The established leaves have pretty large brown spots on them and the small, new leaves are turning brown on the tips. I read on one site that I should not mist the gardenia. However, I had read some years ago that gardenias like their leaves misted, so I'm not sure what to do. My main concern at this point is the existing leaves and the new leaves turning brown. As I said above, the established leaves have the larger brown spots on the leaf itself and the new leaves are browning on the tips.
Indoor Gardenia Brown Leaves
Certified GKH Gardening Expert
Gardenias love a moist environment, but they don't like being drenched and having water on their leaves. If your gardenias have brown leaves or you notice brown spots on them, this is usually due to:
Poor drainage – Gardenias love to be moist but not soaking wet. Be sure the plant is allowed to drain thoroughly between waterings.
Not enough humidity for indoor plants – Try using a humidifier in the room where you keep your gardenias.
Not enough sunlight – Gardenias need at least eight hours of full sunlight each day.
Pests – Check your plants for pests underneath the leaves, in the soil, and on the stems.
Improper pH - Check your soil pH (it should be 5.0 to 5.5).
Rhizoctonia Leaf Spot (fungal disease) - Leaves infected with this fungal leaf spot disease have tan to brown spots up to 1/4 inch in diameter, usually begins on the older leaves and spreads upward when the plants are watered excessively or from poor air circulation. Diseased leaves should be destroyed and sterilized soil should be used.