Overwintering tomatoes: this is how it works

The tomato plants, which are perennial in their homeland, can be overwintered with a lot of skill and a little luck. Here you can find out what to look out for when overwintering tomato plants.

As soon as the cold season approaches, many hobby gardeners ask themselves whether tomatoes can be overwintered. We get to the bottom of the topic and give you tips on how to overwinter tomato plants.

Are tomatoes perennial?

The tomato (Solanum lycopersicum) originally comes from South America and its bushy, wild relatives are also perennial in their warm home and are even relatively cold-tolerant. With our cultivated and bred tomato, however, things are a little different. It needs warmth extremely, is hardly tolerant of cold and grows elongated instead of bushy and woody. There are no hardy tomato varieties for our temperate latitudes and cold winters. Even temperatures below 10 °C damage the plants, cause leaves to die off and lead to deficiency symptoms such as purple coloring of the leaves due to a lack of phosphorus.

The right winter quarters for tomatoes should be as bright and warm as possible, and the plants should be completely healthy when they winter. It is not without reason that the sun-loving plants are usually sown anew every year: Tomato diseases such as these often take hold by the end of the season in October and November Late blight and late blight (Phytophthora infestans), the plants gone. Only completely healthy and well-nourished plants can be overwintered successfully. In addition, the choice of variety is crucial when overwintering tomatoes. Small, determinate tomatoes and wild tomatoes can be wintered well as a whole plant. When moving into the winter quarters, about half of the plant has to be cut back in order to adapt evaporation and light requirements to the dark season. But don't worry: numerous new side shoots form throughout the winter, which in turn will bear flowers and fruit next summer.

High-growing stake tomatoes cannot be overwintered as a whole plant, cuttings from the shoot tips are recommended for them. Overwintering tomatoes is more complex than sowing them again - but if the lighting conditions, water supply and temperature are right, it can still be successful.

Summary: Can you overwinter tomatoes?

• Tomatoes are generally perennial and can be overwintered.
• The prerequisite is that the plants are absolutely healthy.
• Overwintering is only successful in warm, very bright locations and with suitable varieties or by using cuttings.
• Tomatoes can form flowers during the winter, but these should be removed because the fruits cost the plant too much energy.

Tip: Why can't you harvest tomatoes in winter?

Tomatoes are produced for our supermarkets all year round in warm locations in high-tech, heated greenhouses with powerful additional lighting. In fact, tomatoes do not hibernate – given the right conditions, they continue to bloom and bear fruit. However, production is only worthwhile in warm countries with mild winters, because there the temperature difference to the outside air is lower. Under normal "living conditions" in cold Germany, good growing conditions for tomatoes are difficult to achieve - or waste a disproportionately large amount of energy.

Overwinter the tomatoes in the pot 

If tomatoes are to be overwintered successfully, we recommend using more robust wild tomatoes such as Humboldt tomatoes (Solanum humboldtii) or currant tomatoes (Solanum pimpinellifolium). Even the bush tomatoes, which are already highly branched, small in stature and determinate, such as ˈTiny Timˈ or ˈVilmaˈ are suitable for this. In order to overwinter whole plants in the pot, they should have been cultivated in the pot beforehand - the plants will not survive being transplanted from the bed into a pot. Wild tomatoes can be cut back by half before overwintering because they branch very well again next spring and also carry plenty of fruit on the many side shoots Fruit. You should not cut bush tomatoes at all before winter.

The pots with the tomato plants should be placed in the brightest possible place at 15 to 20 °C from the middle to the end of October. To overwinter tomato plants, they must be well-fed and healthy. A final fertilization in August and September before the transfer to the winter quarters ensures a good nutrient balance. Only very bright locations are suitable, such as conservatories. A mirror can be placed behind the plants on south-facing windows to improve the light supply. Heated greenhouses are optimal, because the light yield is maximum here - unfortunately the energy requirement is extremely high, which is why they are not recommended.

Overwintered tomato plant forms long shoots: what to do?

The plant tries to compensate for the reduced light supply by wilting and forming many side shoots. These bright shoots should therefore not be removed. However, you should check them regularly for pests as they are prone to them.
However, if extremely light, thin and unstable shoots form, this is a sign that the light supply is not sufficient. So another location should be found or additional exposure should be provided. Looking for a lighter spot is of course always the cheapest and most sustainable option. Special plant lamps are suitable for the exposure, which, in contrast to normal lamps, offer a light spectrum tailored to plants. However, this type of hibernation is not very sustainable, even if LEDs can be used.

Overwintering cuttings, which we present below, requires less energy. During the winter until planting out in the following May, watering should be done sparingly in winter and regularly again from March. You should start fertilizing again in the spring.

tip: Watch out for possible pest or disease infestations throughout the winter period, but especially from February and March. Pests should be combated as quickly and efficiently as possible and infected plant parts or entire plants should be disposed of quickly.

Tomato cuttings overwinter

A good and space-saving alternative to overwintering whole tomato plants is the production of offshoots. Tomato cuttings are easier to overwinter: They are smaller, so they are more likely to be satisfied with a window seat and, if in doubt, only need a small lamp. To do this, only cut off shoot tips that are about 10 to 15 centimeters long from healthy and well-nourished plants and leave them in the water or in moist growing substrate, like ours Plantura Organic Herb & Seed Soil, root at about 20 °C. After about a week, the first new roots appear and after being transferred to more nutrient-rich potting soil, the cuttings usually grow quickly. So that the plants do not grow too much, the nutrient supply should be provided by a slowly flowing organic fertilizer such as ours Plantura organic tomato fertilizer respectively. Overall, you should only fertilize sparingly in winter.

Of course, tomato offshoots must also be checked regularly for pests. From mid-May, the plants can go outside again, where they bear fruit particularly early due to their growth advantage.

This is much easier than with tomatoes Overwintering Physalis. The edible lantern flower can survive the cold season in the winter quarters and bear fruit early the following year.