Tomato plants (Solanum Lycopersicum) thrive in warm and sunny weather, but too much heat and little moisture can cause the plants to become stressed and die.
Because they may send out long roots to get moisture buried deep in the soil, potted tomatoes are especially prone to dryness. However, during a heatwave, watering tomatoes in pots properly and conserving moisture boosts your tomato plant’s chances of survival and eventual fruit output.
Summer heat can bring your tomato plants to a standstill, even if they were previously productive. When temperatures reach 85°F to 90°F during the day and 75°F at night, tomato flowers sometimes fail to pollinate and drop, halting new fruit development.
The longer the heat continues, the longer those tomato blooms will go on hold and do nothing; thus, hot weather can cause your tomato crop to be delayed.
In our guide, you can learn more about watering tomatoes in hot weather with the right watering techniques. By the end, you’ll know what to do when there is too much sun and what temperature is too hot for tomato plants.
How Often Should You Water Tomato Plants In 90-Degree weather?
Several factors influence the frequency with which tomatoes require water during a heatwave. The time it takes for the pot to dry depends on the size of the container, the type of soil, and the amount of drainage. Feeling the soil once a day during warm weather is a valuable indicator for assessing water needs. (Read Tomato Hornworm Life Cycle)
Wilting, failure to fruit, bloom drop, or green fruits refusing to ripen further are signs of water and heat stress. New flowers and ripening will develop naturally when daytime temperatures fall below 95 degrees Fahrenheit, but you may avoid wilting and plant damage by keeping the soil moist. Allowing the soil to dry out and the tomato to wilt can cause the plant to die or the fruits to crack.
Blossom end rot, in which the tomato’s blossom end blackens and rots, can also happen if the soil isn’t kept evenly moist. Although potted tomatoes require more regular watering during a heatwave, avoid overwatering, which can weaken or kill the plant by resulting in muddy, waterlogged soil.
Feel the soil at least twice a day, in the morning and afternoon, when it’s hot and dry, and water as needed. According to experts, tomatoes grown in pots should never be allowed to dry up. The tomatoes require water if the soil feels dry at a depth of one inch. Many plants may require twice-daily watering during a heatwave to keep the soil from drying up.
Pouring water directly onto the soil is the best technique to water tomatoes as watering from above wets the foliage, and the water evaporates before reaching the soil. It is easy to water with a watering can or hose set to a slow stream to soak deeply into the soil.
Continue watering tomatoes in pots until the excess drips out of the bottom drainage holes on the pot, which shows the moisture has penetrated deeply.
Should You Water Tomato Plants In The Heat Of The Day?
Growing potted tomato plants differs from in-ground gardening. First, remember that pots cannot retain moisture like in-ground gardens, so you need water more often.
No growing tomato plants or any other types of plants should be watered in the hottest parts of the day, even if you plant tomatoes in the early afternoon sun. It leads to scorching of the leaves if you carry out overhead watering, and the water evaporates before it reaches the plants’ roots.
However, there are other things to consider if you live in such areas with such high temperatures and want to grow tomato fruit successfully.
Pick the right variety
Summer Set and Phoenix are heat-tolerant tomato varieties that bear fruit production in high temperatures. Tomatoes with heat-related terms or locales in their names are typically labeled as “heat-set.”
Another option is to plant determinate kinds, whose fruit ripens all at once earlier in the growing season—before the major heat arrives. (Read Tomato Plant Leaves Turning White – What to do)
Pick the right spot
Tomatoes require full sun, which works well in the Midwest, Northeast, and Pacific Northwest. However, tomatoes grow best in areas with morning sun followed by filtered sun or light shade during the day.
In regions without natural shade, such as Southern California, the Deep South, Texas, and the Desert Southwest, build your shade when summer afternoons are scorching, and your tomatoes only receive morning sun when plants begin photosynthesis.
In areas such as Texas, Oklahoma, Florida, Southern California, and the Desert Southwest, you’ll find gardeners using shade cloth to cool tomatoes and retain soil moisture during the vital hours for pollination (usually between 10 AM and 2 PM).
The best yields come from a shade structure, which is open to the east with no cloth; thus, plants receive morning sun and avoid the scorching afternoon sun.
Use “50 percent” shade fabric, which blocks 50% of the sun and 25% of the heat. Shading tomatoes isn’t necessary for areas with hot afternoon rays.
Mulch tomato plants with a 2–3 inch thick layer to keep soil moist conditions. Replenish mulch as it decomposes in warm climates. Organic materials such as grass clippings, shredded bark, cotton hulls, and chopped leaves enrich the soil as they decay.
