Answer: Based on your description I suspect what is happening is that growth cracks are being invaded by fungal infection. Unfortunately some varieties are simply more prone to growth cracks than others. The cracks themselves are usually caused by either a very fast rush of growth in hot, wet weather or by uneven moisture levels at critical stages of development. The best things you can do are to keep the plants growing steadily but avoid overfeeding, and try to keep the soil evenly moist at all times rather than allowing it to go dry and then very wet. This will help the tomatoes swell at a more even rate in better harmony with the skin growth. Also, remove any rotting fruit immediately to reduce the chances for reinfection. Finally, sometimes the cracks will heal over with no harm done.
Q&A Library Searching Tips