What Can I Grow in a Cold Frame in the Winter?

You probably know that a cold frame can help you extend the growing season into the winter, but do you know what plants will thrive in this environment? In this article, vegetable farmer Briana Yablonski covers what plants you can successfully grow in a winter cold frame.

Close-up of a garden with long rows of cold frames with various plants growing. The cold frame appears as a low-profile, box-like structure constructed with materials such as wood and metal. The frames are white and open.

Contents

If you’re looking to extend your growing season into the winter, a cold frame is a great tool to have on hand. It captures the sun’s energy, creating a warm environment and protecting plants from the harsh weather outdoors.

Sometimes, people think that you can grow warm-weather crops like basil. Unfortunately, that’s not the case in most areas. The best crops can tolerate a bit of cold, so hardy greens and roots are good options.

I will cover the factors that impact what you can grow in a winter cold frame so you can plant crops that work for you.

The Short Answer

Your hardiness zone and the size and location of the cold frame both impact the crops you can grow during winter. Generally, cold-hardy vegetables like spinach, tatsoi, carrots, beets, and lettuce will grow well. You shouldn’t grow frost-sensitive crops like tomatoes, cucumbers, and basil.

The Long Answer

I’ll explain the factors that impact what crops you can grow and then dive into some specific crops that will work in your area.

Consider Your Hardiness Zone

View of a wooden cold frame against the background of an old wooden shed in the garden. The wooden cold frame is characterized by a rectangular structure crafted from wood, with a hinged lid covered in transparent panels. Lettuce plants grow in rows in a cold frame. Rhubarb Blush growing next to a cold frame in the garden bed. Rhubarb Blush showcases large, vibrant green leaves with prominent red veins and stalks that transition from green to a rich, deep red hue.
Consider your USDA hardiness zone when choosing crops.

While a cold frame helps extend your growing season, it won’t turn a frigid New England garden into a tropical oasis. That means considering your USDA hardiness zone before deciding when to plant.

The lower your hardiness zone, the colder the minimum winter temperature. Since I live in zone 7b, I can expect a minimum winter temperature between 5–10°F. Remember, this is the lowest average temperature I can expect, so most nights remain warmer than this, and there may still be a few nights that get a bit lower!

If you live in zone 5b, temperatures will likely dip below -10°F at least once. And if you live in zone 9b, you may only experience below-freezing temperatures a handful of times.

This range of low temperatures explains why there isn’t a one-size-fits-all answer for what you can grow. Although cold frames increase air and soil temperature, they won’t cause drastic changes in outdoor environments. That means gardeners in warmer regions can grow a wider range of crops than gardeners in colder regions.

The Impact of Cold Frames

Close-up of a cold frame with growing young lettuce and green onion plants. The cold frame is a rectangular structure, made of wood, with a transparent lid that serves as a protective cover for plants. The lettuce comes in bright green and purple.
Cold frames trap sunlight to increase air and soil temperatures.

Cold frames work by trapping heat from the sun. If you think about how sealed cars become warm on sunny, cold days, you’ll understand how they function.

As heat is trapped during the day, the air and soil temperatures increase. But these temperatures drop once night arrives, and the air inside is typically only 5–10°F warmer than the outside temperature. That means if it’s 0°F outside, it will still be quite cold inside the frame!

The location also impacts its effect. Those in full sun will be warmer than those in partial shade. And since south-facing or west-facing brick walls trap heat, warmth increases when situated against one of these walls.

Covering your plants with a floating row cover can add an additional layer of cold protection, but it will only increase the air temperature by a few degrees. Covering the outside of the cold frame with blankets or towels will provide a similar effect.

Remember to Keep Planting Dates in Mind

Close-up of a wooden cold frame with growing young plants. The cold frame is a gardening structure made of wood, resembling a low-profile miniature greenhouse. It features a solid base and a transparent top, made of materials like glass or polycarbonate. The transparent lid allows sunlight to reach the plants while providing a protective barrier against adverse weather conditions.
To harvest winter crops in December through February, plant them in September or October.

When people ask me when I plant fall crops like cauliflower, kale, and carrots, they’re often shocked to hear I get these crops in the ground in early August. It may sound obvious, but you can’t plant crops in late September if you want to harvest them in the middle of October! The same logic applies to winter crops.

Just because plants will survive cold temperatures doesn’t mean they will grow rapidly during shorter days. Crops slow their growth as days grow shorter, and plant growth almost ceases when days dip below ten hours.

