Tomatoes are tender perennials, so a plant does not have to die with the first frost. You can bring a potted plant indoors, root a few cuttings or keep a plant in a heated greenhouse until spring. What decides success is bright light, warm temperatures and clean, pest-free plants.
How to overwinter tomato plants: the short answer
To overwinter tomato plants, take 4 to 6 inch cuttings or pot up a healthy plant before nights drop below about 50 °F, cut it back, check it for pests and keep it in a warm spot (roughly 60 to 75 °F) with 12 to 16 hours of strong light a day. Tomatoes are warm-season crops that suffer below 50 °F, as the University of Minnesota Extension and the University of Maryland Extension point out, so a cold garage or basement does not work like it does for other plants.
Contents
- Why overwinter tomato plants at all?
- 3 ways to overwinter tomato plants compared
- Can you overwinter tomato plants indoors?
- Is it worth overwintering tomatoes vs. starting new seeds?
- How to take tomato cuttings for overwintering
- What temperature do overwintered tomatoes need?
- Do tomatoes need grow lights over winter?
- Pruning, watering and feeding in winter
- Choosing the right method
- Limits and common mistakes
- Checklist
- Products for overwintering tomatoes indoors
- FAQ
What to know before you overwinter tomato plants
Unlike peppers or geraniums, tomatoes do not go into a real dormant rest. They keep growing as long as they are warm, which means they need light and care all winter. Plan with three questions: Do you have a bright, warm spot? Is the variety worth keeping? And are the plants healthy?
Why overwinter tomato plants at all?
The main reason is to keep a variety you cannot easily buy again, such as a hybrid you liked, a gifted plant or a rare heirloom whose seeds you did not save. Hybrids (F1) also do not grow true from saved seed, so a cutting is the only way to get an identical plant. A second reason is a head start: a rooted cutting from winter can be a sturdy transplant by spring.
3 ways to overwinter tomato plants compared
- Cuttings (recommended): root 4 to 6 inch side shoots or tips in water or potting mix. Pros: little space, young and vigorous plants, fewer pests. Cons: they need strong light for months.
- Whole potted plant indoors: dig or bring in a container plant and cut it back. Pros: some fruit may keep ripening. Cons: a large plant needs a lot of light and space and often brings pests inside.
- Heated greenhouse: keep plants growing in a greenhouse heated above about 55 °F. Pros: the most natural conditions. Cons: heating costs and low winter daylight still limit growth.
Can you overwinter tomato plants indoors?
Yes, you can overwinter tomato plants indoors if you can give them warmth and enough light. A south-facing window is often too dim in December and January, so most plants grow weak and leggy without additional light. Small plants from cuttings are much easier to keep than a full-size plant from the garden.
Determinate (bush) tomatoes stop growing after they set their crop and often decline after one season. Indeterminate (vining) varieties and cherry tomatoes are usually better candidates for overwintering.
Is it worth overwintering tomatoes vs. starting new seeds?
For most common varieties, starting new seeds in late winter is easier and gives equally good plants. Overwintering is worth it when you want to keep a specific hybrid, a plant without seeds or simply want to experiment. Older plants also carry more risk of diseases and pests, so only overwinter plants that were healthy all summer.
If you prefer to start fresh from seed outdoors, our winter sowing guide shows a low-effort method for hardy crops; tomatoes themselves are usually started indoors 6 to 8 weeks before the last frost.
How to take tomato cuttings for overwintering
Take tomato cuttings by cutting 4 to 6 inch side shoots (suckers) or stem tips from a healthy plant, removing the lower leaves and placing the stems in water or moist potting mix. Roots usually appear within one to two weeks at room temperature.
- Choose healthy, non-flowering shoots before the first frost.
- Cut just below a leaf node with a clean blade.
- Remove leaves from the lower half and any flowers.
- Place in a glass of water or bury the bare stem 2 to 3 inches deep in moist mix.
- Keep warm and bright, but out of hot direct sun for the first days.
- Pot rooted cuttings into 4 inch pots once roots are 1 to 2 inches long.
