Overwatered plants dying!

So, the other plant looks ok. It was just the one plant you over watered? Using fabric pots, I use the 2 knuckle approach in the soil. If cool, but not damp, add enough water to drain slightly at the bottom. Depending on your heat and circulation, for example, 3 gal pots require water, every 3-4 days. Put some circulation on that grow bag, and ensure you have at least 76-78 degrees F, of heat. Don't water again, until your finger-test of the soil, explained above.