Sow turnips in Yukon starting around June 5, the average last spring frost at Whitehorse, and finish by roughly the end of June. That date is a midpoint, not a guarantee: in half of all years the last frost comes later. Rutabaga is the tighter call, because the average gap between the last spring frost and the first fall frost is only about 81 days.
The short answer for Yukon
Environment and Climate Change Canada puts the average last spring frost at the Whitehorse A station on June 5, and the average first fall frost on August 25. Both come from the 1981-2010 Canadian Climate Normals. Turnip seed goes in from about June 5, and the last sowing meant to make a root crop falls in late June.
What those dates measure matters. They are mean dates, so each one marks the point where frost arrives earlier in half the years and later in the other half. June 5 is not the day the danger ends. In one year out of two, a frost still lands after it. The same logic applies to August 25: in some years the first killing frost arrives before it, and the season you planned for shrinks.
The late-June cutoff comes from simple arithmetic. Seed packets for turnips commonly list somewhere around 40 to 60 days to harvest. Count 60 days back from August 25 and you land in the last days of June. Turnips tolerate a light frost, which gives you a little slack in both directions, but not much. In practice the window is about three weeks wide, opening on the average last-frost date and closing before July.
One caveat travels with every number here. The figures come from a single station, Whitehorse A, and the territory is not one climate. Northern and upland districts run weeks behind it, so treat the dates as the center of a window for a Whitehorse-type site, then adjust. The normals also cover 1981-2010, while the US figures elsewhere on this site cover 1991-2020, so don’t set them side by side without allowing for that.
Choosing which turnip to sow is a separate decision. Our guide to The Best Turnips and Rutabaga for Yukon sorts types by speed to maturity, and the broader page on Growing Turnips and Rutabaga in Yukon covers the crop from seed to storage.
What will not work here
Slow rutabaga is the first casualty. Many rutabaga varieties are sold at 90 days or more from seed. The average frost-free stretch at Whitehorse A is about 81 days. Even if you sowed on the very first day of the window, the arithmetic is against you, and in the half of years when frost lingers past June 5 it is worse. Rutabaga is not impossible, but it is a gamble, and only the quickest types belong in it.
Treating June 5 as a safe date is the second mistake. Because it is a mean, it describes a coin flip. Seedlings that emerge under a hard late frost can be set back or lost, and gardeners who sow everything the same afternoon have nothing in reserve. Staggering two or three small sowings across the window is a better hedge than one big row.
The “second crop” borrowed from milder places fails too. In the southern states, a late-summer sowing of turnips for fall harvest is routine. Here, a sowing in late July has only about a month before the August 25 average first frost. That might give you tender greens, but it will not give you a sized-up root. The fall turnip belongs to a different climate than this one.
Cold itself is the third thing to respect. The mean daily minimum of the coldest month at Whitehorse is -19.2 °C, which is a deep, long winter, and soil that thaws slowly. Seed sown into cold ground sits and waits, or germinates unevenly. A cold snap after the plants are up can also push turnips to bolt, and Yukon’s very long June days can add to that pressure. Bolted plants send up a flower stalk and leave you with a tough, woody root.
Last, a lot of popular turnip advice is written for heat: shade cloth, deep mulch to cool the roots, summer irrigation schedules. This is a cold-limited territory, not a heat-limited one. Heat tactics solve a problem you will rarely have, while the real constraint is the number of growing days. Spend your effort on warming soil early and choosing fast varieties instead.
What changes across Yukon
The hardiness figure for the reference city, Whitehorse, is zone 1b in the Canadian system, from Natural Resources Canada’s 1991-2020 normals. It is not a USDA zone and does not convert to one. NRCan says plainly that there are no simple conversions between the two systems: the Canadian method draws on seven climate variables, the USDA on one, and Canadian zone 4a alone overlaps nine USDA zones, from 3a to 7a.
That number describes one city, not the whole territory. Yukon covers a huge area of valleys, plateaus and mountains, and there is no single answer for it. The frost dates on this page share the same limit. A garden well north of Whitehorse or high on a slope will warm later in spring and freeze earlier in fall, by weeks rather than days.
If that sounds like your site, shift the whole calendar. Open your sowing window later, close it earlier, and lean harder on the fastest turnips, leaving rutabaga to the experienced and the stubborn. Row cover and a south-facing spot buy a few days at each end. A sheltered river valley may match the Whitehorse figures closely or even beat them, so the direction of the shift depends on where you garden.
To find your own zone, use Natural Resources Canada’s Canada’s Plant Hardiness Site, which lets you look up a community directly. This page will not tell you which zone you are in, because it cannot see your slope, your shelter, or your elevation. Treat the map as your starting point and your own garden as the final word.
Where to check this for your own county
Yukon has no counties, so the working unit is your community or district. The principle holds anyway: a local recommendation beats a territorial one, and this page is the territorial one. It rests on one station’s averages and cannot know what your valley does.
Start with Agriculture and Agri-Food Canada, the federal department. The territorial agriculture office would be the more specific source, but its site refuses automated checks, so we link the federal one because we could confirm that it works. This page does not have a Yukon-specific turnip calendar from an extension-type service, and it will not borrow one from another province or state.
Once you are there, look for two things:
- A planting calendar for your area, ideally one that names turnips or other cool-season root crops and gives dates for your community rather than the territory as a whole.
- Variety trial results from nearby: which turnips and rutabaga were grown, how many days they took, and how they handled the local season.
If a local source gives a date that differs from the June 5 on this page, believe the local one. It reflects your own frost pattern, and it was probably set by people who have watched real harvests.
Checking this against your own garden
Every date above is an average, and your garden is a single year. Three observations will outrank the calendar.
- Soil warmth by feel. Dig a few inches down in the morning and grab a handful. If it is still cold enough to make your fingers ache, wait, however late it feels. Soil that crumbles instead of clumping and feels merely cool is ready. Beds that reach this stage first, usually the sunniest and best drained, are your warm microclimate.
- Native willows and birch near your garden. When willow catkins have opened (the male flowers appear first) and birch leaves are coming, the neighborhood has crossed a warmth threshold. Note the date each year. Within a few seasons you will have a local clock that beats a station 100 miles away.
- The first true leaves. The first pair that emerge after the seed leaves are the real test. If seedlings reach that stage in about two weeks, your soil is warm enough. If they stall, you sowed too early or the bed is cold, and the next sowing belongs somewhere sunnier.
Write the dates in a notebook. After two or three seasons, your own record will tell you more than the Whitehorse averages can.
If you follow the almanac, here is when to plant turnips by the moon. It is a tradition, not a proven method.
Common questions
Can I sow turnips before June 5?
Possibly, since turnips tolerate light frost, but that is a gamble. The date is the average, so frost comes later in half of years. If you try an early sowing, keep seed in reserve and sow a second small row a week or two afterward.
What is the last date to sow turnips for a root crop?
Late June, based on counting back roughly 60 days from the August 25 average first fall frost. A sowing in July may give greens, but not a reliable root. Northern and upland gardens should aim earlier in the window.
Is rutabaga realistic in Yukon?
Only with the fastest varieties and an early, warm start. Many rutabagas take 90 days or more, and the average gap between frosts at Whitehorse A is about 81 days. Turnips are the safer first crop, and rutabaga is a trial plot at best.
Do I need to protect turnips from the winter cold?
Not in the field, because turnips are grown as an annual here and harvested before the freeze. The coldest-month mean minimum of -19.2 °C matters for storage and soil thaw instead. Lift roots before hard frost and keep them cool but above freezing.