Within the last week, my perfectly healthy looking tomatoes (not just the ones sitting on the ground) have developed dark sunken patches on the bottom of the fruit. What can I do?

When we have rains followed by drought or near drought conditions—which seems rather common in this region—tomatoes can get a condition called “blossom end rot.” This condition is a disorder caused by a calcium deficiency. It can be caused by soil moisture fluctuations, as well as by excessive plant growth due to too much nitrogen given as fertilizer. There is nothing you can do about the tomatoes that are already affected. However, this condition can be prevented by avoiding over fertilization, applying regular irrigation to simulate an inch of rainfall per week, and mulching to maintain the soil moisture levels. For information about blossom end rot on tomatoes, see: http://www.ohioline.osu.edu/hyg-fact/3000/3117.html