If you’ve ever asked yourself Can tomato plants survive winter? the answer is a resounding yes. In their native tropical growing range, tomato plants are perennials that live for many years. In cold climates, however, they do not survive winter outdoors because they are not frost-tolerant. Because of this, most gardeners grow tomatoes as annuals. We plant them in the spring after the danger of frost has passed, harvest them through the growing season, and then uproot and compost the plants as soon as they’ve been killed by freezing temperatures. But if you’re willing to put in a little effort, tomato plants can live and produce for many years. In this article, I’ll share four ways you can overwinter tomato plants and keep them from year-to-year.
How to keep a tomato plant alive in winter
After putting in tons of effort to grow healthy and productive tomato plants throughout the growing season, it’s always a heartache to watch them succumb to freezing temperatures. So if you want to know what to do with tomato plants in winter, you first have to understand the importance of good timing. Waiting too long to begin your tomato overwintering efforts reduces your chances of success. Start focusing on overwintering about four weeks before your first expected fall frost. Here in Pennsylvania, I start making a plan to overwinter a few tomato plants around mid to late September.
Four weeks prior to your expected first frost, it’s time to think about which one of the four techniques featured below will work for you, your family, and your home. Not all of us have grow lights or a greenhouse, so those methods might not work for everyone. But most of us have a garage, a basement, or a sunny windowsill, so there’s sure to be an option available for all gardeners. Once I’ve settled on which approach I want to take, I begin to prepare my plants.
How to prepare tomato plants for overwintering
I also start watching the forecast very carefully about four weeks before the arrival of a typical first frost. If I get an unexpected premature frost and cold weather arrives earlier than expected, I could lose my tomato plants to a surprise freeze, and there go my chances of overwintering them. It’s much better to start to overwinter tomato plants early than it is to wait too long and be caught with your proverbial pants down!
Prepare plants by making sure they are kept well-watered for at least a few weeks prior to transitioning them. During that time, remove any diseased leaves from the plant and make sure there are no pests present. If you find whiteflies, aphids, caterpillars, or other damaging insects, get them under control before trying to overwinter your plants.
If you plan to use one of the first two methods described below and your tomato plant is currently growing in the ground or in a raised bed, you’ll need to dig it up and transplant it into a pot. Use new, sterile potting soil and try to get as much of the root mass as possible. Keep the pot on an outside porch or patio for a week to 10 days and make sure it receives regular deep irrigation. If the plant is already growing in a pot, great. Your job is much easier. You can skip the transplanting step.
4 ways to overwinter tomato plants
As you’re about to learn, the question Can tomato plants survive winter? has an easier answer than you might think. Here are details on four techniques you can use to keep your tomato plants safe and sound through the winter months. Use just one method or try all four and see which one works best for you. Don’t be afraid to experiment; you have nothing to lose. Your tomato plants were going to succumb to frost anyway, so why not take a chance and try overwintering them instead?
Method 1: Overwintering tomato plants in your house
When thinking about how to overwinter tomato plants, the most common thought running through a gardener’s mind is, Can I bring my tomato plant inside for the winter? Yes, in short, you can. Tomatoes can be grown indoors as houseplants for the winter, though they may not develop flowers or fruits if they don’t get enough light (see section below about how to act as an artificial pollinator if they do produce flowers). This technique is best for determinate tomato plants, dwarf tomato varieties, micro dwarf types, or those that can be kept compact through regular pinching and pruning.
Can tomato plants survive winter indoors if you grow them like a houseplant? Absolutely. But they do have some specific requirements. The main downside to this overwintering method is that indoor tomato plants need a lot of sunlight. Yes, you can put the pots on a bright windowsill, but even in the brightest window, in most cases they will survive the winter with just a few scraggly leaves. In the northern hemisphere, our winter days aren’t long enough, and the winter sun is not intense enough, to give tomatoes all the light they need. It’s much better to attempt this method if you have a grow light.
