The leaves on my purple waffle plant are turning black and curling on the edges. It is a house plant with bright artificial light.
Purple Waffle Plant
Certified GKH Gardening Expert
This is normally an indication of a water issue, either it is not getting enough water or it is getting too much. With this plant, it needs lots of water and high humidity, so it is likely that you are under watering it. Keep the soil moist but well drained. You may want to set it on a pebble tray to keep the humidity high.