I live in Phoenix AZ and it's freaking hot down here. I've planted about 6 tomato plants and all the tomatoes that have grown eventually splits open. I've put a sun shade over the plants to reduce the amount of sun, the plants get plently of regular water, so I have no idea what the problem is. I know it's not bugs because I meticulously inspect for insects. Any ideas on what it could be? Does anyone have a similar situation?