I want to grow patio tomatoes in a container, but they droop and die, soon. What am I doing wrong? I water once a day, feed them good food, but they seem to develop a fungus or something, at the root. Again, what am I doing wrong? Thanks.
First, check on your basic cultivation practices. This article will give you some tips: https://www.gardeningknowhow.com/edible/vegetables/tomato/growing-tomatoes-pots-containers.htm Pay special attention to watering -- overwatering can promote fungus and is as problematic as underwatering -- and fertilization -- once a week is plenty.
Secondly, try to determine what problem your plants are having. This article lists the common ones: https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-diseases.htm.
Make sure you discard soil from a sickly plant, don't put a new plant into it.