Purple stems and curling leaves...Crazy weather or Disease?Help!

[shiner]

I am involved in a 3 family garden with raised beds with 50 tomato plants of different varieties and also have a small home garden with 20 tomato plants in raised beds. They were transplanted to the beds in successive dates of March 22 , April 5, and April 7th. The month of April has been one of the wettest on record in Arkansas. The earlier part of the month had some nighttime lows in the 60s. The last couple of weeks, the lows have dipped into the high 40s-low 50s. The last downpour we had was 8 days ago. Since then it has been sunny and dry but still in the high 40s at night. I fertilized the plants about 10 days ago with Tomato Tone and sprayed the leaves with Epsom Salt at a rate of 1 tablespoon per gallon. Since the rain has stopped the leaves have begun to roll inward and the stems have taken on a purple tint. The older plants are worse than the most recent transplants and the garden at my home is just beginning to show these symptoms. We have small tomatoes on some of the plants and up until this week they have looked robust and healthy. It seems like their growth has slowed down but is not stunted. I would like to believe it is the extremely wet weather and cold nights , but would appreciate any advice anybody can offer, Thanks!