Who doesn’t love them, the sun-ripened, aromatic organic tomatoes from their own garden? In order for your own cultivation to be successful, the right temperatures are very important, because tomatoes are very sensitive to cold.
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tomatoes and temperature
The tomato plants (Solanum lycopersicum) originally come to us from the warm regions of South and Central America. They love it warm and sunny and cannot cope with the winter cold at all. Especially on our European nights, however, the temperatures drop quite sharply in spring and autumn – and sometimes even in summer. This can quickly pose a threat to your tomato plants. Because the plants can hardly tolerate temperatures below 15 degrees Celsius, even at night. The plants usually do not survive below 13 degrees or suffer damage. The ideal tomato temperature is between 18 and 25 degrees Celsius.
If your tomato plants have gotten too cold, the plant’s metabolism will no longer function properly. The formation of sugar and starch is impaired and there is a lack of energy. Depending on the current plant status, the following damage can then occur:
- no (complete) pollen pollination possible
- Fruits become too small, hard and seedless
- Tearing open the tomato fruit
- curling of the leaves
- Growth depression with shortened leaf spacing
- little to no flowering
- discoloration of the leaves
- dying of the leaves
Especially in spring and autumn there can be individual phases with ground frost at night. It is then particularly important that you protect your tomato plants from the frost. Cover the bed with garden fleece or protect the plants with a foil tunnel. Tomato hoods for individual plants are also commercially available.
ripening of the fruit
When it starts to get cold at night in autumn and frost is imminent, you can remove the still green tomatoes from your bushes and let them ripen indoors. This prevents the fruits from being damaged and you can still enjoy them. They ripen red within a few days. Storage in newspaper at 18 to 20 degrees Celsius is ideal.
frequently asked Questions
If your tomato plant got frost during the night, you can try to save it. This is easier to do with potted tomatoes than with free-range tomatoes. To do this, bring the tubs into a warm indoor space. Water the plant with warm water and place it on a bright, sunny window sill. If you put a glass container over the perennial, you also create a slight greenhouse effect.
While the tomato plants grow for several years in the warm countries of origin due to the mild winters, overwintering is almost impossible in our latitudes. Tomato plants in pots or tubs cannot survive the cold winter either. The cold makes them susceptible to pests and diseases. The lack of sunlight causes them additional problems. Even if, contrary to expectations, it should be possible to get the plant through the winter, it is often very weak and vulnerable afterwards.
The optimal temperature for the tomatoes is between 18 and 25 degrees Celsius. While low temperatures can cause problems from as little as 15 degrees Celsius, higher degrees are hardly a problem in our climate range. The upper limit is around 45 degrees Celsius. Only then does heat damage occur in plants and fruits.