Depending on where or how you grow geranium plants, their needs will be somewhat different. Indoors, geraniums need lots of light for blooming but will tolerate moderate light conditions. They also need indoor temps of around 65-70 degrees F. (18-21 C.) during the day and 55 degrees F. (13 C.) at night. These plants need to be grown in well-draining potting soil as well. When growing geraniums outdoors, they require moist, well-draining soil similar to that of indoor potting soil with equal amounts of soil, peat, and perlite.