For most hobby gardeners it is clear that tomatoes are annual plants. Planted, harvested and disposed of – this is the classic history of most tomatoes. However, with a little skill, the plants are perennial and can overwinter without any problems.One thing is clear, tomato plants are not hardy. They don’t survive the cold season outdoors. Where the tomato usually comes from (Central America, South America), temperatures do not fall below 15 degrees even in winter.
Tomatoes grow there perennial and prove to be very easy-care, tolerant plants. In this country it is above all the lack of light and the cold outside that make wintering impossible.
It depends on the choice of variety
When it comes to overwintering a tomato, choosing the variety is crucial. Beefsteak tomatoes, for example, are completely unsuitable because the energy consumption required for lighting would stand in the way of the harvest result.
The situation is completely different with wild tomatoes, even dwarf tomatoes can overwinter wonderfully. There are several varieties in which there is no excess energy consumption, but the tomatoes can still overwinter. This includes:
- red marbles
- Bolivian fruit tomatoes
The following varieties of dwarf tomatoes are particularly suitable for overwintering:
- Tiny Tim
- Red Robin
- Micro Tom
What distinguishes the tomato varieties?
The red marble is a wild tomato from the Andes that is extremely vigorous. It withstands the hardships of the cold season well and produces lots of red tomatoes with an average diameter of 1.5 cm during harvest time. The mild aroma is just right for all tomato lovers.
In terms of growth strength, the Humboldtii is in no way inferior to the red marble, it is also extremely robust and healthy. She invests her existing energy in the production of cherry-sized tomatoes. As long as it is not subjected to long-term frost, the Humboldtii does well with the reduced heat and low levels of light during the winter period.
Bolivian fruit tomatoes
This tomato variety is the most cold-resistant variety. It bears its small fruits, which grow on fan-like shoots, until the first frost. Tomato lovers will have a dependable plant for years of enjoyment when they buy this variety.
With a maximum growth height of 30 cm. the Tiny Tim is particularly suitable for cultivation in pots. Harvest time is in late summer until autumn. The small cherry tomatoes are very aromatic and can bloom for several years in a row.
The Red Robin is a bush tomato that is very popular with hobby gardeners. The dwarf tomato can even be grown on the windowsill, it provides delicious cocktail tomatoes. With a growth height of 30 cm. winter quarters are easy to find and nothing stands in the way of perennial cultivation.
Who 30 cm. still too big, you can finally harvest crunchy fruit with this mini tomato, which grows to a height of just 12 cm. If it is overwintered properly, the plant is perennial and delights every year with a small but fine fruit selection.
Overwintering tomatoes: Here’s how!
Even if most tomatoes can survive temperatures of up to 0 degrees Celsius for a short time, such a cold spell weakens them. In order to carry out the wintering successfully, it is necessary to give the plant timely. It is not the daytime temperatures that should be observed here, but the values at night.
Starting signal: time to clear up is when the thermometer shows a low temperature of 12 degrees at night.
Tomatoes overwinter on the windowsill
There are some conditions that the tomato plant can optimally overwinter on the windowsill. They desperately need winter dormancy due to a combination of cool temperature but plenty of light giving the plant everything it needs. That’s how it works:
- remove half of all shoots before the transition to winter quarters
- remove the withered foliage completely
- move the pot to a bright place
- keep temperatures between 10 and 12 degrees
- do not fertilize from early October to mid-March
- water lightly to keep the substrate slightly moist
A bright south-facing window sill is ideal in a room with a low temperature. Darkness, on the other hand, is not suitable at all, so winter quarters in the basement are unsuitable.
The greenhouse as quarters in winter
A sun-drenched greenhouse or a conservatory are ideal for bringing tomato plants through the winter. Depending on the willingness to put in effort, it is even possible for wild and dwarf tomatoes to overwinter and produce fresh tomatoes at the same time. How to do it:
- only move vital plants into the quarters in autumn
- look for a sunny spot in the conservatory
- temperatures should be between 16 and 22 degrees
- water whenever the soil surface dries
- fertilize with potassium, but only half the concentration
- pollinate manually by shaking the shoots
The problem with the lack of light
Due to cloudy winter weather, there is a lack of light both in the greenhouse and on the windowsill. The higher the outside temperatures, the more light is needed. If you spend the winter in a cool place, 1,500 lux is the minimum.
As soon as the temperatures are 15 degrees or more, a requirement of 2,000 lux or 3,000 lux is expected. The following methods can be used to prevent the lack of light:
- mount a mirror behind the tomato plant on the windowsill
- install a plant lamp
- place the special lamp a maximum of 80 cm above the tomato plant
- illuminate around eight hours a day when there is no daylight
With an inexpensive lux meter, the lux value at the place of winter storage can be easily determined. However, you must not forget that the need for fertilizer and water also increases with exposure to light.
In this country, the one-year cultivation of tomato plants is only justified by the fact that they are sensitive to frost. For most home gardeners, it is easier to discard and replant the plants once a year. In South America and the regions there is no lack of light, so that the tomato plants are generally cared for perennial.