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How to plant a winter vegetable garden with crops to harvest throughout the cold season. Includes tips on when to sow and plant winter crops, growing both outdoors and undercover, and overwintering your vegetables for spring.
People often think that gardening stops in winter but that doesn’t have to be the case. As day lengths shorten, plant growth slows and the soil cools, but many crops can tough it out. That means that you can pick and dig many vegetables throughout the cold months. Just think, if you plan and plant a winter vegetable garden now, you’ll ensure that you have homegrown food ready to eat all year long. While other growers have bare and empty gardens in winter, yours could be filled with a bounty!
The reason why some crops survive winter is they need a period of prolonged cold, known as vernalization, in order to flower and set seed in spring. These biennial vegetables include carrots, chard, beets, and onions. This period of cold also develops their flavor, for example, parsnips can taste sweeter after a frost, as the cold turns their starch to sugar.
There’s another good reason to keep your garden filled with crops in winter — they’ll help reduce soil erosion and you’ll lessen the chance of nitrates leaching away from bare soil. That means that by planning ahead you can fill your vegetable garden with food right through to early spring and benefit your soil’s health.
List of Winter Vegetables to Grow
How we plant a winter vegetable garden will depend on our specific zone. Winter temperatures and conditions have a huge influence on what we can grow. How we grow and protect our crops matters too, so even if your winters regularly dip below freezing there are methods you can use to ensure you can grow food all year long.
Keep in mind that 25°F (-2.2°C) is a danger zone temperature for crops left growing outdoors without protection. Even a night that cold can kill off many root vegetables so be mindful of the weather and dig up crops if temperatures take a dive. Some vegetables are incredibly tolerant though, and leeks and parsnips will tolerant a staggering 0°F (-18°C). Here’s a list of winter vegetables and the coldest temperature they can withstand. As you can see, winter veg is incredibly hardy!
- Leeks and parsnips: 0°F (-18°C)
- Turnips, swede and kale: 10°F (-12°C)
- Garlic: 12°F (0-11°C)
- Broad beans: 14°F (-10°C)
- Chard, perpetual spinach, and radish: 20°F (-6°C)
- Cabbage and brussels sprouts: 20°F (-6°C)
- Carrots: 20°F (-6°C)
- Onions and shallots: 20°F (-6°C)
- Asparagus: 24°F (-4°C)
- Broccoli and winter cauliflower: 25°F (-3°C)
- Peas and Christmas potatoes: 28 °F (-2°C)
- Beetroot, kohlrabi and celeriac: 30°F (-1°C)
- Winter squash: 31°F (-0.5°C)
Growing a Winter Vegetable Garden
So what does a winter vegetable garden look like? It will be different based on where you live in the world and your conditions. Here in Britain, you’ll often see leeks, parsnips, kale, and much more survive growing outdoors with very little protection at all. In places like the northern United States, you’ll likely see gardeners employ cold-frames, horticultural fleece, and polytunnels to keep their crops alive. Sometimes under heavy snow! I know of one gardener who even keeps the inside of her row covers warm with Christmas lights.
What this means is that your winter garden will be different from many others and that you should research your region. Ask locals, chat to growers at the Farmer’s Market, and think about the conditions that your crops might have to face. Also, what you see people growing and doing on Instagram will not necessarily be what’s right for your garden.
Tools to help Grow a Winter Vegetable Garden
No matter where you live, the winter vegetable garden can be adorned with many props that help to extend the harvest season and keep crops protected. You use an arsenal of season-extending materials to help shield crops against pests and diseases and the harsh winter weather elements. They include stakes, cloches, row covers, netting, hurdles, and mulch.
Cloches are clear plastic or glass domes that you place over plants, creating a mini-greenhouse. Row covers are hooped cloches that span entire rows rather than just an individual plant. they can be plastic or fleece with wire legs that are pushed into the soil. You can also simply lay horticultural fleece over the row, weighing it down with stones or pegs. It’s easy to do and helps raise the soil temperature and humidity. All of these methods protect crops from hungry wildlife and damaging weather.
Tying plants to stakes is another great way to stop plants from being decimated by winds alternatively buy or hand-weave hazel or willow hurdles. Hurdles are essentially windbreaks; natural fencing you can place around your plot to cut down wind exposure. Weaving them is the same principle as making DIY raspberry cane edging.
