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What to plant in May in the Northeast and Midwest

Worked out for 67 cities from their own weather and frost dates, by zone.

What to sow and plant in May in the Northeast and Midwest, by zone: frost-free, highs of 72–82 °F (Philadelphia, Kansas City and 20 more): tomato, bell pepper, zucchini, green beans, cucumber and 20 more; frost-free, highs of 61–72 °F (New York, Chicago and 37 more): peas, radish, beet, tomato, bell pepper and 27 more; frost possible, highs of 61–72 °F (Bismarck, Montpelier and 3 more): peas, radish, beet, tomato, bell pepper and 24 more; frost-free, highs of 50–61 °F (Duluth): broad bean, peas, onion, lettuce, radish and 35 more.

In the Northeast and Midwest, May is spring.

Frost-free, highs of 72–82 °F: Philadelphia, Kansas City, St. Louis, Columbus and 18 more

In May, on average, these cities have highs of 72 to 76 °F and lows of 52 to 59 °F, 4.3 to 7.0 in of rain on 12 to 16 days; the day lasts 14 h 08 min to 14 h 31 min (on the 15th).

No frost in May in 10 years of data: frost-tender crops can go in too, if it is warm enough for them.

HowWhatWhere
start indoors, plant out in JulyTomato, bell pepper, eggplant, chili pepper, moringaall
start indoors, plant out in June or sow directZucchini, watermelon, pumpkin, basil, luffa, okra, peanutall
sow directGreen Beans, sweet corn, arugula, bok choy, borage, chayote, corn, Florence fennel, kiwano, Napa cabbageall
start indoors, plant out in JuneCucumber, melon, achochaall
sow directSoybeanKansas City, St. Louis, Wichita and 7 more

Compared with April: new — green beans and soybean; no longer sown — peas, lettuce, radish, Swiss chard, beet, parsley, cilantro, celeriac and 5 more.

Not starting in May: lettuce (April, sown direct), peas (April, sown direct) and spinach (no month outdoors by these rules) — dates for Peoria.

Ready to harvest in May in Peoria, if sown in the right month: radish (April), arugula (April), dill (April) and mustard greens (April).

Frost-free, highs of 61–72 °F: New York, Chicago, Boston, Minneapolis and 35 more

In May, on average, these cities have highs of 63 to 71 °F and lows of 45 to 55 °F, 3.0 to 6.0 in of rain on 9 to 16 days; the day lasts 14 h 19 min to 15 h 02 min (on the 15th).

No frost in May in 10 years of data: frost-tender crops can go in too, if it is warm enough for them.

HowWhatWhere
sow directBroad bean, cabbage, chickpeaCleveland, Portland, Maine, Bangor and 1 more
sow directPeas, radish, beet, parsley, cilantro, chamomile, dill, mustard greensChicago, Boston, Detroit and 27 more
plant setsOnion, shallotCleveland, Portland, Maine, Bangor and 1 more
sow directLettuce, Swiss chard, kohlrabiRochester, Portland, Maine, Augusta and 2 more
start indoors, plant out in JuneCauliflowerCleveland, Portland, Maine, Bangor and 1 more
start indoors, plant out in JulyTomato, bell pepper, eggplant, chili pepper, moringaall
start indoors, plant out in JuneZucchini, cucumber, melon, watermelon, pumpkin, basil, achocha, luffa, okra, peanutall
sow directGreen BeansNew York, Pittsburgh, Fort Wayne and 4 more
sow direct or start indoors, plant out in JuneSweet Corn, kiwanoall
sow directArugula, bok choy, borage, chayote, corn, Florence fennel, Napa cabbageall
start indoors, plant out in JulyBrussels SproutsCleveland, Portland, Maine, Bangor and 1 more
start indoors, plant out in AugustCeleriac, celeryNew York, Cleveland, Atlantic City and 1 more

Compared with April: new — green beans, borage and corn; no longer sown — spinach, carrot, broccoli, daikon, kale, parsnip and turnip.

Not starting in May: spinach (February, started indoors) — dates for Atlantic City.

Ready to harvest in May in Atlantic City, if sown in the right month: peas (March), spinach (March), lettuce (March), radish (April), carrot (March), Swiss chard (March), beet (March) and arugula (April).