If you hope to harvest crops in December, January, and February, plant them in September or October. By the time your last ten-hour day arrives, the plants should be about 90% mature.

Crops for Extreme Cold

If you live in an area that regularly dips below 10°F, you’ll want to choose the most cold-tolerant crops. The following plants will survive supremely cold temperatures, but it’s always a good idea to cover them with a layer of row cover during cold nights.

Although these plants will survive cold, they happily grow in cold frames that reach 50°F or 60°F during the day. Just remember to vent your frame on warm, sunny days!

Tatsoi

Close-up of a Tatsoi plant in a garden bed. Tatsoi, a distinctive leafy green, presents a rosette-like cluster of small, spoon-shaped leaves with a glossy, dark green color. The leaves form a compact bunch and have a smooth texture.
Tatsoi features slender stems and dark green leaves.

An Asian green similar to bok choy, tatsoi has thin stems topped with dark green leaves. You can plant tatsoi for baby greens, but I find that growing individual heads allows for better airflow. Varieties like “Rosette Tatsoi” can survive extremely cold temperatures. 

Spinach

Close-up of a growing Spinach in a sunny garden. Spinach is a cool-season leafy green with tender, flat or slightly crinkled leaves that form a rosette-like arrangement. The leaves are deep green. Spinach leaves are broad and smooth.
Spinach not only endures cold weather but also turns sweeter with frost.

Spinach can not only survive cold temperatures, but it becomes sweeter once frost arrives. Although short winter days will slow the plant’s growth, you can continue to harvest spinach throughout the winter.

Pick off larger outer greens and keep smaller inner leaves to grow. While all spinach is cold-hardy, ‘Bloomsdale’ is an excellent choice for cold climates.

Claytonia

Close-up of Claytonia plants in flower in a garden. Claytonia, commonly known as miner's lettuce, small features, circular leaves arranged in rosettes with a distinctive, succulent texture. The leaves are bright green. Delicate white or pink flowers emerge on slender stems above the foliage.
Claytonia thrives in temperatures below 0°F when cultivated in a sheltered environment.

If one veggie wins the title of winter king, it’s claytonia. Also known as miner’s lettuce, this succulent green can withstand temperatures below 0°F if it’s grown in a protected structure like a cold frame.

Kale

Close-up of Kale plants in a sunny garden. Kale is a hardy leafy green with curly leaves that are deep green. Its sturdy central stalk supports the frilly foliage, creating a rosette-like shape.
Thaw frozen leaves before harvesting and watch for aphids, which thrive in protected winter structures.

Most types of kale will survive temperatures down to 15°F. This applies to both mature plants and baby kale. ‘Dwarf Blue Curled Kale’ is especially cold-hardy. Like with all greens, let frozen leaves thaw before harvesting. Keep an eye out for aphids since they often flourish in protected structures during the winter.

Parsnips

Close-up of freshly picked Parsnips in a bed in a sunny garden. Parsnips, characterized by their long, tapering roots, have a cream-colored, smooth exterior. The roots reach impressive lengths and feature a cylindrical shape with a slightly bulbous bottom. The foliage consists of bright green, deeply lobed leaves that emerge from the top of the root.
Parsnips thrive in cold weather, with roots remaining snug in the soil within a cold frame.

The nutty cousin of the carrot, the parsnip is a cold-weather warrior. While the roots won’t grow much throughout the winter, they’ll remain cozy in the soil. Since parsnips like ‘All American’ take about three months to mature, plant the seeds in August for a winter harvest.

Cabbage

Close-up of cabbage with water drops growing in the garden. Cabbage is characterized by its tightly packed, round head composed of crisp, leafy layers. The leaves are light green with white veins.
Cabbages are suitable for cold regions, but due to space concerns, outdoor planting is preferred.

While all cabbage varieties can survive a light frost, varieties like ‘January King’ can tolerate temperatures near 0°F! Cabbages like ‘Copenhagen Market’ and ‘Red Acre’ can easily survive temperatures down to 20°F.

That means these cabbages are a great choice for cold frames in frigid areas. However, since cabbages take up so much space, I like to plant them outside if I can get away with it. 

Crops for Moderate Cold

If you live in an area where winter temperatures often dip below freezing but rarely below 10°F, you can grow a wider variety of crops. Try out the following plants.

