My tomato stalk has turned brown all around the bottom with a brown streak running to the top of the plant. The leaves are affected at the base of the leaf stems and look kind of rotten. The leaves themselves look fine. It is a golden giant tomato. About three foot tall. It is planted in a five gallon bucket. I accidentally gave it a back to back dose of miracle gro but I dont know if that caused this or not. Any input would be greatly appreciated. Thank you.