It is caused by insufficient nutrients supplied to the flower organ when tomatoes are blooming. Especially when encountering low temperatures during the flowering period, the photosynthetic production on the leaves is less, the absorption capacity of the roots is weak, and less nutrients are absorbed. At the same time, nutrients must be provided for growth. In this way, the nutrients in the flower organs are reduced, and there are more deformed flowers. Generally speaking, large fruits, round fruits, and varieties with thick cork layer are more likely to crack than small and medium-sized fruits and varieties with thin cork layer.

Tomato fruit cracking occurs when the tomatoes are about to mature. The peel cracks, and the embryonic tissue and seeds inside are exposed with the peel. This causes the navel of the fruit to be torn apart like the palm of a cat's paw; some are on the fruit surface near the fruit stalk or on the surface of the fruit. Stripe-like cracks occur on the top or sides of the fruit.

   After the fruit cracks, it is easy to be infected by early blight, late blight or infected by bacteria and rot, seriously affecting the commercial value.

The main causes of tomato fruit cracking are:

1. Caused by insufficient nutrients supplied to the flower organ when tomatoes bloom.

   Especially when encountering low temperatures during the flowering period, the photosynthetic production on the leaves is less, the absorption capacity of the roots is weak, and less nutrients are absorbed. At the same time, nutrients must be provided for growth. In this way, the nutrients in the flower organs are reduced, and there are more deformed flowers.

2. Caused by inappropriate environmental conditions

   The main reasons are high temperature, strong light exposure and drought. Especially after a long drought, too much water is suddenly poured, which causes the pulp inside the fruit to expand rapidly and the sugar concentration to increase, leading to an increase in osmotic pressure, causing the rapidly expanding pulp to be incompatible with the expansion of the aging peel, causing the peel to rupture.

3. Characteristics of varieties

   Generally speaking, large fruits, round fruits, and varieties with thick cork layer are more likely to crack than small and medium-sized fruits and varieties with thin cork layer.

4. Related to the application of growth regulators

   Especially when growth regulators are used to protect flowers and fruits, the concentration is too high and the water and fertilizer cannot keep up, which can easily cause abnormal development of the ovary, or cause local physiological functions to be strong, causing physiological disorders and fruit cracking.

5. Excessive application of nitrogen fertilizer

   During the growth period, large amounts of nitrogen fertilizer but insufficient phosphorus and potassium fertilizers, excessive application of diamines that affect the absorption of calcium and boron, excessive nitrogen and phosphorus and insufficient potassium fertilizers, and long-term exposure to high temperatures above 30°C are all causes of umbilical fruit cracking.

Preventive measures for tomatoes to crack

• 1. Supplementary application of medium and trace elements
     Boron fertilizer is beneficial to plant flower bud differentiation, and calcium fertilizer can improve the toughness of peel cells and reduce the occurrence of fruit cracking.

   Therefore, during the fruit growth period, more potassium and boron fertilizers should be applied to control nitrogen fertilizers. The amount of potassium fertilizer is twice that of nitrogen fertilizer.

   You can spray high-calcium foliar fertilizer, 0.5% borax and foliar fertilizer containing calcium, boron and other trace elements during the flowering and fruiting period. Spray once every 7 to 10 days and spray 2 to 3 times in a row to prevent calcium deficiency. Tomato fruit cracking caused by boron.

• 2. Water properly
     Water properly. Pay attention to water management in the field before the red pomegranate blooms. Water when it is dry. During the fruit expansion period, keep the ground moist.

   Never use flood water to irrigate, drain water promptly after rain, and try to avoid drastic changes in soil dryness and humidity. Use small amounts of water and frequent watering to provide the water needed for the growth of red pomegranates and reduce the fruit cracking rate.

• 3. Reasonable pruning and leaf removal
     Do not remove the bottom leaves of Xihonghuan too early. All leaves are free from diseases, insect pests and yellow spots. They cannot be cut off prematurely. These leaves are used for photosynthesis and to prevent direct sunlight from hitting the fruit surface.
• 4. Choose high-quality varieties
     Variety selection is also critical. Choose varieties with thicker peels, resistant to storage and transportation, suitable for the local climate and environment, and highly resistant to stress.