Why are my tomato leaves going brown and dry around the edges?

I would slow down on the plant food and try watering them less.You can cut the limbs with brown leaves,cut them at the stalk.It want hurt the plant to get wet either.Try misting the leaves in the evening after the sun has gotten off of them.You shouldn't have to feed them any more,it sounds like you may be over feeding them.They love contact moisture so mist them regularly.