Alberta Garden Guide: Planting Dates, Frost Dates & Growing Season
Alberta’s short summers require fast-maturing varieties and frost awareness.
In a typical year, the growing season in Alberta runs roughly from May 21 through September 17, leaving about 119 frost-free days in many parts of the province. Use this page as a provincial baseline, then compare city pages for more local planting timing.
Growing Season Snapshot
Alberta gardens often succeed by treating the season as a quick-building, quick-closing window rather than a long gradual runway. Strong summer light helps a lot, but cool nights, local exposure, and a surprisingly sharp late-season drop mean maturity speed and shelter usually matter more than slight differences in planting date.
These season boundaries are climate normals, not a forecast. A 50% frost date means a 32°F frost arrives by that date in about half of years — and later in about half. Treat these dates as planning anchors, not guarantees.
Alberta Planting Calendar
A practical guide to when planting usually works in Alberta. These windows are based on climate normals (not a forecast) and line up with the 50% last spring frost and typical early-season heat.
| Crop | Planting Window | Method |
|---|---|---|
| Cool-season / early window Cold-tolerant crops that usually handle cooler spring conditions better. | ||
| Peas | April 23 – May 7 | direct sow |
| Spinach | April 23 – May 7 | direct sow |
| Lettuce | April 30 – May 14 | direct sow / transplant |
| Strawberries | April 30 – May 14 | plant crowns / transplants |
| Carrots | April 30 – May 14 | direct sow |
| Beets | April 30 – May 14 | direct sow |
| Radishes | April 23 – May 7 | direct sow |
| Potatoes | May 7 – May 21 | plant seed potatoes |
| Onions | April 30 – May 14 | sets / transplants |
| Garlic | May 2 – May 12 | plant cloves |
| Broccoli | May 7 – May 21 | transplant |
| Cauliflower | May 7 – May 21 | transplant |
| Cabbage | May 7 – May 21 | transplant |
| Kale | April 27 – May 17 | direct sow / transplant |
| Swiss chard | May 1 – May 21 | direct sow / transplant |
| Main warm-season window Crops that usually do best once frost risk fades and the season starts opening up more fully. | ||
| Beans | May 21 – June 4 | direct sow |
| Sweet corn | May 26 – June 5 | direct sow |
| Cucumbers | May 30 – June 9 | direct sow / transplant |
| Zucchini | May 30 – June 9 | direct sow / transplant |
| Squash | May 30 – June 9 | direct sow / transplant |
| Melons | May 30 – June 9 | direct sow / transplant |
| Watermelons | May 30 – June 9 | direct sow / transplant |
| Basil | May 30 – June 9 | direct sow / transplant |
| Tomatoes | May 30 – June 9 | transplant |
| Peppers | June 6 – June 16 | transplant |
How to use this: aim for the earlier part of each window for the most reliable results. Later planting can still work, but it usually depends more on variety maturity, warmer microclimates, and simple protection like row cover or low tunnels.
Common Timing Mistakes
These patterns show up again and again in Alberta — especially in typical years.
- Waiting too long after last frost to plant warm-season crops, which compresses harvest timing.
- Expecting late plantings to finish — cooling nights often slow crops earlier than expected.
- Assuming conditions are uniform across the region — frost timing often varies widely by elevation, exposure, and shelter.
- Relying on calendar dates instead of crop maturity and typical frost timing.
Frost Dates and Growing Conditions Across Alberta Cities
Growing conditions often vary more within Alberta than most gardeners expect. Differences in elevation, exposure, cold-air drainage, and nearby pavement or buildings can shift frost timing and change how much usable season you really have.
