your plant is not doing so hot. it either has a nitrogen defficiency or a nutrient lockup issue or both. You should watch what you are feeding it. Flush it out real good just pure water and keep water with only water for a few more weeks. You are growing soil so the soil can maintain growth for a short amount of time with natural nutrients. No need to risk nutrient lock up or poisoning your plant this early in the game.

The yellowing you see on the tops of your green leaves is nitrogen defficiency the bottom leaves dieing is nutrient lockup.