Certified GKH Gardening Expert
I'm guessing it just rained really hard? Usually it is caused by a change in moisture/humidity. Sometimes it even happens after it gets really dry and you water it really good. Make sure to maintain proper soil moisture. Even though tomatoes are drought tolerant, doesn't mean they like it. Also, add dolomitic lime (agri-pel is the brand I use) and it will save you a lot of trouble in the future. Try adding a liquid silica to the water as well. Just be stingy as this will hinder the uptake of potassium, which your fruit need to bear properly. If you have any more questions feel free to shoot me a line at email@example.com or just ask here, and I'll be here to answer. Thank You!