As I was researching how to prepare you garden for winter, I realized a lot of websites did not provide specifics on which vegetables actually could grow in the winter, the temperatures that they could thrive in, what “over wintering” meant, how do I know if my plant can even go “dormant,” and several other specifics. I decided that I needed to do some more research and share what I found.
Can I grow vegetables in the winter time?
What a complicated question. Yes and no. This changes based on your location, how cold your fall and winter are for that particular year, and what type of plant you are growing. Unfortunately for many of us who live in climates that reach 15 degrees or colder over night, those temperatures really kill your plants.
The USDA has made a great map that shows the zone you live in. These zones divide the country by average temperatures. If you are even looking at this article, you probably already know about these zones. Here is a reference map anyways:
This map is a little generalized from the Urban Farmer. I would check out the USDA’s more comprehensive map, but this map will let know you if you can grow plants during the winter. Basically anyone in zone 5 and up are unable to grow “winter” vegetables much past October, due to very cold nights. Zone 6 is questionable. There are ways to protect your plants in these climates. Read about this later in my article.
What types of plants are “winter” vegetables?
Note: As stated from above, these vegetables cannot just be grown willy-nilly. They also die when it becomes cold. For many of us who live in the northern 30 states, winter gardening can seem impossible. There are methods though that I will speak to later on. If you are lucky enough to live in an area that does not become colder than 30 degrees F, then you can essentially plant all year round. Just make sure you are giving your soil a break and restoring nutrients. Click the links to see growing instructions on each plant.
Vegetables that live through a light frost and their varieties (30-32 degrees F)
- Onions – all varieties but they will need 12-15 hours of sunlight for large bulbs
- Garlic – softneck garlic: Burgundy, Susanville, Red Toch. Hardneck varieties: German White, Spanish Roja, Chesnok Red
- Spinach – Winter Bloomsdale, Emperor, Giant Winter, Tarpy Spinach (with a row cover)
- Cabbage – Cheers, King Cole, Savoy King and Queen, Red Ruby Ball and Meteor
- Radishes* – all varieties, try Tinto or Cherry Bell, d’Avignon
- Beets – Detroit Dark Beet
- Potatoes – all varieties
- Chard* – try Blue Max, Perpetual
- Collards – Vates, Champion, Morris Heading
- Lettuce* – Red Salad Bowl, Oakleaf, Salanova
- Mustard – all varieties
- Leeks – most varieties, try Lexton
Vegetables that live through several frosts (Must be above 20 degrees F)
- Broccoli – calabrese and other common varieties
- Cabbage – Early Jersey Wakefield Cabbage, Bok Choy, Napa, Savoy,
- Cauliflower – white, orange, purple
- Carrots* – Nelson, Mokum, Napoli
- Brussel Sprouts -Diablo, Nautic (okay)
- Turnips* – White Egg, Colletto Viola, Hakurei
- Rutabagas – White or Purple Kohlrabi
- Kale – Red Russian, Siberian
- Parsnips – All American, Harris’ Model, Hollow Crown
* These vegetables can be more difficult to grow.
If for some reason you cannot find any of these specific varieties, do not stress over it. Find a variety you think you will like and then research it. This list is just pre-researched to be especially hardy in the winter. I had a lot of success looking at Johnny’s Selected Seeds. This company sells plant varieties that are already researched to grow well in colder climates.
Make sure to follow the directions on each of these links, and do not grow them past the temperatures mentioned above. All of these plants germinate (or seed to start to sprout) better if they are started indoors. Most seedlings need about 60 degrees F to start growing. Most of these plants should be okay with the limited sunlight received during winter months. (Now if you are in Alaska when it is dark all day long, perhaps you should look into a plant light…)
How to I grow these vegetables if my “zone” or location is too cold?
This is a significant problem for many farmers. For of us gardeners, by October, we are feeling zero degree evenings. Our “winter” gardening will tend to be a late fall harvest. While these plants may survive the snow, they won’t last much longer than that. There are some ways to combat these cold temperatures.
