Last Updated on October 23, 2026

Vegetables You Can Leave in the Ground Over Winter

Carrots, parsnips, leeks, kale, spinach, garlic and onions are the overwintering vegetables to count on: plant or grow them to size in fall, leave them in the bed, and harvest through winter or in spring. Roots and leeks hold under a thick layer of straw or leaves. Garlic and overwintering onions go in during fall and sit under mulch until spring. Kale and spinach come through best under row cover, a low tunnel or a cold frame, because mulch piled on leaves blocks their light. Pull the roots and leeks before they start growing again in spring, or they turn woody and bolt.

This page is about what survives the whole winter. For what to cover on a single cold night, use my vegetable frost tolerance chart and how to protect plants from frost; neither one has separate single-night numbers for leeks or parsnips, which this page covers for overwintering.

Overwintering vegetables chart

The temperature column comes from Table 1 of Oregon State University Extension’s winter vegetable guide, written for small farms and gardens in the mild, wet winters west of the Cascades. Oregon State says its hardiness numbers were collected from seed companies, experienced farmers and its own observations, for guidance only, not a promise.

Where winters run colder than those numbers, protection does the rest. University of Maryland Extension says row cover adds 2 to 8°F of frost protection, and it calls the medium and heavyweight grades useful for overwintering crops.

By how forgiving they are without protection: garlic, onions and leeks are the safest bets under mulch alone; kale and spinach need a cover that lets light through; carrots and parsnips need mulch and are more weather-dependent; lettuce, covered further down, is the biggest gamble of the bunch.

Leave carrots and parsnips in the ground, step by step

1. Have them full size by fall. UNH Extension’s Becky Sideman, who researches season extension, says carrots meant to overwinter (she keeps hers in a high tunnel) should be big by the time fall comes and they stop growing. University of Maryland Extension says vegetable growth is very limited once the sun is up less than 10 hours a day, so plan on roots holding through winter, not growing.
2. Let the cold sweeten them first. Iowa State University Extension says the longer parsnips stay in the ground in fall, the sweeter they will be.
3. Mulch after the hard freezes. Iowa State’s parsnip harvest guide says to cover the bed with several inches of straw after several hard freezes. My guide to growing big carrots says that in cooler climates you can leave carrots in the soil all winter and harvest them fresh in spring by covering the soil with a substantial layer of mulch.
4. Keep the snow off. University of Illinois Extension uses mulch, row cover or a low tunnel to keep snow off the carrots for easier harvest, and digs winter carrots when it is above freezing.
5. Dig before spring growth. Utah State University Extension says parsnips lose flavor and turn woody if you do not harvest them before new leaves begin to grow. Carrots go the same way: Sideman says that once they send out fine feeder roots in spring they turn tough, woody and bitter, so pull them as soon as you see that.

Two warnings. Sideman says carrots are more cold-sensitive than parsnips, and she would not expect high odds of success with carrots outdoors in a given year without some extra protection. And Oregon State notes that carrots can be damaged by soil-dwelling pests and diseases, often surviving better in storage without tops than in the ground, especially where the bed stays wet. If your bed stays soggy, dig the roots and use my vegetable storage chart instead.

Kale, spinach and other greens: cover, do not bury

Greens overwinter differently from roots. In a UNH Extension podcast, Sideman calls straw and mulch fabulous insulators, but says straw also blocks light. For leafy crops, use a cover that lets light through.

• Row cover. Maryland says kale, spinach, arugula, corn salad, parsley and chicories overwinter with protection and resume growth in spring. It adds that the cover can be moved aside on mild winter days to give the plants more light and air.
• A low tunnel with plastic. Sideman says plastic holds more heat than fabric row cover, though it will not carry plants through every cold snap. Her picks for overwintering in low tunnels are kale, spinach, onions and scallions, crops that do not usually survive her unprotected winters but come through fine under a tunnel.
• A cold frame. My cold frame tips cover the basics: at least six hours of sun, opening the lid on warm days, and insulating it at night with bubble wrap, row cover or old blankets.

Give greens some size before winter. Sideman’s research found spinach planted earlier and picked through fall gave the most, resting through winter and harvested again in spring.

