Tomato plants are actually perennials, but they are frost-tender and don't usually survive the winter here in the United States. But I've had success over-wintering cuttings from my plants indoors. Here's how to over-winter your tomato cuttings for a head-start in the spring.
How to over-winter tomato plants without a greenhouse
What if you could grow tomatoes year-round, no matter where you live?
Although tomatoes are technically a perennial, they are grown as annuals here in the US.
(By the way, this post was originally written in 2012,
but was revised, rewritten and updated in October 2022.)
Ever since I first read about a huge, perennial tomato plant in Walt Disney World's Epcot Center, which supplies the tomatoes for the theme park's restaurants, I've been intrigued. The photo in the article showed a plant that resembled a tree!
AND it's perennial!
What if it could be possible to keep a tomato plant alive over the winter?
After researching that particular tomato plant, I could only find that it grew in a greenhouse and "lived more than a year."
The author wrote that it produced a record-breaking harvest. I was more interested in its longevity but evidently the large harvest was much greater news.
I decided to embark on an experiment!
Gardening is just one big experiment, you know. Or maybe a series of experiments.
Over-wintering tomato plants in a greenhouse
Gardeners who are fortunate enough to have a greenhouse often bring in their tomato plants before the first frost so they can have vine-ripe tomatoes late in the autumn.
They also start their tomato seeds in very early spring so they'll have big healthy plants ready to go in the ground when the weather is warm enough.
How wonderful would that be?
But I don't have a greenhouse - and it wouldn't be warm enough in a greenhouse in the middle of winter to keep a tomato plant going without a heat source.
I have friends with hoop houses here in Oklahoma, but a hoop house isn't warm enough to keep a tomato plant alive in the depths of winter either.
So, at least for me, the possibility of moving tomato plants into a greenhouse wasn't possible.
Over-wintering tomato plants indoors
You could keep a tomato plant alive all winter if you grow it in a container that you could move indoors before the first frost.
It might or might not produce fruit during the winter, depending on the temperature of your house and the amount of light the plant receives.
Tomato plants prefer daytime temperatures of 70° to 85ยบ Fahrenheit, with night-time temperatures between 59° and 68°F. [Source]
As for container size, bigger is better. A five-gallon bucket is a good size for one plant. Containers must have drainage holes so the plant isn't sitting in water. Tomato plants hate having "wet feet."
Tomato plants kept indoors should have a shallow saucer or other container underneath the pot so excess water won't ruin your floors or furniture.
Over-wintering tomato cuttings
It's super easy to take cuttings of tomato plants and root them in water. You almost can't fail, although some varieties of tomatoes will root more easily and successfully than others.
So I began to wonder: if I take cuttings of my plants before the first frost, and root them in water, could I keep them alive all winter on a sunny windowsill?
After the cuttings develop roots, they should be planted in soil. They will continue to grow in water, but they will get very leggy and outgrow their jar or glass of water long before spring arrives.
OR, I wondered, if they grew too tall, maybe I could take cuttings of the plants growing in water on my windowsill and root them in water.
I wondered if I could do this over and over and have healthy plants to put in my garden as soon as it was warm enough in spring?
These plants wouldn't really be "perennials" in the strictest sense of the word. It isn't the same plant when it's planted in the garden in spring - well, actually it is - but not the same root system.
They would be would be true to the "parent" plant and I'd have a head start on spring planting!
The experiment
Since I had nothing to lose if I tried, I took cuttings of my tomato plants before the first frost and stuck them in a jar of water.
Some varieties of tomato plants will root in water in about a week, others take a bit longer.
As the weeks go by, the roots kind of go crazy! After awhile you'll have a mat of roots in the water.
Tomato plants are heavy drinkers, so you'll need to keep an eye on the water level in the jars and top them off when the water gets a little low.
Since we have "rural water" here in Oklahoma, which is lake or municipal well water that is treated and piped to homes, I fill a glass of water and let it stand without a lid for at least 24 hours. Any chlorine dissipates in the air before I add the water to the plants' jars.
If you have well water you may not need to do this, but if you have city water I recommend that you let the chlorine evaporate.
