What to plant in May in Canada

Worked out for 29 cities from their own weather and frost dates, by zone.

What to sow and plant in May in Canada, by zone: frost-free, highs of 16–22 °C (Toronto, Vancouver and 11 more): peas, radish, beet, tomato, bell pepper and 27 more; frost possible, highs of 16–22 °C (Calgary, Winnipeg and 5 more): broad bean, peas, onion, lettuce, radish and 34 more; frost-free, highs of 10–16 °C (Halifax): broad bean, peas, onion, lettuce, radish and 35 more; frost possible, highs of 10–16 °C (Saguenay, Thunder Bay and 4 more): broad bean, peas, onion, spinach, lettuce and 37 more; frost possible, highs below 10 °C (St. John's and Iqaluit): broad bean, peas, onion, spinach, lettuce and 14 more.

In Canada, May is spring.

Frost-free, highs of 16–22 °C: Toronto, Vancouver, Montreal, Ottawa and 9 more

In May, on average, these cities have highs of 17 to 21 °C and lows of 6 to 11 °C, 30 to 104 mm of rain on 6 to 13 days; the day lasts 14 h 34 min to 15 h 23 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.

How	What	Where
sow direct	Broad bean, lettuce, cabbage, Swiss chard, chickpea, kohlrabi	Vancouver, Ottawa, Victoria and 3 more
sow direct	Peas, beet, parsley, cilantro, arugula, chamomile, dill, mustard greens	all
plant sets	Onion, shallot	Vancouver, Ottawa, Victoria and 3 more
sow direct	Radish, borage	Toronto, Vancouver, Montreal and 9 more
start indoors, plant out in June	Cauliflower	Vancouver, Ottawa, Victoria and 3 more
start indoors, plant out in July	Tomato, bell pepper, eggplant, chili pepper, moringa	all
start indoors, plant out in June	Zucchini, cucumber, melon, watermelon, pumpkin, basil, achocha, luffa, okra, peanut	all
sow direct or start indoors, plant out in June	Sweet Corn, bok choy, Napa cabbage	all
sow direct or start indoors, plant out in July	Florence fennel	all
start indoors, plant out in June or sow direct	Kiwano	all
sow direct	Chayote, corn	Toronto, Vancouver, Montreal and 8 more
start indoors, plant out in July	Brussels Sprouts	Vancouver, Ottawa, Victoria and 3 more
start indoors, plant out in August	Celery	Montreal, Ottawa, Hamilton and 3 more
start indoors, plant out in August	Celeriac	Hamilton, London (Canada) and Windsor
sow direct	Daikon	Victoria

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

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

Ready to harvest in May in Kitchener, if sown in the right month: radish (April) and arugula (April).

Frost possible, highs of 16–22 °C: Calgary, Winnipeg, Edmonton, Quebec City and 3 more

In May, on average, these cities have highs of 18 to 19 °C and lows of 4 to 7 °C, 42 to 105 mm of rain on 7 to 14 days; the day lasts 14 h 52 min to 15 h 53 min (on the 15th).

May falls in the frost season: frost-tender crops wait. Average last frost: Calgary (13 May), Winnipeg (12 May), Edmonton (7 May), Quebec City (5 May), Saskatoon (15 May), Sherbrooke (8 May) and Regina (14 May).

How	What	Where
sow direct	Broad bean, peas, radish, cabbage, beet, parsley, cilantro, arugula, chamomile, chickpea, dill, mustard greens	all
plant sets	Onion, shallot	all
sow direct	Lettuce, Swiss chard, kohlrabi	Calgary, Edmonton, Quebec City and 3 more
sow direct	Carrot, broccoli, kale, parsnip	Edmonton
start indoors, plant out in June	Cauliflower, zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, basil, achocha, bok choy, kiwano, luffa, Napa cabbage, peanut	all
start indoors, plant out in July	Tomato, bell pepper, eggplant, Brussels sprouts, chili pepper, Florence fennel, moringa	all
start indoors, plant out in June	Okra	Calgary, Winnipeg, Quebec City and 3 more

Compared with April: new — carrot, zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, cilantro and 11 more; no longer sown — spinach, celeriac, celery, chayote and daikon.

Not starting in May: green beans (July, sown direct) and spinach (August, started indoors) — dates for Edmonton.

Ready to harvest in May in Edmonton, if sown in the right month: radish (April).

Frost-free, highs of 10–16 °C: Halifax

In May, on average, Halifax has highs of 15 °C and lows of 6 °C, 86 mm of rain on 11 days; the day lasts 14 h 48 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.

