Temperature regime for tomato seedlings 

Experienced farmers know that for successful growth, tomato seedlings require not only regular watering and fertilizing, but also the presence of a favorable temperature regime. Depending on the stage of development, the recommended temperature for tomato seedlings is different. So, for example, using this adjustable indicator, you can harden tomatoes, speed up or slow down their growth, and prepare for planting in open ground. In this article, you can find out detailed information about which temperatures are best for tomato seedlings and how you can adjust their values.

seed Processing

Even before sowing tomato seeds in the ground, you can use the effect of temperature on the crop. So, many gardeners warm up and harden the seeds of tomatoes before sowing. Heated seeds germinate quickly and evenly, forming strong, healthy sprouts. In addition, it has been noticed that when using heated seeds, the yield of tomatoes increases significantly.

Tomato seeds can be heated in several ways:

• In winter, regardless of when it is planned to sow seeds in the soil, they can be heated with heat from a heating battery. To do this, tomato seeds should be collected in a cotton bag and hung near a heat source for 1,5-2 months. This method does not create much trouble and effectively warms up the tomato seeds.
• Tomato seeds can be heated with an ordinary table lamp. To do this, put a piece of paper on the ceiling turned up, and tomato seeds on it. The whole structure must be covered with a paper cap and left to warm up for 3 hours.
• You can warm up the tomato seeds in the oven by laying them on a baking sheet, which is placed in the oven, heated to 60⁰C. Such heating should last at least 3 hours, provided that the temperature is stable and stirred regularly.
• Immediately before germination, you can warm the tomato seeds with warm water. For this, tomato seeds must be wrapped in a rag bag and lowered into water heated to 60⁰From 3 o’clock. The temperature of the water can be adjusted by periodically adding boiling water.
• Long-term heating is carried out by the method of variable temperatures: 2 days of tomato grain must be kept at a temperature of +30⁰C, then three days in conditions with a temperature of +50⁰C and four days with temperatures up to +70-+80⁰C. It is necessary to increase the temperature during prolonged heating gradually. It is worth noting that this method gives the gardener a lot of trouble, but it is highly effective. Plants grown from seeds heated in this way are highly resistant to drought.

It is recommended to warm up the seeds of your own harvest and purchased in sales networks. This procedure improves the sowing qualities of tomatoes and stimulates earlier fruiting.

Low temperatures can also be used to prepare tomato seeds for sowing seedlings. So, hardening of seeds makes tomatoes highly resistant to cold, endows plants with increased vitality. Seeds that have undergone hardening quickly and evenly sprout and allow seedlings to be planted in the ground earlier than without undergoing such heat treatment.

For hardening, tomato seeds should be placed in a humid environment, for example, wrapped in a wet piece of cloth, and then in a plastic bag that will not allow the liquid to evaporate. The resulting bundle must be placed in a refrigerator, the temperature in the chamber of which is -1-0⁰C. At such a low temperature, the seeds must be kept for 12 hours, after which they must be placed in conditions with a temperature of +15-+20⁰C also at 12 o’clock. The above method of hardening with variable temperatures should be continued for 10-15 days. Seeds may sprout during hardening. In this case, their stay in conditions with elevated temperature should be reduced by 3-4 hours. In the video below, you can also find useful information about hardening tomato seeds:

It is worth noting that biological products, growth stimulants, nutrient or disinfectant solutions, such as ash decoction or a weak solution of potassium permanganate, can be used to harden tomato seeds during moistening.

temperature for germination

It is recommended to sow in the ground for seedlings only germinated tomato seeds. So, seed germination can begin already during hardening, otherwise tomato seeds should be additionally placed in humid conditions with elevated temperatures.

The optimum temperature for tomato seed germination is +25-+30⁰C. Such a warm place can be found in the kitchen near the gas stove, on the windowsill above the heated battery or in the pocket of underwear. So, for example, some representatives of the fair sex claim that by placing a bag of seeds in a bra, the germination of tomato seeds occurs very quickly.

After sowing

Germinated tomato seeds can be sown in the ground for seedlings, but it is also necessary to carefully control the existing temperature regime. So, it is especially important at the initial stage to place crops in a warm place in order to get seedlings as quickly as possible. That is why, after sowing and watering, pots with crops are covered with a protective film or glass, placed on a surface with a temperature of + 23- + 25⁰C.

After germination, not only temperature is important for seedlings, but also lighting, so it is better to place containers with tomatoes on windowsills on the south side or under artificial lighting lamps. The temperature when growing seedlings of tomatoes should be at the level of + 20- + 22⁰C. This indicator will ensure uniform, healthy plant growth. If the room temperature deviates significantly from the recommended parameter, then you may encounter the following troubles:

• At a temperature of +25-+30⁰With the stems of seedlings stretching excessively upwards, the stem of the plant becomes thin and brittle. The leaves of tomatoes may begin to turn yellow, which eventually leads to their fall.
• Temperature below +16⁰C does not allow the green mass of tomatoes to grow evenly, slowing down its growth. However, it should be noted that at temperatures of +14-+16⁰The root system of tomatoes is actively developing.
• At temperatures below +10⁰With the development of seedlings and its root system, it stops, and the temperature is below +5⁰C leads to the death of the plant as a whole. Therefore +10⁰C is considered the minimum temperature for tomato seedlings.