Frost possible, highs of 61–72 °F: Bismarck, Montpelier, Traverse City, Grand Forks and 1 more

In May, on average, these cities have highs of 64 to 69 °F and lows of 44 to 46 °F, 2.6 to 3.5 in of rain on 10 to 14 days; the day lasts 14 h 44 min to 15 h 09 min (on the 15th).

May falls in the frost season: frost-tender crops wait. Average last frost: Bismarck (May 1), Montpelier (May 8), Traverse City (May 2), Grand Forks (May 10) and Rapid City (May 7).

HowWhatWhere
sow directBroad bean, lettuce, cabbage, Swiss chard, chickpea, kohlrabiMontpelier and Traverse City
sow directPeas, radish, beet, parsley, cilantro, arugula, chamomile, dill, mustard greensall
plant setsOnion, shallotMontpelier and Traverse City
start indoors, plant out in JuneCauliflowerMontpelier and Traverse City
start indoors, plant out in JulyTomato, bell pepper, eggplant, chili pepper, Florence fennel, moringaBismarck, Montpelier, Traverse City and 1 more
start indoors, plant out in JuneZucchini, cucumber, melon, watermelon, pumpkin, sweet corn, basil, achocha, bok choy, kiwano, luffa, Napa cabbage, okra, peanutall
start indoors, plant out in JulyBrussels SproutsMontpelier and Traverse City

Compared with April: new — zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, cilantro, basil and 8 more; no longer sown — spinach, celeriac, celery, chayote, daikon, kale, parsnip and turnip.

Not starting in May: green beans (June, sown direct) and spinach (March, started indoors) — dates for Rapid City.

Ready to harvest in May in Rapid City, if sown in the right month: radish (April), arugula (April), dill (April) and mustard greens (April).

Frost-free, highs of 50–61 °F: Duluth

In May, on average, Duluth has highs of 61 °F and lows of 44 °F, 3.3 in of rain on 11 days; the day lasts 15 h 01 min (on the 15th).

No frost in May in 10 years of data: frost-tender crops can go in too, if it is warm enough for them.

HowWhatWhere
sow directBroad bean, peas, lettuce, radish, cabbage, Swiss chard, beet, parsley, cilantro, arugula, bok choy, borage, chamomile, chickpea, dill, Florence fennel, kohlrabi, mustard greens, Napa cabbageDuluth
plant setsOnion, shallotDuluth
start indoors, plant out in JuneCauliflower, zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, basil, achocha, kiwano, luffa, okra, peanutDuluth
start indoors, plant out in JulyTomato, bell pepper, eggplant, Brussels sprouts, chili pepper, moringaDuluth

Compared with April: new — peas, onion, radish, zucchini, cucumber, melon, watermelon, pumpkin and 9 more; no longer sown — celeriac, celery and chayote.

Not starting in May: green beans (June, sown direct) and spinach (March, started indoors) — dates for Duluth.

How we work it out

For each city we use its average weather in May and the months after (highs, lows and rain for 2016–2025, ERA5 reanalysis via Open-Meteo) and its average frost dates. A crop starts in May if the month's mean temperature reaches the minimum soil temperature for germination on its card (we use the mean air temperature as a stand-in for the soil's) and if, over its first months (up to three), the average highs stay within its group's range, with no frost for crops that cannot take it. Crops started indoors count from the month they are planted out.

Temperature groups from Colorado State University Extension: cool-season crops prefer 60–80 °F and lose quality in heat; hardy ones grow in days as cool as 40 °F, semi-hardy ones from 40–50 °F (we use 50 °F); warm-season crops need days above 55 °F, and the most tender (tomato, pepper, eggplant, melon, watermelon, squash) above 60 °F, up to 95 °F. Crops the guide does not name go into the stricter group by their frost hardiness. Fava (broad) beans, which the guide does not name, count as hardy: hardy varieties are sown in fall and overwinter (RHS). Garlic and bulbs: a month before the first frost, and later only while the ground is not frozen (as on each city's page).

Cornell Cooperative Extension sets the season here: hardy crops from about four weeks before the last frost, warm ones after it, heat lovers about 18 days after; the last plantings from 3 weeks (radish) to 16 weeks (melons) before the first frost — counted from each city’s own frost dates.

This is a general rule from averages: your garden can be a week or two earlier or later, and a greenhouse or a cold frame brings the season forward. Greenly works out the dates for your location.

Other months in the Northeast and Midwest