I have one of my tomato plants that is not up to snuff with the rest, and it's leaves are curling as if it didn't get enough water. It's the same cultivare as those next to it, and they all get treated the same. I'm not sure if I should remove it or let it be. It's about a foot shorter then its neighbors. I don't see any evidence of aphids or other insects.
Politicians are like diapers, they need to be changed often, and for the same reason.
