Tomato Leaves Getting Yellow

Question

Hi, my tomato plants’ leaves are getting yellow. They are not at the bottom of plant; they are near the top of the plant. Some plant leaves are getting yellow like dots, and some leaves are getting yellow from the edge of the leaves. The plants are on the shelf, not on the ground, so it’s a bit high and nearly touching the roof of the greenhouse.  I have glass, so maybe the glass makes it too hot. Also, I always water them if they need it. They never dry. I don’t know if you can help.
Thanks
Enver

Answer 1

There are a couple of diseases that this could be. This disease key will help you pinpoint the exact disease:
http://vegetablemdonline.ppath.cornell.edu/DiagnosticKeys/TomLeaf/TomLeafKey.html