|The leaves on my gardinias turn black at the tips and continues at a slow pace toward the stem. It does not effect more than two or three leaves at a time.|
|Gardenias like average household temperatures (minimum 60F in the winter), bright light - but no direct sunlight - and moist soil. Use tepid, softened water. Mist the leaves frequently. If the leaves on your plants are turning black, it's a sign of low humidity near the plant, and too much water in the soil. In the winter it's best to water less frequently than when the plants are activiely growing.
Try to adjust the growing environment and your plants should respond favorably to the new conditions.