How	What	Where
sow direct	Broad bean, peas, lettuce, radish, cabbage, Swiss chard, beet, parsley, cilantro, arugula, chamomile, chickpea, daikon, dill, kohlrabi, mustard greens	Halifax
plant sets	Onion, shallot	Halifax
start indoors, plant out in June	Cauliflower, zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, basil, achocha, bok choy, kiwano, luffa, Napa cabbage, okra, peanut	Halifax
start indoors, plant out in July	Tomato, bell pepper, eggplant, Brussels sprouts, chili pepper, Florence fennel, moringa	Halifax

Compared with April: new — zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, cilantro, basil and 12 more; no longer sown — spinach, celeriac, celery, chayote and turnip.

Not starting in May: green beans (July, sown direct) and spinach (September, started indoors) — dates for Halifax.

Ready to harvest in May in Halifax, if sown in the right month: radish (April).

Frost dates in Halifax

Frost possible, highs of 10–16 °C: Saguenay, Thunder Bay, Moncton, Charlottetown and 2 more

In May, on average, these cities have highs of 12 to 16 °C and lows of 1 to 6 °C, 25 to 100 mm of rain on 5 to 12 days; the day lasts 14 h 57 min to 17 h 46 min (on the 15th).

May falls in the frost season: frost-tender crops wait. Average last frost: Saguenay (14 May), Thunder Bay (11 May), Moncton (1 May), Charlottetown (10 May), Whitehorse (18 May) and Yellowknife (23 May).

How	What	Where
sow direct	Broad bean, peas, lettuce, radish, cabbage, Swiss chard, arugula, chamomile	all
plant sets	Onion, shallot	all
sow direct	Spinach, daikon, kale, parsnip	Thunder Bay, Charlottetown, Whitehorse and 1 more
sow direct	Carrot	Thunder Bay, Charlottetown and Whitehorse
sow direct or start indoors, plant out in July	Broccoli	Thunder Bay, Charlottetown, Whitehorse and 1 more
start indoors, plant out in June	Cauliflower	all
sow direct or start indoors, plant out in June	Beet, kohlrabi	all
start indoors, plant out in July	Leek	Whitehorse
start indoors, plant out in July	Tomato, bell pepper, eggplant, chili pepper, Florence fennel, moringa	Saguenay, Thunder Bay, Moncton and 1 more
start indoors, plant out in June	Zucchini, cucumber, melon, watermelon, pumpkin, sweet corn, basil, achocha, bok choy, kiwano, Napa cabbage, peanut	Saguenay, Thunder Bay, Moncton and 2 more
sow direct or start indoors, plant out in July	Parsley	all
sow direct	Cilantro, chickpea	Saguenay and Moncton
start indoors, plant out in July	Brussels Sprouts	all
sow direct	Dill, mustard greens	Saguenay, Thunder Bay, Moncton and 2 more
start indoors, plant out in June	Luffa	Saguenay, Thunder Bay, Moncton and 1 more
start indoors, plant out in June	Okra	Saguenay and Moncton

Compared with April: new — onion, carrot, zucchini, cucumber, melon, watermelon, pumpkin, sweet corn and 15 more; no longer sown — celeriac, celery and chayote.

Not starting in May: green beans (July, sown direct) — dates for Charlottetown.

Frost possible, highs below 10 °C: St. John's and Iqaluit

In May, on average, these cities have highs of -1 to 9 °C and lows of -6 to 2 °C, 32 to 92 mm of rain on 8 to 12 days; the day lasts 15 h 06 min to 18 h 12 min (on the 15th).

May falls in the frost season: frost-tender crops wait. Average last frost: St. John's (19 May).

How	What	Where
sow direct or start indoors, plant out in June	Broad bean, spinach	all
sow direct	Peas, lettuce, radish, turnip	St. John's
plant sets	Onion	St. John's
sow direct or start indoors, plant out in July	Cabbage	all
start indoors, plant out in July	Broccoli, parsley	all
start indoors, plant out in June	Cauliflower, Swiss chard, beet, arugula, chamomile, kale	St. John's
start indoors, plant out in July	Leek, Brussels sprouts	St. John's
start indoors, plant out in June	Kohlrabi	all

Compared with April: new — peas, onion, radish, cauliflower, Swiss chard, beet, arugula, chamomile and 2 more.

Not starting in May: tomato (no month outdoors by these rules), bell pepper (no month outdoors by these rules), zucchini (no month outdoors by these rules) and green beans (no month outdoors by these rules) — dates for Iqaluit.

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 16–27 °C and lose quality in heat; hardy ones grow in days as cool as 4 °C, semi-hardy ones from 4–10 °C (we use 10 °C); warm-season crops need days above 13 °C, and the most tender (tomato, pepper, aubergine, melon, watermelon, squash) above 16 °C, up to 35 °C. Crops the guide does not name go into the stricter group by their frost hardiness. Broad beans, which the guide does not name, count as hardy: hardy varieties are sown in autumn 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).

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.