Bring potted geraniums indoors before frost. Geraniums are frost-sensitive, so act quickly.
Check plants for bugs and illnesses. Get rid of dead or damaged leaves. Clean pots to prevent bugs indoors.
Remove one-third to half the geraniums. This reduces plant size and promotes growth.
Place the pots in a sunny window with at least six hours of sunlight everyday. If natural light is insufficient, utilize grow lights.
Water plants sparingly. Geraniums need less water in winter. Dry the soil between waterings to avoid root rot.
Temperature should be 55-65°F (13-18°C). Keep them away from drafts and heat.