I am having issues with my beefsteak tomatoes here in Michigan. First garden since moving back to Michigan and all of my beefsteaks are getting concentric rings around the tops. They aren't actually cracks just rings the get larger as they radiate from the stem end of the tomatoes.
Howdy Neighbor, I'm not sure exactly why your having the problem but... To much consistant rain fall that doesn't saturate the ground can cause this. Mulching and crop rotation will help in the future. Water your tomatoes allot at one time. We have been dry this year in the thumb. Just the last couple rain falls has been a total of 3 inchs. The rain always goes below us or above us. I've been water all the time. I'm heading out to water my front lawn right now. Good luck. :>)