How often should tomatoes be watered in open ground?

Tomatoes grown outdoors won't survive without regular watering. Tomatoes struggle with the lack of moisture that comes with watering. Metabolic and physiological processes within the plant slow down or even stop altogether.

Lack of sufficient water causes tomato ovaries to fall off, while excessive waterlogging provokes fungal diseases.

Why is irrigation necessary?

Tomatoes are 80% water, the fruit 94%, and the remaining 20%, with 6% of the fruit being dry matter, which is what makes up the body of the plant: roots, stems, and leaves. Water is essential for the metabolic processes occurring within the seedlings.

1. Transpiration is the process of water movement within a plant, from the roots to all its organs, and its evaporation from the outer parts, primarily the leaves. By moving with the water, nutrients are freely distributed to all plant cells. This process is also responsible for thermoregulation, protecting tomato plants from overheating and the breakdown of proteins caused by heat.
2. Chemical reactions convert nutrients and microelements into energy and enzymes necessary for tomato growth and development. Such processes can only occur in aqueous solutions.
3. Photosynthesis is the process by which sunlight energy is converted into the energy of chemical bonds within organic cells. Simply put, photosynthesis reactions release oxygen and glucose molecules from water, which are essential for plant life.

Without sufficient moisture, healthy and vigorous tomato plants become stunted and wilt. Weakened plants expend their remaining energy solely on maintaining their roots, while stems, leaves, and fruit buds dry up and fall off. Watering restores this lost energy and brings tomato plants back to life.

Watering time

Tomatoes need watering throughout the entire growing season. From sowing the seeds until the fruits are fully ripe, the plants need water. The only exception to this rule are periods of prolonged, heavy rainfall.

The optimal time to water tomatoes is 1-2 hours before sunset. The soil surface should be slightly dry by the time the night cools, so the leaves and stems don't become overcooled by cold vapor. Watering in the early morning hours, when it's not too hot, is also possible. If the sun is at its zenith, the damp soil surface will quickly turn into a dense, hard, air-impermeable crust.

Watering during growth and fruiting

The growing season of tomatoes is divided into several stages:

1. Development and growth of seedlings.
2. Adaptation to a new location after planting in open ground or in a greenhouse.
3. Growth and development before flowering.
4. Bloom.
5. Formation of fruit ovaries.
6. Fruiting.

Tomatoes require watering at each stage of growth, but the amount and frequency of water vary at each stage:

• After planting tomato seedlings in open ground and watering them for the first time, you should take a significant break of 10-14 days to allow the tomatoes to get used to the new conditions without disturbing their natural course;
• Watering should be resumed when it becomes noticeable that the plant has taken root and started to grow; at this time and until flowering, tomatoes are watered frequently (see the section “Watering regime” below);
• with the beginning of flowering, watering is done less frequently, but the amount of water is increased;
• during fruit setting, the volume of water is increased even more with each watering, the frequency is the same as during flowering;
• When the tomato fruits begin to fill out and turn slightly brown, the number of waterings is reduced, the amount of water is reduced, and this regime is maintained throughout the entire fruiting period.

Regulating the frequency and volume of watering is essential to maintain the plant's water balance. During active growth, tomatoes absorb significantly more water to build foliage and form stems. Moderate watering during the fruiting period is necessary to prevent the tomatoes from cracking and to preserve more nutrients.

Watering rules

When watering tomatoes in open ground, it is necessary to follow certain rules:

1. Tomato seedlings do not tolerate surface watering well; water evaporates quickly from the leaves and does not reach the main source of moisture—the roots. Therefore, it is better to water the bushes at the roots.
2. After each watering, the soil should be lightly loosened and the surface of the earth sprinkled with mulch - a thin layer of peat or dry compost.
3. Before watering tomatoes, tap water should be left to stand for at least 24 hours to allow harmful impurities to evaporate.
4. When watering, consider the specific tomato variety's requirements. Taller tomato plants require more water than their shorter counterparts. Early-ripening varieties require more frequent watering; they develop faster, which requires water.

Rules always imply exceptions, so gardeners, when growing tomatoes in their plots, rely on actual conditions: climate, soil composition and fertility, and the presence or absence of water sources. Different conditions force gardeners to adjust some basic rules.

Natural bodies of water where gardeners get water for their tomatoes (rivers, ponds, and lakes) contain substances harmful to plants, including fungal spores, viral cells, and harmful microorganisms. An additional rule when using such water is purification. Purification can be accomplished in various ways:

• chemical treatment with chlorine-containing preparations;
• use of folk remedies for water purification: iodine, potassium permanganate, soda ash, ash;
• use of modern cleaning systems.

Rainwater is very useful for watering plants; tomato plants revive after a rain, replenish their energy, and are ready for further development. Collecting rainwater for watering tomatoes is another additional rule that is advisable to follow every time there is precipitation.

Water quality

The water temperature for watering tomatoes should be between 23 and 27°C. This can be achieved by placing the reservoir in a sunny spot or placing it in a greenhouse. Watering tomatoes with cold tap water is not recommended for the following reasons:

• a sharp drop in temperature will cause the fruit ovaries to drop and their formation to stop;
• Tap water contains chemical compounds that are harmful to plants: chlorine, heavy metal molecules.

You can speed up the heating of water for tomato plants by using dark-painted barrels as reservoirs. This paint absorbs sunlight well, and the water warms up quickly. The cool night air will cool the water, but by the time you're ready to water, it will be warm enough for use.

Consumption rates

The amount of water needed for tomato irrigation varies at different stages of the growing season. Gardeners who have been growing tomatoes for many years find their own optimal amounts based on the variety, growing technique, and weather (climatic) conditions. We have included some average data in the table in the next section.

Watering mode

Growing tomatoes in open beds is more challenging than in a greenhouse. Many weather-related factors influence tomato growth, including rain, cold air, strong winds, and heat. All these nuances must be taken into account when watering tomato plants.

Our recommendations are not a panacea for all situations, especially unexpected ones. Experienced gardeners, having followed our advice, apply them with consideration for weather changes, adjusting the amount of watering and water usage based on specific circumstances.

Drip irrigation

The introduction of modern technologies into crop production has significantly reduced labor costs and resource consumption. One such innovation is the use of drip irrigation systems. Landowners successfully use this irrigation system to water fruit and vegetable crops, flower beds, and lawns.

Automated drip irrigation systems installed in vegetable gardens and greenhouses save time, water, and reduce labor. Experienced gardeners install their own homemade systems in their beds. While these systems may be far from perfect, they still perform their intended functions well.

Drip irrigation for tomatoes is a method of watering the plant where water is applied only to the roots and moistens the soil at the base of the main stem. This method allows for the adjustment of the water amount and intensity, fully satisfying the agronomic requirements of tomatoes.

The system can also be used to fertilize tomatoes by adding the necessary fertilizer to the reservoirs. This fertilizer is delivered directly to the tomato roots and is not wasted through moisture evaporation from the leaves and soil surface.

Conclusion

The quantity and quality of watering when growing tomatoes outdoors are important aspects that shouldn't be overlooked. Plants, like people, cannot survive and thrive without water. Fruit yield and flavor largely depend on how much, when, and in what quantity the seedlings receive the necessary moisture. Your tomato plants, regardless of variety or ripening time, will always respond well to care and attention.