Tomato troubles, plastic covering and tasty veggies

What does it mean when the bottom leaves of my tomatoes turn yellow? It means that the bottom leaves are not healthy. If they turn yellow late in the growing season, it means only that the leaves are getting old. Yellow tomato leaves should not be occurring in early summer.

There are many causes for yellow leaves (and they usually start at the bottom of the plant) but most yellowing in most of the country comes from tomato diseases. Fortunately, in Montana we can forget about diseases like early and late blight. They are the curse of tomato growers in the eastern United States.

It is conceivab...