Pests and Problems of Rosemary Plants

The biggest problem with growing rosemary indoors is its tendency to get powdery mildew. Powdery mildew is a white, powdery fungus that can develop if the surrounding air is humid and there is not enough air movement.Powdery mildew won't kill your rosemary, but it will weaken the plant. Keep the humidity low by allowing the soil to dry somewhat between waterings, keeping the plant in sunlight and, if necessary, running a fan for a few hours a day to create a breeze.