Tuberous Begonia Leaves Are Green But Curling Under

Question From: Durham, North Carolina, United States
Q: My tuberous begonia has bright green leaves, but they are curling under. Is this due to cool temperatures? I have them in a sunroom about 68-69 degrees. Thanks.

A: Your begonia may be suffering from lack of humidity. Place it on a pebble tray - a shallow tray filled with a layer of pebbles and water at a depth just below the pebbles. You do not want the pot to be sitting in water. The tray should be several inches wider then the plant. As the water evaporates it will provide humidity to the plant. Excessive salts in the soil will also cause leaf curl. You will usually see a white powdery residue on the pot or on the surface of the soil. The salts may come from your water of fertilizer. Try watering with bottled water. Leach the salts from the soil by running water through it for a few minutes. Cut back fertilizer to half strength. Best And Happy Yardening, Nancy