Garden Pests and Diseases: Tomato leaves yellow with green veins, 4 by caesarjr

caesarjr wrote:
I am growing tomatoes and other vegetables on my deck in pots. The leaves on two tomato plants and one tomatillo plant have turned yellow but the veins remain green. A third looks like it might be developing the same problem. I have checked the PH and it is about 6.5. I live in the Santa Cruz mountains in California. I use Miracle Grow for tomatoes as a fertilizer. I have also tried a foliar spray of epsom salt because I thought it might be magnesium deficiency. Any ideas? I would hate to lose them. They have tons of tomatoes on the vines and are 6\' tall! Thanks for any help you can give me.