How to Overwinter Geraniums Geraniums are popular bedding plants, blooming from May through frost. However, the first hard frost doesn't have to be the end of your geraniums. They can be overwintered indoors by potting up individual plants, taking cuttings, or storing bare- root plants in a cool, dry place. Regardless of the method, the plants should be removed from the garden prior to the first frost. Water each plant thoroughly, then place the geraniums in a bright, sunny window or under artificial lighting.
Geraniums prefer cool indoor temperatures.
Daytime temperatures near 65 F and night temperatures around 55 F are ideal. During their stay indoors, water the plants thoroughly when the soil becomes dry. Occasionally pinch the geraniums to produce stocky, well- branched plants. Pinch off the lower leaves, then dip the base of each cutting in a rooting hormone. Stick the cuttings in a rooting medium of coarse sand or a mixture of coarse sand and sphagnum peat moss.