I built a high tunnel over my raised beds to grow cool-weather crops through late winter and early spring. On a sunny day it overheats fast, so it needs venting.

Garlic, onions and leeks

Garlic is planted for winter. My guide to planting garlic in raised beds puts the cloves in at or after your first fall frost and mulches heavily. University of Minnesota Extension covers garlic beds with 3 to 4 inches of leaf or straw mulch to even out winter temperatures, and pulls it back in spring once the threat of hard freezes is over so the soil can warm. I like leaf mulch, which I pick up with my mower. I spray the leaves down and lay a few dead branches over them so they stay put. Straw blows around less, but it is not free like leaves.

Onions overwinter only as overwintering varieties planted small. Oregon State says fall-planted onions should go into winter about a quarter inch across, pencil size, because larger plants are pushed to bolt before the bulbs form. Utah State says mulch is used on overwintered onions to cut winter damage.

Leeks keep growing slowly through the cool season instead of going dormant, Oregon State says, and any not harvested by spring will bolt. University of Maryland Extension separates summer leeks from overwintering leeks, which are harvested the spring after planting. For winter digging, it says to hill soil around the plants and cover them with a heavy layer of mulch. A summer type will not take that: the Alto seed on my leek spacing page is a summer leek, not winter-hardy, so harvest it before hard cold. Sources do not agree on how cold leeks take: University of Minnesota Extension calls leeks fairly frost tolerant and says temperatures as low as 20°F may not harm some varieties, well above the 5°F in the chart. Treat 5°F as the hardiest-variety floor, not a guarantee, and lean toward the heavier end of the mulch range for leeks.

What not to leave out over winter

• Tender crops. Tomatoes, peppers, beans and squash do not tolerate freezing. The frost tolerance chart has the harvest-first line for each.
• Brussels sprouts. Sideman does not see much potential in overwintering them: once it gets into the teens they cannot recover and they decay. Grow them into fall and pick them.
• Lettuce. Sideman says brassicas are better overwintering candidates than lettuce. In her research, lettuce in low tunnels lasted well into winter some years and died much earlier in others.

Once frost has killed the summer crops, the rest of the bed work is in my steps to prepare your garden for winter, and the fall sowing side is in my fall crop planting guide.

Video: 8 crops to plant this fall for a spring harvest

Garlic and onions are not the only crops that go in during fall and come up in spring. In this video I cover eight of them, including garlic, shallots, onions, cold-hardy greens and a bean that handles cold, plus how to tuck them in for winter.

Quick questions

Can you leave carrots in the ground over winter?

Yes, under a heavy mulch. My guide to growing big carrots says that in cooler climates you can leave them in the soil all winter and harvest them fresh in spring by covering the soil with a substantial layer of mulch. UNH Extension’s Becky Sideman says to dig them before they start growing again in spring, when they turn tough and woody.

Can kale survive winter outside?

Often, with help. Oregon State University Extension lists kale as hardy to about 0°F in its mild-winter guide. UNH Extension’s Becky Sideman says kale, spinach, onions and scallions do not usually survive her unprotected winters but come through fine under a low tunnel.

When should I mulch vegetables for winter?

For parsnips, after several hard freezes: that is when Iowa State University Extension covers them with several inches of straw. Garlic gets 3 to 4 inches of leaf or straw mulch right after planting, and University of Minnesota Extension pulls it back in spring once hard freezes are over.

What vegetables should not be left in the ground over winter?

Tender crops like tomatoes, peppers, beans and squash, which do not tolerate freezing. UNH Extension’s Becky Sideman also sees little potential in overwintering Brussels sprouts, which cannot recover once it gets into the teens, and calls lettuce riskier than the brassicas.

Plan a fall planting that overwinters

Overwintering starts with knowing when cold arrives. Enter your zip code on Plan My Garden and it finds your frost dates, including your first fall frost. Plan My Garden is free to start: enter your zip code, draw your beds, pick garlic, carrots, kale and everything else you want to grow, and it places each plant at square-foot spacing and builds a planting schedule (start indoors, transplant and direct sow dates) from your frost dates.

Related: Vegetable Frost Tolerance Chart · How to Protect Plants from Frost · 5 Tips for Using a Cold Frame