When to Sow Turnips in Vermont

Sow turnips in Vermont twice: in spring around the April 30 to May 10 last-frost span, and in late summer, counted back from the October 3 to October 13 first-frost span. Rutabaga skips spring and goes in during early to mid July. Those dates come from Burlington, the mildest corner of the state, so the hills and the Northeast Kingdom shift earlier in fall. Here is how to read them.

The short answer for Vermont

Sow turnips from the last-frost window forward in spring, and again in the second half of summer for a fall crop. The fall sowing is the one most gardeners get wrong.

The frost dates need a careful reading. NOAA’s 1991-2020 Climate Normals for the Burlington station give a last spring frost of April 30 to May 10 and a first fall frost of October 3 to October 13. Both are 32°F freeze probabilities, and the range is the 30-70% band. Neither date is a promise. Between April 30 and May 10, the odds of another 32°F freeze sit somewhere between 30 and 70 percent. The same logic applies in fall. A freeze can show up before October 3 in a cold year, and a mild year can run past October 13.

Turnips tolerate light frost, so the spring window opens a bit ahead of the last-frost span, as soon as the soil is workable and not sodden. The fall window is a countdown. Check the days to maturity on the seed packet and count backward from the first-frost span. The table below does that arithmetic for two example crops. The 50-day and 90-day figures are illustrations, so swap in the number printed on your own packet.

These are the latest dates, with no cushion. Turnips and rutabaga keep sweetening after a light frost, so a hard freeze is not the deadline for them that it is for beans or tomatoes. Still, a root that is half-sized when the ground locks up is a wasted bed. Sow a week or two ahead of the latest date and you give the crop room to bulk up. For choosing what to sow, see The Best Turnips and Rutabaga for Vermont. The full growing picture lives in Growing Turnips and Rutabaga in Vermont.

What will not work here

A 90-day rutabaga sown in late July. That one fails on arithmetic alone. Count 90 days from July 25 and you land around October 23, past even the late end of the first-frost span. The roots will form, but small, and you will be harvesting into a freezing garden.

Spring-sown rutabaga is a weaker bet than a July sowing, for a related reason. A crop that needs most of a season to size up has to run through the whole summer when it goes in during May. The fall sowing lets it mature in cooling weather instead. This page has no summer temperature or humidity figures for Vermont, so it will not claim exactly how hot July gets. The seasonal logic still points the same way: slow roots belong in the back half of the year.

Treating the Burlington frost dates as the rule for the whole state is the next mistake. The source flags it directly: Burlington sits on Lake Champlain, the mildest corner of the state, and the Green Mountains and the Northeast Kingdom run substantially shorter. A gardener on a ridge who counts back from October 3 is counting from a date that may arrive earlier at that elevation. The cure is to sow earlier, not to hope.

Leaving roots in the ground as a winter crop will not work either. The mean daily minimum of the coldest month in Burlington is 12.9°F. That is an average of the night lows, so the coldest nights run well below it. Turnips and rutabaga are harvested, not overwintered, and roots left unprotected into that kind of cold turn to mush and are not worth digging in spring.

Last, a single early sowing does not cover you. Turnips left in the ground after maturity get woody and pithy, so one big sowing in August means everything ripens at once. Two or three small sowings a couple of weeks apart spread the harvest and hedge against a bad stretch of weather.

What changes across Vermont

There is no single Vermont answer. The USDA Plant Hardiness Zone Map (2023, built on 1991-2020 normals) puts the state at 3b to 5b. USDA zones are built on one variable, the average annual extreme minimum temperature, and each half-zone step is 5°F. Running from 3b to 5b, then, means a spread of about 20°F in winter extremes inside one small state.

Hardiness zones describe how cold the worst night gets, not how many growing days you have, so they are only a rough proxy for sowing dates. Still, the pattern holds: the colder end of that range is where the season is shortest. Burlington’s dates are the best this page has, and the facts specifically warn that the Green Mountains and the Northeast Kingdom run substantially shorter. This page has no frost dates for those areas, and it will not invent them.

What to shift if you garden north or high

Move the fall sowing earlier, and let the packet’s days to maturity decide how much earlier. Choose the faster turnips over the slow ones, and treat rutabaga as a crop you commit to in early July at the latest, not mid-July. In spring, wait for the soil instead of the calendar, since cold ground sits wet longer at elevation. A gardener in a valley pocket may be a half-zone warmer or colder than the town next door.

Which zone you are in is not something this page can tell you. Look up your location on the USDA Plant Hardiness Zone Map and note the half-zone, then compare it to Burlington’s published frost span as a way to judge how far to shift.

Where to check this for your own county

Start with University of Vermont Extension, the state’s land-grant extension service. It is the place to find what actually gets recommended where you live.

Look for two things. The first is a local planting calendar, ideally one broken out by region or county rather than a statewide table. The second is any record of varieties trialled in your county, since a turnip that performs in the Champlain Valley may not suit a cold hollow in the Northeast Kingdom. If the extension office publishes a vegetable planting guide with frost-date ranges, compare its dates to the Burlington span above and see which direction they lean.

A county recommendation beats a state one, and this page is the state one. It rests on one station’s data, adds the caution that most of Vermont is colder than that station, and cannot see your slope, your soil, or your cold-air pockets. The page also has no extension turnip calendar for Vermont to cite, so it does not claim one. Where extension staff or local gardeners give a different date from the ones here, trust them. They are working from your ground.

Checking this against your own garden

Your own observations outrank every date above. Three are worth watching.

• Soil warmth by feel. A handful of spring soil that crumbles instead of clumping, and does not feel icy when you hold it, is ready for turnip seed. If it stays cold and wet long after the Burlington dates, your spot runs later than the lake.
• The first flush of male flowers. The first male blooms on squash or cucumbers mark when your summer is really running. If they arrive late compared with neighbors, your season runs behind and your fall sowing dates should move earlier.
• The first true leaves. The seed leaves come first, and the true leaves, which look like small turnip leaves, follow. If they show up slowly after sowing, the stand is behind, which matters most for a late-summer sowing counting down to frost.

Write the dates down each year. Three seasons of notes on when the soil crumbled, when the first male flowers opened, and when the first frost blackened your tender plants will tell you more about your own microclimate than any statewide span can.

Some gardeners also time this by the Moon: when to plant turnips by the moon, as almanac tradition rather than fact.

Common questions

Can I sow turnips in spring in Vermont?

Yes. Turnips tolerate light frost, so sow as soon as the soil is workable, around the April 30 to May 10 last-frost span or a little earlier. Spring turnips need to size up before summer gets going.

When should I sow rutabaga?

Sow it for fall, in early to mid July if you are near Burlington, using a 90-day variety as the example. Colder and higher gardens should go earlier. Check the days to maturity on your packet and count back from the first-frost span of October 3 to October 13.

Is it too late to sow turnips in September?

Usually, for full-sized roots. A 50-day example turnip needs a sowing between August 14 and August 24 to finish by the October 3 to October 13 span. A September sowing may still give you young, small roots and greens.

Do turnips overwinter in Vermont?

Not reliably. The mean daily minimum of the coldest month in Burlington is 12.9°F, and colder zones are colder still. Harvest in fall instead of leaving roots in the ground.