Easy Ways You Can Keep Tomato Plants Over Winter

As a gardener, you may want to keep tomato plants over winter, so they can be replanted or continue growing the following spring. This can be done indoors, in a greenhouse, or possibly even in your existing garden beds. Your first frost doesn’t have to be the end of your tomato season after all.

The Benefits of Keeping Tomato Plants Over Winter

 Here are some of the key benefits of overwintering tomatoes that are especially useful for those who live in regions with harsh winters, where tomatoes wouldn’t normally survive outdoors:

1. Early Harvest: By overwintering your tomatoes, you can start with mature plants in the spring, allowing for a much earlier harvest compared to planting seeds or young seedlings.
2. Extends the Growing Season: Overwintering allows you to extend the growing season, particularly in colder climates, where tomatoes wouldn’t survive outdoors during winter.
3. Cost Efficiency: Instead of buying new seedlings or seeds every year, you can save money by overwintering existing plants.
4. Stronger Plants: Older, well-established plants can become hardier and more resilient to pests and diseases than new plants. Overwintered plants may produce larger and more robust yields the following year.
5. Preserving Favorite Varieties: If you have a specific tomato variety that you love and that may be hard to find, overwintering ensures you can keep it going year after year without relying on seeds.
6. Continuous Fruiting Indoors: If the conditions are right (sufficient warmth and light), overwintered tomatoes can sometimes continue to produce fruit indoors during the winter months.
7. Disease Management: Overwintering in a controlled environment reduces the risk of diseases that might occur in soil or outdoor conditions, allowing you to nurture the plant more carefully.

Tomatoes as Perennial Plants

​Did you know that in tropical parts of the world, tomato plants are perennial plants? They don’t see freezes that kill them, so they continue to grow season after season as long as they remain healthy.

You too can keep a perennial tomato plant by tending to it in place, right in your existing garden bed. Simply protect it from any danger of frost or freeze, and your plants will happily keep growing. 

They may not produce fruit with reduced daylight exposure, but they’ll bounce back fast in Spring and provide your first fruits long before your annual plants produce.

How to Prepare Tomato Plants for Overwintering

​To begin, prune back to reduce the size of the whole plant and remove any damaged, dead, or diseased leaves. You may want to cut the plant down by about half to make it more manageable.

Check the plant thoroughly for pests such as aphids, spider mites, or whiteflies, to ensure that you’re starting with a healthy plant.

What to Do for Your Tomato Plants During the Winter Months

Consider these options to overwinter tomatoes from your garden:

• keeping indoor tomato plants
• using a heated greenhouse
• continuing to grow tomato plants as perennials

1. Keeping Indoor Tomato Plants

You can dig up the plant and transplant it into a large pot if it was growing in the ground. Use fresh, high-quality potting soil to reduce the risk of soil-borne pests and diseases. The last thing you need is to bring pests into your home.

Tomatoes are tropical plants and need warmth to survive. Keep them in a room that stays between 65-75°F (18-24°C).

Tomatoes need full sun, so place them in a sunny window (southern exposure works best) where they can get at least 6-8 hours of light daily. Alternatively, you can use grow lights to supplement the natural light when you keep tomato plants over winter.

The air indoors during winter can be quite dry, so it helps to keep the humidity levels moderate. A humidity tray or a small humidifier can help if needed.

Water the plant just enough to keep the soil lightly moist, but avoid overwatering. The plant won’t need as much water as it does in the growing season.

If your tomato vines are still producing some growth, you can feed the plant occasionally with a little bit of diluted liquid fertilizer, but don’t overdo it since the plant will be in a semi-dormant state.

If you’re in a southern region, where winter temperatures can rise upwards of 70 degrees fahrenheit during the day, it’s a good idea to move your tomato plants outdoors on warm days. This will give you a better chance at actually growing fresh tomatoes during the winter months.

2. Growing Tomato Plants Over Winter in a Heated Greenhouse

Of course growing in a heated greenhouse will help to keep your tomatoes nice and toasty during the winter months. However, a greenhouse or high tunnel isn’t feasible for most backyard growers. 

That’s okay. You can create a small heated greenhouse of your own with some cheap fencing, posts, and clear plastic sheeting. Make sure that the foliage of your plants doesn’t touch the plastic sheeting or they’ll freeze when temperatures drop below 32°F (0°C). 

Add a heat source, such as incandescent Christmas lights, under the plastic tent that you’ve made to keep your tomato plants over winter from freezing.

Make sure that you open the makeshift greenhouse if daytime temperatures rise so that your plants don’t burn.

