Like any other crop, the tomato has its own preferences for temperature readings. They are different during different periods of life. If you understand these features, it is possible to help the crop at a particular stage of development, as well as affect the size and quality of the crop (or, at least, not to harm it). It is easier to use this information in a heated greenhouse. However, some knowledge will help us, dacha owners and gardeners, when growing seedlings, determining the time of their planting in the ground and further care of tomatoes.
- Tomato seed germination
- Tomato seedlings
- From seedlings to budding
- Tomato budding and flowering period
- Common optimum temperatures for tomato development
- How to influence temperature changes on tomato?
Tomato seed germination
It needs +10°C for tomato seeds to germinate. But if you raise it to +20...+25°C, the seedlings will already appear on the 3rd-4th day.
First few days (2-3 days), tomato seedlings need +10...+15°C. This temperature regime protects them from pulling and allows the faster development of the root system, which is very important for this crop, as it has a small supply of nutrients in the seed.
From seedlings to budding
Thereafter, the most optimal conditions for the development of tomato seedlings is a combination of high light with daytime temperatures around +20 ... +25°C and its decrease at night to +9 ... +12°C. A sharp drop in temperature is inadmissible because it provokes stress and, as a consequence, a delay in plant development, changing the color of leaves to yellow with anthocyanin or bluish tint. © pt.depositphotos
Tomato budding and flowering period
Temperature conditions during this period are optimal in the range of +20 ... +25°C. Sharp fluctuations of temperature have a negative effect on bud formation and may cause their fall.
Elevation of temperature below +13°C in the nighttime causes deformation of anthers and decrease the quality of tomato pollen. At thermometer's readings higher than +30 ... +34°C the pollen grains lose their viability.
Deteriorates the quality of pollen and poor light, but this is compensated by increase of its mass.
General optimum temperatures for tomato
About the optimum regime for growth, development and fruiting of tomato is considered the temperature regime in the range of +20 ... +25°C in combination with high light. With low lightness and cloudy weather, the temperature range is +15 ... +18°C during the daytime and +10 ... +12°C at night.
Higher temperatures to +30 ... +31°C combined with low humidity, which is annually observed in southern regions, inhibit the photosynthesis process of culture, and thus the plant development processes. Temperatures over +35°C cause plants to starve and die.
The lower temperature threshold for southern tomato varieties is -1°C, for northern ones -3 ... -4°C with no wind. It is worth mentioning that northern varieties grow and develop in a slightly wider temperature range of +8 ... +30°C, southern ones +10 ... +25°C.
The lowest threshold for soil temperature, contributing to valuable work of tomato root system is equated to +14°C. Optimum soil temperature for complete vegetation of seedlings is +23...+25°C, for adult plants - +18...+22°C.
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How to influence temperature changes on tomatoes?
It is clear that it is possible to form optimal temperature conditions for tomato only in heated greenhouses. But it is not difficult to judge from these figures that both for the open air and for the balcony cultivation as well as for the cultivation in non-heated hothouses some secrets may be applied.
Wishing to shorten the terms of tomato sprouting it is necessary to bring up the temperature to +20 ... +25°C.
To prevent pulling of tomato seedlings immediately after sprouting it is possible to lower the temperature for 2-3 days to +10 ... +15°C.
When hardening tomato sprouts before planting in the ground you must not allow sharp temperature variations because it causes stress to the plants and provokes braking of their development.
Perfect hardening of tomatoes ensures their resistance to a short-term drop in temperature to 0°C.
Being planted in an unheated greenhouse or under a film, it is possible to accelerate production. However, remember that when the temperature in a film greenhouse rises above +30°C combined with high humidity, tomato fertilization does not occur, the color falls off, the fruits, if formed, are few, they are small, hollow. After such stress, normal (productive) pollen is formed only in 10-14 days.
When planting tomatoes in the open ground it is necessary to consider the optimal time for the area. Delayed planting, even for 10 days, already greatly reduces the yield.
Summer in the southern regions, to somewhat reduce the temperature and keep humidity in the area of tomato bushes, you can install shading - masking grid, or resort to double row placement of the crop, which provides mutual lateral shading of rows, which is also a prevention of fruit burns occurring at temperatures above +34°C.
Mulching tomatoes not only preserves moisture in the root zone of the soil, but also somewhat reduces its temperature, which has a good effect on the metabolic processes of plants.
It is not just high or low temperatures that are important for tomato, but also the nature of their fluctuation. If you keep plants at high temperatures all the time, the substances necessary for growth and development, formed by them during the day, are spent at night on breathing. This slows down their development and ultimately affects yields. When temperatures fluctuate with a decrease in the evening time, the process of flowering, setting, and then maturing of tomatoes is accelerated.