90 days ago I started growing 4 plants.About a month ago 2 of them wilted and died.The other 2 have hung in there but are also wilting and are very fragile. All the leaves are small and it looks like they have stopped growing.they are growing in dirt that was recommended to me. I have a 400 watt light I'm using and I'm growing them in a small space. 30in x 4 ft .Please help