3. Overwintered Plants Using the Bare-Root Dormancy Method

Using the bare root dormancy method to overwinter tomato plants is a practical and space-saving approach. In this method, the plant is allowed to enter dormancy (a state where it’s not actively growing) by storing it without soil. The plant’s roots are kept bare and preserved through the winter, then replanted in the spring.

To start, choose clean, undiseased plants as previously mentioned with the other methods. 

Then, cut back the tomato plant to about 6-8 inches  above the base. Remove any flowers, fruit, or dead/diseased leaves. This helps reduce the plant’s size and prepares it for dormancy.

Gently clean off any remaining soil from the roots by lightly rinsing them with water. Be gentle to avoid damaging the roots.

Storing Bare Roots

Bundle the roots together with a loose string or twine. Make sure the roots have some space to breathe and aren’t packed tightly. Wrap the roots in damp paper towels, sphagnum peat moss, or sawdust to keep them moist but not wet. 

Next, Place the plant in a breathable plastic bag, burlap sack, or cardboard box. Poke holes in the bag or box to ensure airflow. Store the wrapped tomato plant in a cool, dark area such as a basement, garage, or cellar. The ideal storage temperature is between 40-50°F (4-10°C). Avoid freezing temperatures. 

Check the moisture level of the material around the roots (paper towels, moss, etc.) every few weeks as you keep bare-root tomato plants over winter. If it’s drying out, lightly mist it with water to keep it slightly damp. Avoid letting the roots dry out completely. Also, make sure they aren’t rotting or developing mold. If any sections appear diseased or damaged, cut them off.

In early spring, around 6-8 weeks before the last expected frost, take the dormant tomato plant out of storage. Soak the roots in lukewarm water for a few hours to rehydrate them. This helps jump-start the plant’s growth.

Plant the tomato in a pot with fresh potting soil. Water the soil lightly and place the pot in a sunny, warm location or under grow lights.

4. Overwinter Tomato Plants With Stem Cuttings

In late fall, cut 4-6 inch (10-15 cm) long sections of the healthiest shoots, making sure each main stem has a few leaves. Place the cuttings in a jar of water, making sure the lower leaves are removed from the section that will be submerged. 

Put the cuttings in a bright, warm spot. Change the water every few days. After about 1-2 weeks, roots should begin to develop.

Once the tomato cuttings have established roots (usually within 2-3 weeks), you can transplant them into pots with fresh potting soil. Keep the pots in a warm, sunny location, or use grow lights to ensure they get enough light.

Watch out for fungal diseases and white flies as you attempt to store tomato plants over winter. If you notice these becoming a problem, you can use neem oil spray on your plants.

Once new growth starts to appear and the risk of frost has passed, begin hardening off your favorite tomato plant by slowly introducing it to outdoor conditions over 7-10 days. Transplant the tomato plant back into your vegetable garden or outdoor containers.

​Choosing Cold Hardy Tomato Varieties

Cold-hardy tomato varieties are specially bred to withstand cooler temperatures and shorter growing seasons. Using these varieties makes keeping tomato plants over winter easier. Here are some of the best cold-hardy tomato varieties:

1. Stupice
2. Glacier
3. Siberian
4. Sub-Arctic Plenty
5. Oregon Spring
6. Polar Baby
7. Early Girl
8. Manitoba
9. Northern Lights​

 Final Tips to Keeping Tomato Plants Over Winter

• Keep an eye on the plant’s leaves for any signs of stress, disease, or pests.
• Regularly rotate the pots to ensure even light exposure.
• If the plant starts to look leggy due to insufficient light, try adjusting the light source or adding a grow light.
• Once the last frost has passed and temperatures have warmed up in spring, you can begin hardening off the tomato plants by gradually exposing them to outdoor conditions. After 7-10 days of gradual exposure, you can plant them back into your garden or outdoor containers for much earlier tomatoes.

By following these tips and tricks, you too can appease your tomato-loving heart by successfully keeping tomato plants over winter. Consider using your old tomato plants to get a jump start on next year’s garden now.

Happy Tomato Gardening!

Donna and her family have been homesteading for most of their 20+  years together in some shape or fashion. She currently lives on their 20 acre farm where they grow as much food as possible. What started as a just a few laying hens, has grown into large gardens, pastured poultry, pork, and lamb. They are continuously evolving their small farm to not suit their family’s needs, but also providing to their local community. Donna’s favorite part of the family farm is her self-built micro-dairy, where she gets to love on dairy cows while serving her local community. Milking, cheesemaking, and processing dairy have become the soul of their homestead and the center of their farm.