Given such an ambiguous effect of temperatures on the growth of tomato seedlings, some experienced farmers recommend maintaining a temperature of + 20- + 22 in the daytime⁰C, and at night lower it to indicators equal to + 14- + 16⁰C. Such an alternation of slightly lower and higher temperatures will allow the green mass and the root system of tomatoes to develop harmoniously at the same time. Seedlings in this case will be strong, strong, moderately tall.

When observing temperatures, it is worth paying attention not only to the air temperature directly near the growing tomatoes, but also to the soil temperature. So, the optimum soil temperature is + 16- + 20⁰C. With this indicator, the root system safely absorbs nitrogen and phosphorus from the soil. At temperatures below +16⁰Since the roots of tomato seedlings shrink and cease to absorb moisture and nutrients in sufficient quantities.

Many gardeners sow tomato seeds in a single container and, with the appearance of several true leaves, dive tomatoes into separate containers. During transplantation, plant roots are damaged and stressed. That is why for a few days before and after picking, it is recommended to place tomato seedlings in conditions with a temperature of + 16- + 18⁰C. It is possible to regulate microclimatic conditions in an enclosed space by opening the vents, but drafts, which can destroy seedlings, must be excluded.

Planting time

It is time to prepare the grown seedlings with 5-6 true leaves for planting on a “permanent place of residence” by hardening. You need to start the preparation procedure 2 weeks before the intended landing. For this, tomato seedlings are taken out into the street: first for 30 minutes, then gradually increasing the time spent on the street until full daylight hours. When hardening, tomato seedlings adapt to the temperature, humidity and light conditions of open ground. For more information on hardening tomato seedlings, see the video:

Tomatoes should be planted in open ground no earlier than the end of May – the beginning of June, when the threat of low temperatures has passed. At the same time, very high daytime temperatures can also negatively affect the survival rate of dived tomatoes. So the temperature is below 0⁰C is capable of completely destroying the plant in a few minutes. The upper temperature limit for planted tomato seedlings should not exceed +30⁰C, however, adult tomatoes are able to tolerate temperatures up to +40⁰C.

Greenhouse conditions are more adapted for growing tomatoes. When planting seedlings there, you can not worry about night frosts, however, daytime temperatures should be controlled. In a closed greenhouse, microclimate indicators may exceed the upper temperature limit. To reduce the temperature, the greenhouse should be ventilated without creating a draft.

You can also save tomatoes from the heat in the greenhouse by spraying. To do this, prepare a solution of urea: 1 tablespoon per 10 liters of water. It is worth noting that such spraying will not only protect tomatoes from combustion, but will also become a source of essential trace elements.

Heat protection

Prolonged exhausting heat deprives tomatoes of vitality, dries out the soil and slows down the development of the root system of plants. Sometimes a hot summer can even be fatal for tomatoes, so gardeners offer some ways to protect plants from heat:

• You can create an artificial shelter for tomatoes using spunbond. This material passes air and moisture well, allows plants to breathe, but at the same time does not let direct sunlight through, which can burn tomato leaves.
• You can prevent the soil from drying out by mulching. To do this, cut grass or sawdust must be placed in a thick layer (4-5 cm) near the trunk of tomatoes. It is worth noting that mulching also protects the soil from overheating and promotes natural irrigation in the morning through the penetration of dew.
• Along the perimeter of growing tomatoes, you can create a natural screen of tall plants (corn, grapes). Such plants will create shading and become additional protection against drafts.

The use of the above methods for protecting tomatoes from heat is especially relevant for open ground conditions during the flowering of plants and the formation of ovaries, since the heat is over +30⁰C can significantly damage plants, which is why they “throw off” the flowers and the resulting fruits. Such exposure to high temperatures significantly reduces crop yields.

Rescue from frost

With the advent of spring, I want to quickly try the fruits of my labors, which is why gardeners try to plant tomato seedlings in greenhouses, greenhouses, and sometimes in open ground as soon as possible. However, even at the end of May, unforeseen frosts can strike that can destroy young tomatoes. At the same time, by monitoring the weather forecast, foreseeing serious cold snaps, negative consequences can be prevented. So, temporary film shelter on arcs will help save seedlings in the open field. Cut up plastic bottles or large glass jars can be used as insulated, separate shelters for seedlings. In case of short frosts with relatively low humidity, paper caps can be used, the lower edges of which must be hermetically sprinkled with soil.

During frosts, the best protection for tomatoes is shelter, as it will allow you to keep the heat given off by the soil. So, low greenhouses are really able to prevent freezing of tomato seedlings even at a temperature of -5⁰C. Greenhouses, on the other hand, have rather high walls with a large area, due to which the air cools very quickly. Additional protection for tomatoes in unheated greenhouses can be the paper caps or rags described above. So, some owners cover the greenhouse with old rugs or old clothes during frosts. This measure allows you to increase the coefficient of thermal insulation.

In central Our Country, only in mid-June can we say that the threat of frost has completely passed. Until that time, every gardener should carefully monitor the weather forecast and, if necessary, provide for a measure to protect tomato seedlings from low temperatures.

Tomatoes are the indigenous inhabitants of South America, so it is quite difficult to grow them in domestic climatic latitudes. The farmer tries to compensate for the discrepancy between natural humidity and temperature by additional heat treatment of the seed, the creation of artificial shelters, wind barriers, and other methods. The tomato reacts very actively to temperature changes, so the regulation of this indicator allows not only to maintain the viability of tomatoes, but also to accelerate, slow down their growth, and increase the volume of fruiting. That is why we can safely say that temperature is a tool that should always be in the capable hands of a master gardener.