Bok Choy

Close-up of young Bok Choy growing in a raised bed. Bok Choy, also known as Chinese cabbage, presents a unique appearance with its dense clusters of crisp, white stalks and dark green, glossy leaves. The plant forms a compact, upright bunch with smooth, broad leaves at the top.
Bok choy is resilient to light frosts, with some types tolerating temperatures down to 15°F.

Most types of bok choy will survive a light frost, and some varieties will tolerate temperatures as low as 15°F. Outer leaves can become damaged by heavier frosts, but you can peel off the damaged leaves and enjoy the tender interior.

Lettuce

Close-up of lettuce growing in a raised bed in a sunny garden. Lettuce is a leafy green with a distinctive rosette-like arrangement of tender, broad leaves of light green color. The leaves have a wrinkled texture and wavy edges.
Head and baby lettuce, sheltered in a cold frame and covered with row covers, withstand temperatures below 15°F.

Both head lettuce and baby lettuce can survive below-freezing temperatures. When they’re tucked into a cold frame and under a few layers of row cover, they remain unscathed when the outdoor temperature drops below 15°F.

Of course, some types of lettuce tolerate cold better than others. ‘Rouge d’Hiver’ and ‘Ice Queen’ are two great options.

Cilantro

Close-up of young Cilantro plants with water drops in a garden bed. Cilantro displays delicate, fern-like foliage with finely cut, lacy leaves that grow in clusters. The leaves are bright green.
Cilantro flourishes in cool fall weather, enduring temperatures below 15°F when covered.

While you may think of cilantro as a summer crop due to its presence in salsa, this herb thrives in cool weather. It actually grows better in fall than summer, and it can survive temperatures below 15°F as long as it’s covered. Large outer leaves may die, but tender inner leaves will continue to grow after the cold spell.

Arugula

Close-up of a growing Arugula in a garden. Arugula, a leafy green, showcases a distinctive appearance with elongated, lobed leaves that form a rosette-like arrangement. The leaves have a deep green color.
Arugula retains spiciness despite milder cold weather, requiring careful spacing and dry soil to prevent fungal issues.

Also known as rocket, arugula is one of my favorite greens to grow in winter. The cold weather causes the green to lose some of its sharpness, but it still remains delightfully spicy.

Since arugula is prone to develop fungal diseases in moist conditions, I keep the soil relatively dry and space the plants about an inch apart. While ‘Astro’ arugula is often my go-to option for arugula, I turn to the wild and cold-hardy ‘Rocky’ arugula in the winter.

Radishes

Close-up of growing Radishes in a garden. Radishes feature crisp, round roots that come in red. The foliage consists of lush, green leaves that emerge from the top of the root.
A cold frame helps maintain soil warmth, preventing frequent freezing.

Radishes can survive below-freezing temperatures, but the roots will become pithy and undesirable if they frequently freeze and thaw. And trust me, biting into a soft radish doesn’t provide the same satisfaction as chomping into a crisp root.

Since a cold frame traps heat, the soil stays warm and prevents frequent freezing. If you’re expecting a cold, cloudy period, you can also protect your radishes with a few layers of row cover. Large radishes like ‘Mantanghong Watermelon’ are especially good choices.

Carrots

Close-up of freshly picked carrots in the garden on wet soil. Carrots are recognized by their slender, tapering roots that come in orange. The roots have a smooth exterior and a crisp, sweet taste. The foliage consists of feathery, fern-like green leaves that emerge from the top of the root.
Winter carrots are known for their superior sweetness due to concentrated sugars in cold temperatures.

In case you haven’t heard, winter carrots are the best you’ll find. That’s because cold temperatures cause the plants to concentrate sugars in their roots, leading to a pleasantly sweet taste.

Although some carrot greens may die when temperatures dip below 15°F, the roots will persist. Just make sure to harvest your carrots before the ground fully freezes.

Scallions

Close-up of growing Scallions in a garden. Scallions, also known as green onions or spring onions, present a slender and elongated appearance with crisp, hollow stems and vibrant green shoots. The slender stalks grow in clusters and feature a delicate, cylindrical structure. Some leaves are dry, yellowed, drooping.
Scallions maintain fresh pungency, with ‘Evergreen Hardy’ as a great cold-tolerant variety.

Also known as green onions, scallions are my favorite allium to grow in winter. The pungent whites and greens remain fresh throughout the winter.

While all types of scallions are frost-tolerant, ‘Evergreen Hardy’ is the most cold-tolerant variety I’ve found. I’ve grown it outdoors under row cover, and it has survived temperatures as low as 10°F.