Your cuttings will grow best in a sunny windowsill.
Spring update
That first fall, I took cuttings of the Bradley tomatoes I was growing before the first frost warning. Bradley is an heirloom variety.
I also took cuttings from the Early Girl plants, which are a hybrid variety.
Although I changed the water weekly, I think the cuttings would have also benefitted from some compost tea or other diluted liquid fertilizer during the winter months.
Early in January I lost the Bradley cuttings. I think they just ran out of energy and sustenance and they gave up.
However, the Early Girl plants did well all winter. At about the end of February their dark green leaves began to lighten. They probably needed some supplementing with fertilizer, since water doesn't have the nutrients that plants need, like soil does.
One of those cuttings grew really tall and even bloomed once. I pinched the flower off, not wanting the plant to put energy into producing fruit. Then I cut that plant in half and stuck the top half into another glass of water so that it too could root.
In the photo above, you can see that the Early Girl plants have turned light green from lack of nutrients.
How to pot up your tomato cuttings
My original idea was to cut the tops off of the original cuttings and let them root for additional plants, or to replace the original cuttings if necessary. But I changed my mind and potted up the rooted cuttings in February.
Plastic cups work well as pots, They are inexpensive and you can write on them with a Sharpie so you'll remember what varieties you're growing.
Use a sharp knife to cut a hole or two in the bottom of the cup.
Put an inch or so of potting soil in the bottom of the cup. You'll want to plant your cuttings deeply so don't use too much soil on the bottom.
Set the rooted cutting inside the cup and hold it in the center, while adding potting soil around the stem and roots. You can use a spoon to add the soil around the roots if you wish. Try to allow the roots to spread through the potting soil if you can.
When the cup is full, tamp the soil down a bit or compact it with your fingers, then add more to bring the level back up to the top.
The plants will grow new roots all along the buried stem.
Water the potted cuttings well and set the cups in the sink to drain. Remember that the plants have been living in water all winter, so they will need plenty of water while they adapt to their new environment.
But they also don't like having wet roots, so be sure the soil can drain easily.
If needed, transplant these plants into larger pots before spring.
You can plant your tomatoes in your garden after all danger of frost has passed in the spring.
Tomato plants won't survive a frost, so don't be in too much of a hurry to plant them out. Tomatoes don't really take off in the garden until the weather warms up anyway, so be patient.
Even though you can't plant them outside any earlier than seed-started transplants, you'll have larger plants when it's time.
Harden your plants off before planting in the ground by setting them outside on nice days in a protected spot. Bring them back inside at night.
Gradually increase the time they spend outside. Pinch off any flowers on your plants until they've been planted outside.
You now have good-sized transplants to set out in your garden.
Fragile seedlings are prone to fungus and attractive to cutworms, but you've passed that stage and have large, healthy transplants that a garden center would sell for a high price. Congratulations!
You should save tomato seeds too
Because I'm a cautious sort of person, and don't like putting all my eggs in one basket so to speak, I also save seeds from my tomato plants each summer.
I like a wide array of tomato varieties, and seeds for some of them can be hard to find. I like having a back-up plan so I take cuttings in the fall to keep over the winter, but I also save seeds to plant in spring.
Here's how to store seeds for the best germination, whether you're storing seeds from your own plants or a seed packet you purchased.
Keeping records
If you grow more than one variety of tomatoes and save cuttings from them all, keep a record of what varieties you're over-wintering. Even if you're only saving cuttings from one variety, keep records of when you took the cuttings and how they did over the winter.
Sharpie pens will write on glass jars and on plastic cups to help you keep track of which plants are which variety.
Here is some of the information you should record:
- Are you growing heirloom or hybrid varieties?
- Are they determinate or indeterminate plants? (Just FYI, I have not tried over-wintering determinate tomato plants.)
- What date did you take the cuttings?
Some varieties will grow from cuttings better than others, and the only way to find out which works best is to experiment and keep track of your results.
I kept notes each year, and shared the results (well, the first five years' worth of results) with you in this post: over-wintering tomato plants, successes and failures. Find out what I learned the hard way!
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