Apply in a well-ventilated room. As always, follow label directions carefully. Q. I kept my geraniums in the, basement for the winter. They are starting to grow. This is a common problem with wintering geraniums.
Basements often are to warm and light to keep geraniums dormant.
If you have the space, plant the geraniums in pots, and prune the tops back to 4 to 6 inches. Move them to a warm, sunny spot and start watering. If you don't have the space, move plants to a cooler, darker location. Keep them away from the furnace, heat ducts, ceiling,and other warm spots in the basement, and keep your fingers crossed. The top of my houseplant soil is white and crusty.