Turnips

Close-up of a gardener's hands in beige dirty gloves harvesting Turnips in the garden. Turnips exhibit a distinctive appearance with their round roots, featuring smooth, white and purple skin and crisp, tender flesh. The roots have a contrasting color between the top and bottom portions, with the upper section being a mix of white and purple hues. The edible leaves, known as turnip greens, emerge from the top of the root, showing a vibrant green color and a slightly coarse texture.
Salad turnips thrive in winter cold frames, staying content as long as external temperatures stay above 15°F.

Both salad turnips, like ‘Market Express’ and cooking turnips, like ‘Purple Top White Globe,’ grow well in winter cold frames. As long as the outdoor temperature remains above 15°F, your turnips will remain happy tucked inside the shelter of the frame.

Some leaves may die during a cold spell, but the roots will remain unaffected. You should only worry about the roots if it remains below 20°F for a few days.

Parsley

Close-up of a growing parsley plant in the garden. Parsley is characterized by its lush, dark green, and deeply divided leaves, creating a dense and bushy growth habit. Growing in a rosette-like arrangement, parsley forms a low mound, and its delicate, fern-like foliage adds an elegant touch to gardens.
Flat-leaf and curly-leaf parsley, with protection, can thrive in conditions below 15°F.

Both flat-leaf and curly-leaf parsley can survive temperatures down to 20°F. When you add the protection of a cold frame (and a few layers of row cover), this herb can easily survive when outdoor temperatures drop below 15°F. The older outer leaves may die during periods below 10°F, but the new growth will survive and keep growing.

Crops for Warmer Areas

If you live where the temperature rarely drops below 25°F, you can successfully grow the following crops. Although these plants prefer above-freezing temperatures, they can withstand light frosts, especially if protected by a cold frame.

Beets

Close-up of growing Beets in a sunny vegetable garden. Beets showcase a distinctive appearance with their bulbous, vibrant roots that are deep red. The smooth, round roots are topped with edible, deeply lobed leaves, known as beet greens, that emerge from the root.
Some beet varieties thrive in winter, enduring temperatures in the mid to upper 20s.

Red, golden, and Chioggia beets are all excellent candidates. They can easily survive temperatures in the mid to upper 20s, but they will require a layer or two of frost cloth if you want the roots and greens to survive below 20°F. Remember that vegetables won’t grow much during short winter days, so aim for mature beets by Thanksgiving.

Swiss Chard

Close-up of Swiss chard plants growing in rows on a raised bed in a sunny garden. Swiss chard boasts large, vibrant, and glossy leaves of bright green color. The sturdy stems, known as ribs, are bright red and yellow.
Swiss chard, less cold-resistant than spinach and kale, survives below-freezing temps but benefits from a row cover during hard freezes.

The cold-hardiness of Swiss chard varies depending on the variety, but most types of Swiss chard tolerate less cold than greens like spinach and kale. These greens will survive below-freezing temperatures, but they’ll appreciate a blanket of row cover if hard freezes are in the forecast.

Fennel

Close-up of growing Fennels in a garden. Fennel is distinguished by its feathery and delicate foliage that resembles dill. The plant features tall, upright stems that bear finely dissected leaves, creating a lacy and fern-like appearance. The base of the fennel plant forms a bulbous, crisp, and slightly flattened structure with overlapping layers.
Fennel, prized for its sweet anise flavor, is a winter cold frame must-have, enduring temperatures down to 25°F.

I love the sweet anise flavor of fennel, so it’s a must-have in the winter. Fennel can survive temperatures down to 25°F, but not much colder than that.

Another thing to keep in mind is fennel’s height. The feathery leaves can easily reach three feet tall, so make sure your cold frame is tall enough to accommodate them.

Napa Cabbage

Close-up of freshly picked Napa cabbages. Napa cabbage displays a distinctive appearance characterized by its elongated shape and tightly packed, crinkled leaves forming a dense head. The leaves have a pale green color and a crisp, tender texture.
Napa cabbage, less cold-tolerant than green and red cabbage, thrives in areas with temperatures above 20°F.

Napa cabbage is less cold-tolerant than green and red cabbage, so it’s better suited for areas where winter temperatures remain above 20°F. If your Napa becomes damaged by a freeze, peel off the damaged outer leaves until you find the undamaged heart.

Final Thoughts

With a cold frame and the knowledge to go with it, you’re ready to grow well into the winter! Remember that your hardiness zone impacts what winter crops you can grow, but even the coldest areas can grow through winter with the help of this method.

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