Mix 4 tablespoons of calcium chloride per gallon of water. Spray plants until solution begins to run off the leaves. Three applications are recommended at 7 day intervals. Also, you can mix 2 tablespoons to a gallon of water and spray 2 or 3 times a week. This procedure will help the problem.
Tomatoes can start to crack during warm, rainy periods, especially if rains follow a dry period.
The tomatoes simply expand too fast and the flesh is exposed through the skin. Some varieties are resistant to cracking. Again, the best way to avoid the problem is to keep the moisture supply as even as possible throughout the season. This is another kind of cracking or scarring in which tomatoes develop unusual swelling and streaks of scar tissue. This is not a disease.