Growing Winter Vegetables Outdoors
Growing a winter vegetable garden outdoors means you do not have to find indoor or covered space for your crops to overwinter. Nature will help look after your crops and they’ll benefit from winter rain, sun, and airflow. However, overly abundant winter rain can also kill your crop off, so attention is needed. If you have garden beds that are particularly wet and claggy in winter, use other beds that are less so. Also, consider the hours of sun different areas of the garden get. Winter can mean greatly reduced light in general, but winter can be even more extreme. Areas without much sun are colder, wetter, and less hospitable to winter crops.
A benefit to growing outdoors in winter is that some vegetables thrive in cold temperatures. Cold is also absolutely necessary if you want some vegetables to reach their optimal flavor. Hardneck garlic (‘Siberian,’ ‘German Extra-Hardy,’ ‘Lautrec Wight’), kale, and parsnips particularly need a good cold snap. Carrots and turnips (rutabaga) can even taste sweeter after a frost. Hardneck garlic also needs six weeks below 40⁰F (5⁰C) to commence bulb formation. Soft neck garlic (Solent Wight, Early Purple Wight) is more successful in warmer climes and will still grow a bulb regardless of temperature.
Some outdoor-grown plants will also benefit from being wrapped in horticultural fleece. Although this won’t make a huge difference to temperature, this insulation protects against wind and hail. Fleece is a lightweight synthetic material so ensure it is anchored down so does not blow away. Be aware it will raise humidity which can encourage downy mildew and botrytis and when uncovered could attract pests so try mulching with a thick layer of manure or straw which will also help keep the down weeds. Any protection you can use will help plants survive winter.
Growing a Winter Vegetable Garden Undercover
Some tender winter vegetables need protection and added warmth, especially if outside temperatures are freezing. There are various ways you can provide it too: a greenhouse, polytunnel, or cold frame all will create a microclimate raising the ambient temperature, keeping out the elements, and providing a physical barrier to pests. Even a mulched container pushed up against the side of your house can work.
The downside to growing undercover is that you need to give more attention to your crops throughout winter. Plants grown undercover are also more prone to suffer from mildew and disease, so ensuring that they get plenty of airflow is important. Over and underwatering plants is a consideration as is temperature — it can get hot inside a closed greenhouse, sometimes even in winter. There can also be a financial cost attached to each structure.
Winter Vegetable Gardening in a Greenhouse
Greenhouses can make a significant difference to air temperature and they vary in size and cost. You can choose types made from plastic to glass, with frames made of aluminum, wood, or brick. You can choose a size and material that suits your budget, but as someone who has had a polycarbonate greenhouse before, I’d suggest that a better investment is a good glass greenhouse. If you want to plant a winter garden in a greenhouse, it’s better to choose one that won’t blow away!
Cold frames are another very useful tool for helping you to grow a winter vegetable garden. Imagine them as tiny greenhouses composed of brick, straw-bale, plastic, or wooden boxes with a plastic or glass top cover. Though you can place this clear roof horizontally, it’s better to set it at an angle so that rain can run off easily. A sloped top also helps the interior of the cold frame to capture maximum winter light.
Cold frames are perfect for overwintering vegetable seedlings or hardening off before planting outside. In winter, keep them well insulated and they’ll keep crops of lettuce, spinach, chard, beets, and other leafy greens protected through the coldest of temperatures. You can either buy one or build one yourself from recycled materials.
If you have a greenhouse or cold frame then try winter salad such as rocket, mizuna, corn salad, lamb’s ear, endive, or pak choi. You can start Larger winter veg off in modules inside a greenhouse then transplant it outside after being hardened off. These include cauliflower, broccoli, leeks, onions, shallots, kale, and cabbage.
Growing Winter Crops in a Polytunnel
Polytunnels share similar attributes to greenhouses but are different in structure and cost. Consider them large hooped row covers covered in a skin of polythene plastic. This skin needs replacing every five years or so but polytunnels are far cheaper than greenhouses and are the growing structure of choice for many people, including market gardeners. Like greenhouses, they require a bit of space although you can find mini polytunnels on the market.
If you have the space then most winter vegetables could be grown in a polytunnel directly in the soil. It can look just like an outdoor winter vegetable garden but protected by a huge row cover! Always direct sow carrots and parsnips as they do not like root disturbance. You can start Chard, perpetual spinach, and kale in modules to transplant outside or direct sow them. Start Leeks and brassicas in trays or a seedbed; they take a long time to mature so start them early.
