The summer heat and long days are perfect for growing tomatoes.

With tomato harvest season beginning, gardeners are starting to inspect their crop a bit more closely. Unfortunately, gardeners are being disappointed by their findings — malformed fruit with a dark patch on the blossom end.

Here is what you need to do to enjoy a bountiful tomato harvest this summer:

The brown leathery patch on the bottom or blossom end of the tomato fruit is called blossom-end rot. It is not caused by a disease, and chemical sprays will not stop it. It is the result of a nutritional imbalance in the fruit, more specifically a calcium deficiency.

Calcium is an important nutrient in the development of tomato fruit. Although there is usually an ample supply of calcium in garden soil, it is not always available for fruit development. Warm spring temperatures cause rapid top growth with limited root growth. As the plant pulls calcium from the soil, it moves the nutrient in the water stream from roots to tops, bypassing the fruit and causing the deficiency. When the plant acclimates to summer weather, tops slow down and roots enlarge, bringing the plant back into balance. Available calcium can then be used for fruit development. Blossom-end rot does not normally develop on later fruit.

Water is the best way to stop blossom end rot. Keep the soil uniformly moist throughout the growing season. Plants that have water are able to take up and move needed nutrients more easily.

Next, do not over-fertilize. Plants that are excessively lush because of over fertilization are usually more prone to developing blossom-end rot. Slow sustained growth is better than fast forced growth. Finally, be patient. Although the first fruit to set does not develop normally and are not very appetizing, eventually the plant will work out the problem and you will harvest beautiful full tomatoes.