| City | Last spring frost | First fall frost | Frost-free days | Remaining GDD (May 15 → Aug 1, base 50) |
|---|---|---|---|---|
| Calgary | May 21 | Sep 18 | 120 | 907 → 324 |
| Edmonton | May 27 | Sep 10 | 106 | 896 → 284 |
| Red Deer | May 22 | Sep 12 | 113 | 833 → 286 |
| Lethbridge | May 21 | Sep 17 | 119 | 1332 → 540 |
| Medicine Hat | May 12 | Sep 25 | 136 | 1717 → 666 |
| Airdrie | May 21 | Sep 18 | 120 | 971 → 376 |
| Brooks | May 22 | Sep 21 | 122 | 1384 → 528 |
| Canmore | Jun 19 | Aug 23 | 65 | 503 → 197 |
| Cold Lake | May 19 | Sep 16 | 120 | 1020 → 323 |
| Fort McMurray | May 29 | Sep 07 | 101 | 832 → 263 |
| Grande Prairie | May 21 | Sep 10 | 112 | 897 → 305 |
| Lloydminster | May 18 | Sep 17 | 122 | 1027 → 354 |
| Spruce Grove | May 07 | Sep 25 | 141 | 916 → 290 |
| St. Albert | May 07 | Sep 25 | 141 | 916 → 290 |
| Wetaskiwin | May 20 | Sep 14 | 117 | 866 → 272 |
| Okotoks | May 21 | Sep 18 | 120 | 866 → 263 |
| Cochrane | May 21 | Sep 18 | 120 | 971 → 376 |
| Camrose | May 20 | Sep 14 | 117 | 937 → 313 |
| Lacombe | May 22 | Sep 12 | 113 | 833 → 286 |
| Leduc | May 27 | Sep 10 | 106 | 896 → 284 |
| Peace River | May 21 | Sep 13 | 115 | 795 → 238 |
| Whitecourt | May 20 | Sep 15 | 118 | 949 → 324 |
| Slave Lake | May 26 | Sep 16 | 113 | 843 → 279 |
| Hinton | Jun 04 | Sep 04 | 92 | 679 → 225 |
| Banff | Jun 19 | Aug 23 | 65 | 503 → 197 |
| Rocky Mountain House | Jun 13 | Aug 25 | 73 | 589 → 205 |
| High Level | May 30 | Sep 06 | 99 | 860 → 238 |
| Fort Vermilion | May 30 | Sep 06 | 99 | 860 → 238 |
| Edson | Jun 04 | Sep 04 | 92 | 679 → 225 |
- Frost timing varies widely across the region, especially between colder pockets and more sheltered sites.
- Earlier-frost and shorter-season locations usually need faster-maturing crops and tighter planting timing.
- Warmer locations usually retain more remaining heat through the season, giving longer-season crops and later plantings better odds of finishing.
- Urban areas, walls, and sheltered gardens usually stay warmer than open rural or wind-exposed sites.
- Cold air settles in low spots, so slightly elevated beds often avoid the earliest frosts.
- South- and west-facing areas usually warm sooner in spring and can stay productive later into fall.
How the Growing Season Works in Alberta
Alberta is mostly a timing-and-variety season. Reliable results usually come from planting on time, matching maturity to the frost window, and making good use of the remaining summer heat.
- Start on time: early establishment is often the biggest controllable factor for warm-season success.
- Match crops to the window: dependable harvests usually come from realistic maturity timing, not optimistic timing.
- Use late summer well: fast greens, roots, and compact crops are often the best fit for a second round.
Microclimate note: local conditions still matter here. Low spots, exposed sites, and higher elevations often cool faster than the regional median suggests.
Late-summer note: by early August, the remaining heat often tightens quickly. Late plantings tend to work best when they are fast, cold-tolerant, or protected.
Remaining Season Heat in Alberta (Base 50 GDD)
Growing Degree Days (Base 50°F) measure heat accumulation. “Remaining GDD” shows how much usable heat is typically still available from a given date onward in a normal season.
| Planting date | Base | Typical GDD still available |
|---|---|---|
| May 15 | 50 | 868 |
| June 1 | 50 | 833 |
| July 1 | 50 | 626 |
| August 1 | 50 | 291 |
Use these values to judge whether a crop or variety still has enough heat left after planting. This is especially helpful for later sowings, shorter-maturity choices, and deciding whether a second round is realistic.
How Gardeners Adapt
Experienced gardeners in Alberta usually adjust their timing and crop choices to match how the season actually behaves, not just the calendar.
- Planting warm-season crops promptly once frost risk fades.
- Using row cover or low tunnels to smooth out temperature swings early and late in the season.
- Succession planting fast crops to keep beds productive through summer.
- Shifting late plantings toward greens, roots, and other reliable short-season crops.
- Watching local conditions closely and adjusting timing year by year.
Alberta Garden Planning Chart
A practical “typical year” for planning. Use it as a baseline, then adjust for microclimates and variety maturity.
| Stage | What it usually means |
|---|---|
| Early season | Start cold-tolerant crops, prep beds, and pay more attention to soil warmth and night temperatures than to the calendar alone. |
| Main planting | Around May 21, the main planting push usually begins as frost risk fades. Warm-season crops generally perform best when they get established promptly. |
| Peak growth | This is when water, fertility, spacing, and pest pressure have the biggest effect on final yield. |
| Late-summer decisions | Late plantings are usually tight, so fast crops and protected spots become much more important. |
| Finish window | Plan to have frost-sensitive crops mostly wrapped up by September 17. Cooling nights often slow crops before the first real frost arrives. |
Typical season length: 119 frost-free days between the median spring and fall frost dates.