Thankfully, there are many affordable, compact, and high-quality grow lights on the market these days. Floor lamp-style models fit nicely into a corner of the room. A shelf of LED grow lights works if you have multiple tomato plants to overwinter and they are compact or dwarf types that don’t grow very tall. Run the lights for 18 to 20 hours per day. Watch carefully for pests as they find indoor tomatoes very appealing and may piggyback in on the plant’s foliage.
Come spring, slowly transition your overwintered plants back into the garden by gradually increasing the amount of time they spend outdoors each day over a period of two weeks. Then, plant them out into the garden (or into a larger pot), give them a haircut down to half of their height, and begin to water and fertilize them regularly. It will give you a slight jumpstart on the growing season and, perhaps more importantly, it will enable you to save a favorite variety from year to year.
Method 2: Growing tomato plants in a winter greenhouse
If you’re lucky enough to have a greenhouse and a greenhouse heater, tomato plants can easily be overwintered inside. Some gardeners grow their tomatoes in a greenhouse or high tunnel throughout the entire growing season so that when the autumn weather grows colder, they merely have to close up all the vents and turn on the heat in order to protect the plants. You don’t need to have the temperature cranked way up; anything above freezing will serve to overwinter the plants. But, if you want them to produce flowers and fruits in the winter, you’ll need to aim for more tropical-like temperatures all winter long, which can be quite costly to achieve.
Whether you grow hybrid tomatoes like ‘Early Girl’ or heirloom types like ‘Brandywine’, overwintering in a greenhouse is a viable option. Determinate tomatoes and other more compact types are easier to fit in smaller greenhouses. You’ll need to use stakes or a cage to support each vine through the winter as their stem growth can become soft and tender in the lower light levels of winter.
If you do want to try to get the plants to produce fruits in the winter, in addition to playing pollinator, you’ll have to add nutrients through the application of liquid fertilizers on a regular basis, perhaps every four to six weeks. But if you merely want to see the plants safely through the winter, do not fertilize as it will generate excessive leafy growth that isn’t necessary during the colder months.
Method 3: Overwintering tomatoes as stem cuttings
This is one of my favorite ways of keeping tomato plants alive in winter. It doesn’t require much room and anyone can do it. All you need is a jar or plastic container of water and some tomato stem cuttings.
Before the first frost, cut 3- to 5-inch-long pieces of stem off of your tomato plants. The terminal portion of each stem is the best. Alternatively, you can use the suckers produced at the leaf nodes as your cuttings. Remove all but the topmost leaf or two from each cutting and stick the cut end down into a container of water. Label it with the variety name and place the container on a bright windowsill (the brighter the better).
Within a few weeks, the cutting will form roots. Your goal for the rest of the winter is to keep the cutting alive by following these steps:
- Every two weeks, take the cutting out of the jar, rinse the roots under running water, and wash and refill the container with fresh water. Put the cutting back into the water.
- Every six weeks, cut off the top 3 to 5 inches of the cutting to make a new cutting. Follow the same process as above to root the new cutting. Now you have two cuttings. The original one (with the top now cut off) will develop side branches. The second cutting can have its top cut off in another six weeks to make a third cutting.
- About four to six weeks before your last expected spring frost, pot each of the cuttings into a fresh pot of sterile potting soil, planting them as deeply as possible. Put these potted cuttings onto a very bright windowsill or under grow lights. Turn the pot a quarter turn every day to keep the growth even. Do not fertilize them if you’ve chosen a potting soil that already contains fertilizer.
- Once the danger of frost has passed, slowly acclimate your plants to outdoor growing conditions by following these hardening off instructions. Then, plant your rooted cuttings out into the garden.
By overwintering tomato plants via cuttings, instead of planting seedlings at the start of the next growing season, you’ll be planting tomato cuttings taken from last year’s plants. This method can be performed with indeterminate tomato plants or determinate varieties.
Method 4: Keeping tomato plants in bare-root dormancy for the winter
For some reason, this old-school method of keeping tomato plants alive in winter isn’t as popular as it should be. Maybe the practice was abandoned when it became easier to purchase new tomato seeds or plants each season. Regardless of the reason, I would love to see this method come back into popularity. It’s surprisingly easy, and most importantly, it results in an earlier harvest. With this method, the answer to Can tomato plants survive winter? is turned into a fun experiment for the whole family.
