Growth cracks symptoms
There are two types of cracking found on tomato fruit. Concentric cracking are cracks that vary in depth and size found in circles around the stem and radial cracking which are cracks running from the stem to the blossom end of the fruit.
Cause of growth cracks
Growth cracks occur when there is a rapid influx of water and solutes into the fruit and at the same time ripening of the fruit. The epidermis is at this stage not elastic enough to cope with the sudden expansion and cracks. A sudden increase in temperature can also cause cracking since it increases the development of gasses that expand the fruit. A sudden lowering of nutrient EC can also cause fruit cracking which is the same effect that prolonged rain has in field tomatoes. The growth cracks vary in depth and usually heals after a couple of days. The problem is these growth cracks can rupture during harvesting and handling.
Controlling growth cracks
Plant resistant varieties. More tolerant cultivars do not crack until they are mature. Good fertilization management will reduce the occurrence of this disorder. If possible, install an alarm system which checks the EC of the nutrient solutions. As soon as it goes below a certain level, you are notified, either through an alarm system on the farm or electronically (phone text message or email).
So growth cracks is a function of variety and nutrient management.