The best way to ensure that you can continue growing is to use some type of cover. After some research, I found a man named Eliot Coleman, who is an expert at growing plants all year round. I initially found a website called Cold Garden who spoke of his work. He says that each cover on the garden is like moving your garden 500 miles south. So… according to his math, you could assume that in temperatures around 30 degrees F (or the cut off temperature first winter vegetables list), you would need at least one cover.
A cover will keep the heat in the soil and keep the cold air out. Frost forms from moisture at temperatures around 32 degrees F. However, if you are experiencing very cold evenings and warmer days, you may have to cover at night, and then remove for the warmer day time. This can be a tricky game to play with your plants. You’ll need to check the weather often to ensure that your plants will not roast or freeze. You can buy an automatic cover for a reasonable price.
Garden covers are just to create insulation between the plant and the air. The idea is to keep the soil temperature from fluctuating and keep frost off the of the leaves. Greenhouses create a warm environment for plants to thrive and grow. Make sure you are using white plastic and not clear. Clear will create a lot of heat. The process of heating and cooling plants will slowly cook them into mush.
If you are growing north of Zone 5, you will want to have a cover inside of a greenhouse. This is a little more tricky, but it will provide you with the warmth your plants need. You will want to read Eliot Coleman’s book, The Winter Harvest Handbook: Year Round Vegetable Production Using Deep-Organic Techniques and Unheated Greenhouses. This will give you all the necessary ins and outs to help you use a double cover successfully.
What other options do I have?
Move your plants indoors
If greenhouse gardening is not for you, you may consider potting your plants indoors. This can also be a little tricky. Make sure you have the right size pot, you receive enough sun light from your window (or have a plant light), and that your house is the right temperature for the plant you are growing.
All potted plants that were outside need to be moved indoors. These unfortunately will not benefit from warm soil temperatures. There is just not enough soil to provide heat.
Many people enjoy sprouting. This basically just placing seeds or beans in water and allowing them to germinate a little. This is a very simple process and is fun to do in the winter time! This is also a great way to be prepared with fresh greens. You can store seeds and beans with your food storage. These cannot be stored with oxygen absorbers though. The absorbers kill their potential for germination.
Allow your plants to go dormant
You may also consider having your plants go “dormant” in the winter. If your plant was able to grow strong roots, and is a perennial (is able to come back each year), it will go dormant all by it’s self! This just means that it will appear to be dying, but keep it’s roots alive.
The trick here it to keep the soil from becoming too cold. Placing a layer of mulch or hay will keep the soil warm enough for the roots. You may need a very thick layer, or mulch and a ground cover. If your temperatures dip below zero, I would definitely do both. Additionally, since mulch will keep the moisture out of the soil, once a month you’ll need to add some moisture into the soil.
Once the threat of freezing temperatures are gone, you can remove the mulch, and some fertilizer, and allow the plant to grow. This can ensure some early vegetables for your family. This is also an excellent way to be stay prepared with fresh food for your family.
All of the cold hardy plants listed above will produce early in the spring. Warmer plants may not be hardy enough to bounce back in the spring. Other examples of perennials are: rhubarb, asparagus, chives, broccoli, potato, sweet potato, and watercress. Research your variety to ensure it is a perennial.
Create a “root cellar”
Most cold weather hardy plants can be either pulled from the ground, flipped up so the the roots are in the air, and then be stored under about a foot of dirt. This allows them the stay fresh through out the winter without preserving them in some other way. They would also need a layer of dirt on top of them as well. Placing some type of a marker will allow you to find you plants through snow, mulch, and dirt. Examples of vegetables that do well with this are cabbages, potatoes, and other root vegetables.
Plant a cover crop
Planting a cover crop ensures that your dirt will not erode, your soil is renewed, and gives you a break from gardening. Some people have started to use radishes as a cover crop. You may want to consider something like clover, because it add nitrogen back into the soil.