GreenlyCalgary: frost dates
Canada
In Calgary the last spring frost usually comes around 13 May and the first autumn frost around 1 October, which leaves about 141 frost-free days (median of 2016–2025). Tomato seedlings can go into open ground around 3 June.
| Last spring frost | around 13 May |
|---|---|
| First autumn frost | around 1 October |
| Frost-free days | 141 days |
Median of 2016–2025 for the 25 km grid cell of the city: the last day at or below 0 °C in spring and the first in autumn (ERA5 reanalysis via Open-Meteo). In a cold year a frost can come a week or two later — Greenly warns 48 hours ahead.
When to sow and plant
| Crop | Sow for seedlings | Plant out in a greenhouse | Open ground |
|---|---|---|---|
| Achocha | 20 March | 29 April | 20 May |
| Arugula | — | 1 April | sow 22 April |
| Basil | 20 April | 28 May | 18 June |
| Beet | — | 1 April | sow 22 April |
| Bell Pepper | 15 March | 28 May | 18 June |
| Black-eyed Susan | 19 March | — | 20 May |
| Bok Choy | 25 March | 29 April | 20 May |
| Broad bean | — | 1 April | sow 22 April |
| Broccoli | — | 1 April | sow 22 April |
| Brussels Sprouts | 15 February | 1 April | 22 April |
| Cabbage | — | 1 April | sow 22 April |
| Calendula | — | 1 April | sow 22 April |
| Carrot | — | — | sow 22 April |
| Cauliflower | 18 February | 1 April | 22 April |
| Celeriac | 11 February | 29 April | 20 May |
| Celery | 11 February | 29 April | 20 May |
| Celosia | 31 March | 15 May | 5 June |
| Chamomile | — | 1 April | sow 22 April |
| Chayote | 31 January | 29 April | 20 May |
| Chickpea | — | — | sow 22 April |
| Chili Pepper | 5 April | 18 June | 9 July |
| China aster | 6 April | 28 May | 18 June |
| Chives | — | — | sow 22 April |
| Cilantro | — | 1 April | sow 22 April |
| Corn | — | 29 April | sow 20 May |
| Cosmos | 31 March | 15 May | 5 June |
| Cucumber | 16 April | 28 May | 18 June |
| Daikon | — | 1 April | sow 22 April |
| Delphinium | 22 February | — | 22 April |
| Dill | — | 1 April | sow 22 April |
| Eggplant | 19 March | 28 May | 18 June |
| Florence fennel | 15 March | 29 April | 20 May |
| Garden sorrel | — | 1 April | sow 22 April |
| Green Beans | 23 March | 29 April | 20 May |
| Hyssop | — | — | sow 22 April |
| Kale | — | 1 April | sow 22 April |
| Kiwano | 11 April | 13 May | 3 June |
| Kohlrabi | — | 1 April | sow 22 April |
| Leek | 21 January | 1 April | 22 April |
| Lemon balm | — | 1 April | sow 22 April |
| Lettuce | — | 1 April | sow 22 April |
| Lisianthus | 4 January | 1 April | 22 April |
| Lovage | — | — | sow 22 April |
| Luffa | 16 April | 28 May | 18 June |
| Marigold | 18 March | 29 April | 20 May |
| Melon | 6 April | 28 May | 18 June |
| Microgreens | — | 15 May | sow 5 June |
| Moringa | 24 April | 18 June | 9 July |
| Mustard greens | — | 1 April | sow 22 April |
| Napa cabbage | 27 March | 29 April | 20 May |
| Nasturtium | 22 March | 29 April | 20 May |
| Okra | 16 April | 28 May | 18 June |
| Oregano | 31 January | 1 April | 22 April |
| Pansy | 4 February | 1 April | 22 April |
| Parsley | — | 1 April | sow 22 April |
| Parsnip | — | — | sow 22 April |
| Peanut | 21 April | 28 May | 18 June |
| Peas | — | 1 April | sow 22 April |
| Petunia | 26 March | 28 May | 18 June |
| Physalis | 29 March | 13 May | 3 June |
| Pumpkin | 6 April | 13 May | 3 June |
| Purple coneflower | 19 February | — | 22 April |
| Radish | — | — | sow 22 April |
| Sage | 11 February | 1 April | 22 April |
| Snapdragon | 26 January | 1 April | 22 April |
| Spinach | — | 1 April | sow 22 April |
| Stevia | 25 March | 13 May | 3 June |
| Stock | — | 1 April | sow 22 April |
| Sunflower | — | 15 May | sow 5 June |
| Sweet Corn | — | 29 April | sow 20 May |
| Sweet pea | 18 February | 1 April | 22 April |
| Sweet William | — | — | sow 22 April |
| Swiss Chard | — | 1 April | sow 22 April |
| Thyme | — | 1 April | sow 22 April |
| Tomato | 17 March | 13 May | 3 June |
| Turnip | — | 1 April | sow 22 April |
| Watercress | — | 1 April | sow 22 April |
| Watermelon | 26 April | 28 May | 18 June |
| Zinnia | 14 May | 18 June | 9 July |
| Zucchini | 11 April | 13 May | 3 June |
Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day.
Calgary: weather for the next 7 days
Forecast by Open-Meteo. Nights at or below 0 °C are marked as frost.
Planted in autumn
| Crop | Plant around |
|---|---|
| Bearded Iris | 1 September |
| Crocus | 1 September |
| Daffodil | 1 September |
| Garlic | 1 September |
| Hyacinth | 1 September |
| Lily | 1 September |
| Peony | 1 September |
| Saffron | 1 September |
| Tulip | 1 September |
| Wild garlic | 1 September |
A month before the first autumn frost, so the roots grow before winter.