 2 weeks before last frost. It takes the cold.
Escarolearound May 6
Goes out 2 weeks before last frost. It takes the cold.
Radicchioaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Sorrelaround May 6
Goes out 2 weeks before last frost. It takes the cold.
Bulb Fennel (Florence Fennel)around May 6
Goes out 2 weeks before last frost. It takes the cold.
Chamomile (German)around May 6
Goes out 2 weeks before last frost. It takes the cold.

Direct sow

Potatoaround May 6
Soil is ready -2 weeks before last frost.
Cilantroaround May 6
Soil is ready -2 weeks before last frost.
Parsleyaround May 6
Soil is ready -2 weeks before last frost.
Swiss Chardaround May 6
Soil is ready -2 weeks before last frost.
Collardsaround May 6
Soil is ready -2 weeks before last frost.
Burdock (Gobo)around May 6
Soil is ready -2 weeks before last frost.
Bulb Fennel (Florence Fennel)around May 6
Soil is ready -2 weeks before last frost.
Chamomile (German)around May 6
Soil is ready -2 weeks before last frost.
Carawayaround May 6
Soil is ready -2 weeks before last frost.
Quinoaaround May 13
Soil is ready -1 weeks before last frost.
Dillaround May 20
Soil is ready 0 weeks after last frost.
Bush beanaround May 27
Soil is ready 1 weeks after last frost.
Cucumberaround May 27
Soil is ready 1 weeks after last frost.
Scarlet Runner Beanaround May 27
Soil is ready 1 weeks after last frost.
Dry Bush Beanaround May 27
Soil is ready 1 weeks after last frost.
Sunflower (Seed)around May 27
Soil is ready 1 weeks after last frost.
Summer Savoryaround May 27
Soil is ready 1 weeks after last frost.
Boragearound May 27
Soil is ready 1 weeks after last frost.
Shiso (Perilla)around May 27
Soil is ready 1 weeks after last frost.

Plan & order

Order fall seedaround May 23
Fall brassicas and greens get sown in the heat of summer. Have the seed on hand before that window opens.

Start indoors for fall

Broccoliaround May 26
Fall broccoli window opens. Sow trays any time in the next four weeks.

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