If temperatures stop falling below 90°F, any tomato plant with lush leaves and fruit moves into survival mode and needs sufficient water to remain healthy.
Stick your finger into the soil each morning to assess dampness. If the soil is dry at around an inch, it’s time to water.
Keeping the soil moist prevents fruit cracking and prevents blossom drop. In areas with sandy soil, like the Southwest, South Florida, and others, you may need to water plants daily or even twice a day or use drip irrigation to water regularly to the root system without effort.
Pick fruit early
Tomatoes stop releasing red pigments when temperatures reach 95 degrees, typically causing red fruits to turn orange. Therefore, most tomato ripening ceases when temperatures exceed 100°F during the day and 80°F at night. (Learn How Does a Greenhouse Work)
If you expect a heat wave, ripening fruit fares better off the plant than on. For example, cherry tomatoes can ripen your windowsill instead of leaving them on the plant.
Tomato Watering Techniques
1 to 1.5 inches of water per week is required for tomato plants in the garden. How much is 1 inch of water in the garden as it isn’t a standard measurement? A square foot of soil needs 1 to 1.5 inches of water, where a space 12 inches by 12 inches equals a square foot.
Unless there has been recent rain, tomato plants need watering every day or every other day, but container-grown tomato plants require twice-daily watering.
Before the sun gets too hot, early in the morning is the best time to water your plants. Incorrect watering leads to root loss, blossom end rot, reduced fruit production, stunted growth, and other issues.
Watering your tomato plants is essential to their survival and physiological functions.
Avoid flooding the plant and letting most of the water drain off (with nutrients and topsoil) when watering. Instead, water slowly, allowing the water to penetrate the soil.
When watering tomato plants, water deeply to around 6-8 inches below the soil surface. This encourages root growth and increases the plant’s ability to reach nutrients.
Water Tomato Plants Regularly
First, understand that there is no perfect formula for how often to water tomato plants. Just monitor the soil and see when it dries out. Don’t worry if it dries out immediately. Instead, try something new like mulching or a new watering method like a drip irrigation system.
Some locales require only one daily watering, and some require many daily waterings, or you can find watering once or twice a week is sufficient in damper regions.
If you observe your tomato plants drooping about noon, don’t panic. They’ll be back to normal by dusk, although if still drooping at dusk, the soil is too dry, and your plants need watering the following morning.
Plants drooping in the sunlight isn’t only because of a shortage of water; it’s also a plant’s moisture regulator of most plants to reduce the surface area in direct sunlight, which reduces transpiration (water loss from leaves, etc.) or evaporation.
Water Tomato Plants at the Roots
If you water plants using a hose, you’re probably watering the leaves and the stem. If you must water the leaves, do so early in the morning before the sun rises. You should cease watering the leaves if your water supply isn’t pure if it’s hard or if you’ve added fertilizer.
Watering at the roots does not mean wetting directly on the ground near the stem. However, it would help if you did it a few inches out from the stem to prevent washing away dirt close to the stem.
Use tomato craters to help water slowly to enter the root zone, thus eliminating the need to restrict the garden hose’s flow rate and water consistently. They also eliminate the need to pull weeds around tomato plants. In addition, they are red, thus helping photosynthesis by reflecting sunlight to the plant.
Water Tomatoes at Dawn
As previously noted, when you grow tomatoes, watering the foliage and fruit can raise disease risk. It’s simple: most tomato plant diseases thrive in damp environments. But this isn’t the sole requirement for the disease to flourish. They also require cool temperatures.
You shouldn’t water your tomato plant at night, even if they look droopy. Watering at dawn allows the plant to absorb water and begin photosynthesis, while water on the leaves, stem, or fruit dries off before the midday sun burns the plant through the droplets. (Learn How Far Apart To Plant Tomatoes In A Raised Bed)
Mulch is an organic layer of leaves, hay, coconut husk, wood, or pine cone bits. It’s organic, so it’ll decompose and provide plant food.
Mulching has quite a few benefits, the main ones being:
- Water retention
- Increased aeration when mixed with topsoil
- Source of nourishment
Because mulch slows soil evaporation, it reduces the need to water plants. So, if you mulch, you may only need to water once per day instead of twice or more.
Use Rainwater if Possible
Rainwater is ideal to grow tomatoes as it does not contain chemicals. Also, if you have hard water, the salts are not suitable for your tomato plants or any other plants.
If you have a rainwater collection system and underground storage, one of the finest places to use it is in your garden.
Watering Tomato Seedlings
Not so much watering is needed for tomato seeds and seedlings. Tomato seedlings are easy to germinate, but only the best results come from doing it correctly. Since this is the first stage of the tomato plant’s growth, you’ll want to give them a good start.