What is
Sunburned leaves
If your brand-new tomato plants suddenly develop gray-white blotches on the leaves in hot and sunny weather shortly after planting, it could be a simple case of sunburn.
This works best with smaller tomatoes, as larger tomatoes need a minimum of 6 to 8 hours of sun daily. 3. If you can't find afternoon shade, create some by using shade cloth over your plants. Shade cloth comes in many thicknesses - be sure the cloth you're using doesn't block more than 50% of the sunlight.
Six hours of light is adequate and eight hours can boost fruit production. Excess heat begins to enter the equation and temperatures above 85 to 90 degrees can reduce flower production and fruit development.
Overwatering generally makes the plant look almost like it's rotting, as in drooping and turning soggy brown. My guess is it is having Nitrogen problems. Any type of vegetable fertilizer you buy at the store should work fine.
Water correctly: Do not overwater. The first week tomato plants are in the ground, they need water every day, but back off watering after the first week, slowly weaning the plants down to 1 to 1.5 inches of water per week.
Tomato plants recover quickly from overwatering, usually in one to two weeks with treatment. How often should you water tomatoes? In the garden, water tomato plants deeply at the soil level once a week or twice weekly during hot weather depending on rainfall.
Leaf rolling and cupping
Corn and tomatoes are among many plants that commonly roll their leaves or cup in response to heat. Leaf surface area is minimized, and stomata (microscopic openings in leaves, like pores, that allow movement of moisture and gasses) close. Together, these reduce moisture loss in the plant.
Depending on where you live, you might want to expose your tomatoes to morning sunlight, to afternoon sunlight, or to a combination of the two. Morning sunlight provides high-intensity light without excessive heat, therefore you should consider morning exposure if you live in a region with a hot climate.
Pour on the water
(Too-dry tomatoes drop flowers sooner than well-watered ones.) In areas with sandy, fast-draining soil, like parts of the Southwest, South Florida, and Coastal South, you may need to water plants daily or even twice a day during the hottest days of summer.
So, it's best to water them in the morning before the sun hits them. In high heat and drought, I water them again in the evening. If your tomatoes wilt in the heat of the day even though you have watered them well in the morning, the cause is not lack of water.
To protect fruit, try draping cheesecloth over the vines in mid to late summer, or train vines to a cage to shade developing fruit. Training the vines makes it easier to pick tomatoes, and it reduces fruit rot that can develop when tomatoes touch soil.
Tomatoes need eight hours of daylight to flower. Sunlight gives your tomato plants the energy to produce fruit, so if your plant doesn't have enough sunlight, you're less likely to see tomatoes fruiting.
Plants will roll or cup leaves to reduce surface area and maintain the moisture in their leaves. Leaf rolling or cupping is a very common behavior in corn and tomato plants in response to heat stress.
Tomatoes are sun-lovers and require full sun, which means that they need unobstructed, direct sunlight for at least 6-8 hours a day, no cheating or skipping. Many people chronically overestimate how much sun an area receives.
Conclusion: White shade cloth (with about 35% shading) is the superior option for most tomato growers. It offers better protection against summer heat, reduces the risk of heat stress, and creates a more favorable environment for healthy tomato growth.
They much prefer 75 to 95. When temperatures get too hot during the day (over 85 degrees) or are too hot overnight (over 70 degrees) many vegetables including tomatoes and peppers will drop their blossoms. This will cause a noticeable drop off in harvest in a few weeks.
TOMATO WATERING TIPS
Water in the morning to the keep the soil moist through the heat of the day. Always water at the base of the plant — watering from above invites disease. Check tomatoes growing in pots often since they dry out quickly. Be consistent — fluctuations in water supply lead to cracking and blossom end ...
Cucumber plants like sun, but are prone to scorching, so some shade is preferable. Encourage greenhouse varieties to climb to boost yields. Harvest fruits early in the day while it's cool.
Some growers prefer to use a high-phosphorus fertilizer, indicated by a larger middle number. You can also keep things simple with a fertilizer especially formulated for tomatoes – usually with a ratio like 3-4-6 or 4-7-10. Most importantly, don't over-fertilize. Too little fertilizer is always better than too much.
Soil that contains a lot of sand doesn't hold water well and dries quickly. Because of this, tomato plants growing in sandy soil may need to be watered more often, about every three or four days. Clay soil, on the other hand, holds water well. Plants growing in clay soil usually only need to be watered once a week.
Other signs that they're getting too much sun include drooping leaves and a faded color. The soil may become dry, the plant may be hot to the touch, and sometimes the leaves can even crumble to the touch. While plants need water to grow, too much can be extremely detrimental.