Take a few more cuttings than you need. Some will be weak or rot, and you can always choose the strongest two or three plants in late winter.
What temperature do overwintered tomatoes need?
Overwintered tomatoes do best at about 65 to 75 °F during the day and not below 55 to 60 °F at night. Below roughly 50 °F, tomatoes can suffer chilling injury, and growth almost stops. Keep pots away from cold drafty windows at night and away from heating vents that dry the air.
In a greenhouse, a thermostat-controlled heater such as the PALMA Electric Greenhouse Heater (110 V) can hold a set minimum temperature. Non-electric methods from our guide on heating a greenhouse without electricity are usually not enough to keep tomatoes warm through a cold winter.
Do tomatoes need grow lights over winter?
In most of the US, yes: tomatoes need grow lights over winter because short days and weak sun do not give them enough light to stay compact and healthy. Aim for 12 to 16 hours of light per day with the lamp close to the plant, and use a simple timer.
For one or two plants, a single full-spectrum LED is enough. The FLORABOOSTER 500 plant lamp is a pendant light with a 6.5 watt full-spectrum LED that hangs directly over a pot, and the FLORABOOSTER 505 bulb fits a standard medium (E26) base in an existing lamp. Small LEDs like these support a few small plants or cuttings; they are not designed to bring a large plant into full fruit production. Read more in our article Can plants grow in LED light?
Pruning, watering and feeding in winter
Cut a potted plant back by about one half to two thirds before bringing it in, and remove damaged, yellow or spotted leaves. Water when the top inch of soil is dry, and feed lightly every four weeks only if the plant is actively growing under lights. Too much fertilizer with too little light produces soft, leggy growth.
Indoors there are no insects to pollinate flowers. If you want fruit in winter, gently shake flowering stems or tap them every few days.
Choosing the right method
- Little space, keep a variety: two or three cuttings under a small LED.
- Plant still loaded with fruit: bring the pot in, cut back lightly and let the fruit ripen, then decide.
- Heated greenhouse available: keep a few plants growing there, protected by a thermostat.
- Common variety and no light: skip overwintering and sow new seeds in late winter.
Limits and common mistakes
- Bringing in pests: whiteflies, aphids and spider mites multiply fast indoors. Check the undersides of leaves and quarantine plants for two weeks.
- Overwintering sick plants: plants with blight or leaf spot should go in the trash, not indoors.
- Too little light: pale, stretched stems mean the lamp is too weak or too far away.
- Cold storage: a garage or basement that works for dormant plants is too cold for tomatoes.
- Overwatering: slow-growing winter plants need far less water than in summer.
The overwintering steps for peppers are different because peppers can rest in a semi-dormant state; see how to overwinter peppers. For flowers, read how to overwinter geraniums, and for your outdoor beds, how to winterize raised garden beds.
Checklist for overwintering tomato plants
- Act before nights fall below about 50 °F
- Choose healthy indeterminate or cherry varieties
- Take 4 to 6 inch cuttings or cut potted plants back
- Check for pests and quarantine for two weeks
- Keep 65 to 75 °F by day, at least 55 to 60 °F at night
- Provide 12 to 16 hours of light per day
- Water sparingly, feed lightly only with active growth
- Harden off and plant out after the last frost
Products for overwintering tomatoes indoors
FAQ
Can tomato plants survive winter outside?
No. Outside of frost-free areas, roughly USDA zones 10 to 11, tomato plants die at the first frost and suffer below about 50 °F.
How long can an overwintered tomato plant live?
Under good conditions, indeterminate tomatoes can live and produce for two or more years, but yields often decline and the risk of disease grows with age.
Can you overwinter tomatoes in a dark basement or garage?
Not reliably. Tomatoes do not go fully dormant, so dark, cold storage usually kills them. They need warmth and light.
When should I plant overwintered tomatoes outside?
After the last spring frost, when nights stay above about 50 °F. Harden plants off outdoors for 7 to 10 days first.
Overwintering tomato plants is a small project that lets you keep a favorite variety and start spring with a ready plant. With warmth, a simple LED grow light and a timer, a few cuttings can make it through the darkest months.