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Horticulture and Home Pest News
Horticulture & Home Pest News is filled with articles on current horticulture, plant care, pest management, and common household pests written by Iowa State University Extension specialists in the Departments of Entomology, Horticulture and Plant Pathology.

How to Overwinter Geraniums

This article was published originally on 9/17/1999

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.

Potted Plants

Carefully dig up each plant and place in a 6- to 8-inch pot. Prune the geraniums back to 1/2 to 1/3 of their original height. 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 65Å¡F and night temperatures around 55Å¡F are ideal. (Geraniums become tall and spindly when grown in warm, poorly lit areas.) During their stay indoors, water the plants thoroughly when the soil becomes dry. Occasionally pinch the geraniums to produce stocky, well- branched plants.

Cuttings

Using a sharp knife, take 3- to 4-inch stem cuttings from the terminal ends of the shoots. 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. Clay or plastic pots with drainage holes in the bottom are suitable rooting containers. Insert the cuttings into the medium just far enough to be self-supporting. After all the cuttings are inserted, water the cuttings and medium thoroughly. After the medium is allowed to drain, place a clear plastic bag over the cuttings and container to prevent wilting of the cuttings. Then place the cuttings in bright light, but not direct sunlight. The cuttings should root in 6 to 8 weeks. When the cuttings have good root systems, remove them from the rooting medium and plant each rooted cutting in its own pot.

Bare Root Plants

Dig the geraniums and carefully shake all the soil from their roots. Then hang the plants upside down in a cool (45-50Å¡F), dry place. An alternate method is to place 1 or 2 plants in a large paper sack. Once a month during winter, soak the roots of each plant in water for 1 to 2 hours. Most of the leaves will eventually fall off. (The paper sack method is much cleaner than the hanging method.) In March, prune or cut back each plant. Remove all shriveled, dead material. Healthy, live stems will be firm and solid. After pruning, pot up the plants and water thoroughly. Place the potted geraniums in a sunny window or under artificial lighting. Geraniums that are pruned and potted in March should produce green, attractive plants that can be planted outdoors in May.

Most annuals, such marigolds and petunias, are relatively inexpensive compared to geraniums. Gardeners who plant large numbers of geraniums can reduce their gardening expenses by overwintering their geraniums indoors.



This article originally appeared in the September 17, 1999 issue, p. 121.

Year of Publication: 
1999
Issue: 
IC-481(23) -- September 17, 1999