Proper light is necessary for good bloom. The amount of light that an African violet receives is also important for its health and overall performance. They thrive in moderate to bright, indirect light. Putting African violets in direct sunlight, can yellow and burn the leaves. The plant will also look stunted and have short leaf stem(petioles)..Dark green leaves and long leaf stems(petioles) indicate that the plant is getting too little light. A window facing east is usually the best, especially during the summer. For more even growth, give the plants a 1/4 of a turn about once a week. Most hobbyist growers prefer to grow their plants under artificial light.