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Tomatoes-Time to Think

Posted 2/8/2016

Heirloom Tomatoes

As the weather starts to become more like spring, it is time to think about tomatoes. When they are sweet, smooth, succulent and tangy, these vegetables, which are fruits, can be ambrosia. But when they come from a supermarket, they are often grainy, dry, and flavorless. Fortunately, we can grow our own, and encourage other people to grow their own, which they will want to share with us.

Tomatoes grow best when they get full sun, ample water, rich soil, and not too much heat. They succeed in pots or in a garden, but sometimes they develop disorders that break your heart. These can be particular problems in the desert.

Sometimes flowers appear, but do not result in tomato fruits. The flowers drop off. There is more than one reason why such an awful thing can happen.

If the plant produces flowers, but the temperature exceeds 85°F, or drops below 55ºF, the plant becomes stressed. If the stress is extreme, it cannot support flowers, much less fruit.

Another cause is incorrect watering. A plant watered too little will not be able to maintain flowers or fruit. Too much water, however, is just as devastating. In a heavy clay soil with poor drainage, the roots may drown and not perform necessary functions. As a result, the plant cannot maintain flowers.

Too much nitrogen fertilizer, or fertilizer applied when the plant is flowering, can cause blossom drop as the plant returns to making leaves. The best time to apply fertilizer, particularly nitrogen, is usually early in the season, when leaves are developing. Even a diligent gardener may find the bottom of a tomato is hard, black, and unappealing, but the rest of the tomato looks fine. This is “blossom end rot.” Some varieties are more susceptible than others. It is interesting, in a tragic way. A lack of calcium occurred when the fruit was a tiny part at the base of the flower. The developing fruit did not obtain enough calcium, and its cells did not grow properly. There was probably ample soil calcium, but the nascent fruit received insufficient water to deliver calcium to the rapidly growing tissue.

Radial cracks in a tomato

By the time you see the problem, it is too late to do help affected individual fruits. The blossom end is unappetizing, but the rest of the fruit is perfectly edible. The way to solve the problem is to prevent it. Keep the plant regularly moist, especially when flowers are present. Select varieties that require a shorter time to produce fruits. This information is in the catalog.

When the beautiful tomato you have nurtured and protected develops cracks, it is a disappointment. Cracks can be either concentric, or radial, like the spokes of a wheel. The answer to this is mostly proper watering. If a tomato is allowed to become too dry, and then overwatered, the skin cracks. This is a cosmetic problem, and the fruit is still edible.

If you select a good cultivar and keep the plant moist and well nourished, you have lowered the likelihood of disappointment when you grow your tomatoes.

Email or call Angela O’Callaghan, Social Horticulture Specialist for University of Nevada Cooperative Extension at 702-257-5581.

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