My tomatoes plants are turning yellow starting from the ground and moving up. The leaves are yellow and curling. What is causing this and can they be saved.

There can be a number of causes for this. Just a few questions for you to start, though. What time of day do you water them? Where do you water them, at the base of the plants or as a shower over the entire surface of the plants? What kind of tomatoes are these?

I'm not saying that how and when they are watered as well as what kind of tomato plants they are is the cause to the problem that you are having. However, it would be good to first know about some of the conditions in which they are living.

Thanks!