April may be considered early spring in most parts of the country, but normally in South Texas it is simply an introduction to summer time weather.

By late March and early April, night time temperatures are usually well above 60 degrees F.

Day time temperatures can, and often do, reach the century mark.

However, temperatures this spring have been cooler than normal, especially during the evening hours.

Although pleasant, cool night time conditions can cause tomato fruit set problems.

Fruit that set when temperatures were 55 degrees F. or colder will often be odd-shaped and of poor quality.

The low temperatures result in blooms that develop abnormally, in turn causing the fruit to be oddly shaped. When temperatures fall below 50 degrees and stay at that level, or lower for an extended period, fruit set can become severely limited.

In addition to low temperatures, excessive nitrogen fertilization, moisture fluctuations, and insect pressure can also result in poor fruit set.

Total crop loss may occur if one or more of these conditions is combined with lower than normal temperatures.

It is safe to say that these cooler than normal conditions will not stick around. It other words, it will get hot and dry before long.

When conditions do change, too more normal South Texas type weather, it will be necessary to irrigate the garden.

It is important when watering tomatoes that soil moisture not be allowed to fluctuate.

Soil moisture fluctuations can lead to numerous problems including cracking.

Tomato cracking is a physiological disorder that develops when irrigation practices allow soil moisture to fluctuate between excessively wet and excessively dry.

As a tomato reaches the mature green stage and the water supply to the plant is reduced or eliminated, the tomato will begin the ripening process.

At this time a cellophane-like wrapper around the outer surface of the tomato becomes thicker and more rigid in order to protect the fruit during harvest.

If the water supply is restored after ripening begins, the plant will resume moving nutrients and moisture into the fruit.

This will cause the fruit to enlarge; which in turn splits the cellophane-like wrapper around the tomato and results in cracking.

The best control for cracking is a constant and regular water supply.

Applying a layer of organic mulch to the base of the tomato plant is a big assistance in controlling fluctuations in soil moisture.