Plants grown indoors like bright light.
Windows facing the south or west have the best light.
Try to place the plants close to the window to take advantage of all the light. The further away from the window, the darker it becomes. A plant will tell you when it isn't getting enough light, because its stems will be thin. If you don't have a bright window, try using grow lights. Remember to have the light about 6 inches above the plants and leave it on for 14-16 hours each day.