Starting Winter Vegetables in Spring
Once the soil and air temperatures drop below 41°F (5°C) plant growth will virtually stop until spring. Your vegetable plants will overwinter in the ground or undercover till you harvest in winter or spring once fully mature. The key to having crops to harvest over winter is early sowing so get planning!
You sow crops that need a long time to mature in late spring or early summer for a harvest throughout winter. Sow Brussels sprouts in April to have sprouts for Christmas whereas leeks need to be sown mid-June. Brussels sprouts and leeks can be started in modules in a greenhouse and planted out when they reach a reasonable size. You can also grow them in a seedbed and transplant them from there. Leeks need a space to expand so make a hole in the ground with a dibber and simply drop your seedling into the hole and water. This is called ‘puddling in.’ Vegetable plants thrive in well-drained rich soils so make sure to add lots of organic manure or homemade compost.
Starting a Winter Vegetable Garden in Summer
Quick-growing crops can be planted in August and September to provide a winter harvest. Salad greens, Asian green vegetables, spinach, turnips, and radish make excellent winter harvests. If grown undercover you can be eating homegrown salad throughout winter.
Ordinary garden radishes have a quick turnaround so are great for the autumn vegetable garden. Winter radishes are different since they’re much larger and need more time to grow. They’re also very hardy! Sow winter radishes in August and harvest throughout winter. Try out the striking and colorful ‘Watermelon’ and ‘China Rose’ or the coal-black skinned ‘Black Spanish’ varieties. Winter radishes can be roasted, or great for crunchy salads, stir-fries, or pickling. The young leaves can also be eaten as a green.
Grow Christmas Potatoes
It’s really a lot of fun to grow your own Christmas potatoes, and kids love them too. Imagine upending a container on Christmas day to find a treasure of tender new potatoes to have for dinner! Start Christmas potatoes either by buying specially prepared seed potatoes or save first earlies from spring in the bottom of your refrigerator. This keeps them dormant during summer, up until you want to plant them in August. Spring and summer harvested potatoes will not grow again until the next year.
Plant tubers in a container inside a greenhouse or polytunnel, planting 1-3 tubers per pot. Grow and earth up as foliage appears, exactly the same as you would with spring and summer potatoes. There’s no need to chit either as the soil is already warm. Grown protected undercover, the foliage should continue funneling energy into the potatoes throughout November. Remove it when it dies down, and leave the container protected with a layer of straw until Christmas.
Harvesting Winter Vegetables
The winter vegetable garden provides hope during bleak months. Early in winter, you can harvest New Zealand yams and mashua, two South American root vegetables. Throughout winter you can harvest leeks, kale, winter cabbage, purple sprouting broccoli, salad, radish, and Brussels sprouts. Leeks and radish should be pulled, outer leaves of kale and salad leaves cut, broccoli cut with a sharp knife at the base of the stalk, and Brussels sprout ‘trees’ can be cut at the base and the individual sprouts snapped off as needed…just in time for a holiday dinner!
If your winter is mild and rarely goes below freezing, you can store root vegetables in the ground. This works for carrots, parsnips, turnips, swedes, beets, kohlrabi, and celeriac. Essentially, you leave them in situ and harvest when needed, saving time and space. The soil protects the roots from the brunt of winter weather but a covering of straw mulch helps protect them too. Pull vegetables as you need them and keep an eye on freezing temperatures. Some crops can be wiped out if temperatures unexpectedly drop.
Overwintering Crops for Next Year
Some winter crops, such as purple sprouting broccoli, spring cabbage, broad beans, kale, chard, perpetual spinach, and garlic overwinter for spring and summer harvests. Their growth slows into dormancy as they weather the elements, waiting, poised for the temperatures to rise in the new year when they break dormancy and spring back into life.
A very sought-after crop that overwinters in the soil is asparagus. Making an asparagus bed is time well spent. Although you have to wait three years to reap the benefits of the harvest, whilst the crowns establish, you can then expect to be annually eating delicious green spears in April for the next 20 years! Once the wait is over, there is very little maintenance with an asparagus bed other than weeding and harvesting.
Cool Season and Winter Gardening Inspiration
As we gently slip into Fall our gardens enter a new phase and as always, there is plenty to keep us occupied. Check out the below tasks for autumn gardening, some winter gardening projects, and ways to protect spring crops from the cold. If you are able to grow in a greenhouse or polytunnel, use a cold frame or cloches, you can extend your growing season whatever the weather and enjoy all-year-round vegetables. Looking ahead, February Garden Jobs will give direction to your garden preparations next year.