Saskatchewan sits at 52.17 degrees north, using Saskatoon as the reference point, and the longest day of summer there stretches to 16 hours and 31 minutes of daylight. That number, not the temperature, is what tells an onion when to stop making leaves and start making a bulb. Only the long-day group is built to use that much light. Six varieties documented on this site have a published range that reaches this latitude: Ailsa Craig, Barolo, Blush, Patterson, Redwing, and Walla Walla Sweet.
The short answer for Saskatchewan
Onions come in three day-length groups, and the trigger for each is fixed by genetics, not by how warm the soil gets. Short-day varieties start forming a bulb once the day reaches about 12 hours, according to Clemson Cooperative Extension’s home garden guidance on onions. Intermediate-day types wait for something in the 12-to-14-hour range. Long-day varieties hold off until the day stretches to somewhere between 14 and 16 hours. At 16 hours 31 minutes on the solstice, Saskatoon has more daylight to offer than any of those thresholds requires, which is exactly why the long-day group is the only one that makes sense there.
Six varieties on this site carry a published range wide enough to include 52.17°N:
- Ailsa Craig (long-day, 38-60°N)
- Barolo (long-day, 38-55°N)
- Blush (long-day, 38-55°N)
- Patterson (long-day, 38-55°N)
- Redwing (long-day, 43-65°N)
- Walla Walla Sweet (long-day, 35-55°N)
Redwing stands out for a reason worth noting: its range runs all the way to 65°N, well past Saskatoon and into territory that gets even more summer daylight. That makes it the safer pick for anyone gardening near the northern edge of the province, where the season shortens fast even as the days grow longer. The other five all cover 52.17°N comfortably without needing the extra headroom Redwing offers, which makes them solid choices for most of the province’s settled, southern band where Saskatoon itself sits.
What will not work here
This is the part that actually saves a gardener a wasted season. Twenty-five varieties documented on this site are published for latitudes that stop short of 52.17°N, and planting any of them in Saskatchewan does not produce a smaller version of what the catalog promises. A short-day or intermediate-day onion hits its bulbing trigger in early summer, while the plant is still a handful of thin leaves, and it forms a bulb the size of a marble and simply stops. It will not catch up no matter how much longer it stays in the ground, because the day-length signal that starts bulbing does not care how big the plant is yet. A handful of long-day varieties on this list have the opposite problem: their published range tops out at 45 or 50°N, south of Saskatoon, which suggests the short northern season doesn’t give them enough frost-free days to size up before their own trigger fires. Either way, the result is an undersized bulb that doesn’t cure properly and rots in storage instead of keeping through winter.
- Bridger (long-day, 35-50°N), range tops out at 50°N, short of Saskatoon’s 52.17°N.
- Cabernet (intermediate-day, 35-45°N), bulbs before the plant sizes up this far north.
- Calibra (intermediate-day, 35-45°N), same intermediate-day trigger problem.
- Candy (intermediate-day, 33-40°N), range ends well south of the province.
- Elsye (intermediate-day, 32-45°N), bulbs too early for a Saskatchewan season.
- Expression (intermediate-day, 32-45°N), same limitation.
- Frontier (long-day, 40-50°N), rated no farther north than 50°N.
- Gabriella (short-day, 20-35°N, no page of its own on this site), bulbs almost as soon as it’s planted.
- Madalyn (short-day, 20-35°N, no page of its own on this site), same short-day problem.
- Monastrell (intermediate-day, 35-46°N), range ends at 46°N.
- New York Early (long-day, 38-50°N), tops out at 50°N.
- Powell (long-day, 43-47°N), narrow range that ends at 47°N.
- Red Carpet (long-day, 40-45°N), range ends at 45°N.
- Red Long of Florence (intermediate-day, 38-50°N), bulbs too early this far north.
- Red Long of Tropea (intermediate-day, 35-48°N), same intermediate-day issue.
- Red Rock (short-day, 30-36°N, no page of its own on this site), short-day, bulbs undersized.
- Red Sensation (short-day, 25-35°N), short-day trigger far too low for Saskatoon’s daylight.
- Rossa di Milano (long-day, 38-50°N), long-day but rated no farther than 50°N.
- Safrane (long-day, 42-50°N), tops out at 50°N.
- Scout (intermediate-day, 32-46°N), bulbs before the plant is ready.
- Sierra Blanca (intermediate-day, 32-45°N), same problem.
- Talon (long-day, 42-50°N), rated no farther north than 50°N.
- Texas Grano 1015Y (short-day, 25-35°N), a classic short-day sweet onion, wrong latitude entirely.
- Vidora (short-day, 25-35°N), short-day, bulbs tiny and early.
- White Castle (short-day, 30-38°N, no page of its own on this site), short-day mismatch.
What changes across Saskatchewan
Saskatchewan is not a single point on the map, and it’s worth remembering that the figures above belong to one city. The province runs from roughly the 49th parallel at the U.S. border up to near the 60th parallel where it meets the Northwest Territories, a span of more than ten degrees of latitude. Saskatoon, at 52.17°N, sits closer to the southern half of that range, which is also where most of the province’s population and farmland are concentrated. A gardener near the U.S. border gets a shorter longest day than Saskatoon’s measured 16 hours 31 minutes, though still well within long-day territory. A gardener near the northern edge gets noticeably more summer daylight than Saskatoon does, which pushes the advantage even further toward long-day varieties with wide northern range, like Redwing.
| Location | Approx. latitude | Summer day length vs. Saskatoon | What it changes |
|---|---|---|---|
| Near the U.S. border (south) | ~49°N | Shorter than Saskatoon’s measured 16h31 | Still solidly long-day territory; margin for the six listed varieties is slightly wider |
| Saskatoon (reference city) | 52.17°N | 16h31 (measured) | The figures used throughout this page |
| Near the Northwest Territories border (north) | ~60°N | Longer than Saskatoon’s 16h31 | Varieties rated to the upper range, like Redwing at 43-65°N, become the safer pick as the growing season itself gets shorter |
The practical upshot: a reader gardening close to Saskatoon can follow this page’s list directly. A reader near either edge of the province is dealing with a meaningfully different day length and, in the north, a shorter frost-free window to work with. That second factor, season length rather than day length, is often the bigger constraint the farther north you go.
Checking this against your own garden
None of the figures above replace a look at your own conditions, especially if you’re gardening well north or south of Saskatoon. A few things are worth confirming before you settle on seed or sets for spring.
- Look up your own latitude if you’re gardening more than a degree or two from Saskatoon, north or south, a simple online latitude lookup for your town is enough.
- Check your average last spring frost date and first fall frost date, since those set the actual planting and harvest window regardless of day length.
- Contact your nearest Saskatchewan Agriculture regional office or provincial extension service for locally trialed varieties and current planting-date guidance.
- Compare your longest summer day to Saskatoon’s 16h31 if you’re near the province’s northern or southern edge, since that shifts how much margin you have with intermediate-versus-long-day choices.
- Ask about your soil’s drainage and texture locally, since bulbing onions still need loose, well-drained ground no matter how well the variety matches your latitude.