Planting guide

What to plant in Zone 4 in May

USDA Zone 4 · US Northern Hemisphere May

In zone 4 the season opens in May, and most of the month belongs to the cool-season crops. The average last freeze falls between May 7 and May 10 at NOAA's stations in Fargo, Bismarck, Helena and Caribou, Maine, and one year in ten there is still a freeze after May 23 to 25. So hardy crops go in early in the month, and tender ones wait for the end of it or for June.

Plant now

Peas, spinach, radish, turnips, onions, potatoes (first days of the month)

Hardy crops that take a hard frost. Extension calendars put them in the ground weeks before the last frost, so if they are not in yet, plant them now.

Broccoli, cabbage, kale and kohlrabi transplants (early in the month)

Safe to set out from four weeks before the last frost, so they can go out at once.

Lettuce, beets, carrots, chard (first half of the month)

Semi-hardy: they tolerate a light frost and are planted two to four weeks before the last one, which was mid to late April by the average date, so sow them now.

Bush beans and sweet corn (late in the month)

Tender. Sow after your average last frost and only once the soil has reached 60°F (16°C).

Tomato transplants (late in the month, or early June)

Safe one to two weeks after the last frost, with nights at 50°F (10°C) or warmer: mid to late May by the average date, early June if you plan around the one-year-in-ten freeze.

Cucumbers, squash and melons (seed indoors now)

They go out two weeks after the last frost and take three to four weeks from seed, so sow them indoors in the first half of May for an early June plant-out.

Timing notes

  • Peppers and eggplant should stay inside this month. They are very tender: at least two weeks after the last frost, with nights of 60-65°F (16-18°C).
  • Memorial Day is a cautious all-clear: the University of New Hampshire Extension uses it as a conservative last frost date for central New Hampshire, and it sits at or just after the one-year-in-ten freeze date at the stations above.
  • Look up the average last frost for your own town with the frost date calculator; the zone number is a winter-minimum band, not a planting date.
Frost dates and a seed-starting schedule for your ZIP code Free calculator from NOAA station records: last spring frost, first fall frost, and what to start each week. ← All planting guides