Q.why is my eggplant not growing?
I planted one plant at my house and five at a garden plot. The one at my house is about two feet tall and at the garden have not grown at all.

Certified GKH Gardening Expert
There are many reasons this could happen, from a difference in soil quality to a difference in the amount of water received to a difference in the amount of nutrients received to a difference in the soil temps to a difference in nutrients to a difference in stress to the plant before it was planted.