This technique involves overwintering tomato varieties in a state of dormancy where they have no soil on their roots (bare-root). It can be done in a cool garage, a cold cellar, or a basement that stays barely above freezing all winter long. You can even store the bare-root plants in the fridge, as long as you don’t keep your temp set too low. Let me explain how to perform this method of overwintering tomatoes.
- Step 1: Just before a frost is predicted, uproot the entire plant. There’s no need to be gentle about the process but do try to keep as much of the root system intact as possible.
- Step 2: Cut each vine back to about a foot in length so the plant is just short, bare stems without any foliage.
- Step 3: Use a soft brush or your hands to remove as much of the soil from the roots as possible.
- Step 4: Wrap the roots around your hand to form a loose circle of roots. Lay the plant down on a table with the circle of roots sitting on top of a square of cotton fabric or a piece of an old T-shirt with some slightly damp shredded newspaper, sheet moss, or even vermiculite on it.
- Step 5: Wrap the circle of roots tightly in more slightly damp shredded newspaper, sheet moss, or vermiculite.
- Step 6: Wrap the cotton fabric around the wad of damp paper or moss to keep it in place, and then use a piece of string or a zip tie to secure the whole thing around the roots.
- Step 7: Surround the wrapped root mass with a tight layer of plastic wrap or a repurposed plastic grocery bag. If you don’t like using plastic, waxed fabric works, too.
- Step 8: Put the whole thing in a brown paper bag and close it tightly. You can keep multiple plants together in a single paper bag. (If you try this method, and the plant shrivels up and dies before spring, your environment may be too dry. If this happens, in the future, fill the bag with very slightly damp peat moss to fully surround the stems prior to storage.)
- Step 9: Put the bag on a shelf in a cool garage, root cellar, or basement. Alternatively, you can stick it in the fridge (a crisper drawer with high to moderate humidity is best, but not necessary).
- Step 10: Remove the plant every six weeks and check to be sure the materials wrapped around the roots are still damp. If not, use a mister or spray bottle to wet them. Then rewrap the roots and put the whole thing back into storage.
In the spring, you can bring the tomato plants out of storage and pot them up about six weeks before your last frost date. Or you can keep them in dormancy right up until the danger of frost has passed. Then plant them directly out into the garden.
This way to overwinter tomato plants gives you a great head start. Plus, it’s especially useful for indeterminate tomatoes that are otherwise too large to overwinter.
Can tomato plants survive winter? The final requirements
If you want to keep tomato plants year-round, there are just two other factors to consider.
- Tomato flowers are self-fertile, but in order for tomato flowers to develop into fruits, the pollen within the flower must be knocked loose. Out in the garden, wind or visiting bumble bees perform this duty. But in your house or a greenhouse where no pollinators are present, you’ll have to act as pollinator. Take a cheap electric toothbrush and place it against the stem of the flower, just beneath the base of the bloom. Hold it there for about three seconds. Repeat the process three days in a row for each new blossom that opens. Can tomato plants survive winter? You bet! But will they produce fruits? Well, as you can see, that’s partially up to you.
- If you have enough light, you may have fruits develop on your plants (or maybe there were already some green tomatoes on the plant when you brought it inside). I’ve found that the fruits don’t always ripen naturally indoors. The conditions just aren’t ideal. So instead, I pick the fruits green and hasten the ripening process by putting them into a paper bag with a cut apple. The apple releases ethylene gas which is a natural plant hormone that encourages the ripening process.
Give it a try
Now that you know the answer to the question Can tomato plants survive winter?, I hope you’ll give some of these methods a try. It’s a great way to save money, preserve treasured varieties, get a jump start on the next growing season, and have fun experimenting.
For more on growing a bumper crop of tomatoes, please visit the following articles:
- How to make tomato plants grow faster
- Tomato growing secrets
- What to do about tomato suckers
- Companion plants for tomatoes
- Tomato caterpillar pests
- Supporting tomato plants
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