AMES, Iowa -- Geraniums have been a popular bedding plant for many years. Plants are commonly grown from cuttings. However, geraniums can also be grown from seeds. In addition, there are several methods for overwintering healthy, disease-free geraniums. Here are some tips from Iowa State University Extension and Outreach horticulturists on starting geraniums for summer planting. For more information on selection, planting, cultural practices and environmental quality, contact the ISU Hortline at 515-294-3108 or firstname.lastname@example.org.
When should I sow geranium seeds indoors?
Geraniums are relatively easy to grow from seeds. However, geranium seedlings are slow growing. Geranium seeds should be sown in early to mid-February to produce flowering plants for spring. Flowering occurs approximately 13 to 15 weeks after sowing. Suggested seed-grown geraniums for Iowa include cultivars in the Pinto, Maverick and Multibloom Series. (A series is a group of closely related cultivars with uniform characteristics, such as height, spread and flowering habit. Generally, the only characteristic that varies within a series is flower color.)
I have over-wintered several bare-root geraniums in paper bags. When should I cut back the plants and pot them up?
Remove the bare-root geraniums from their storage location and cut them back in mid-March. Prune out the shriveled, brown, dead material. Cut back to solid, green, live stem tissue. After pruning, pot up each plant and water thoroughly. Place the potted geraniums in a sunny window or under fluorescent lights. The plants should begin to leaf out in a few days. Bare-root geraniums that are pruned back and potted in mid-March should develop into healthy, attractive plants that can be planted outdoors in May.
I have over-wintered several geraniums as potted plants. The plants have gotten tall and lanky. When should I cut them back?
Cut back the geraniums in mid-March. Cut back the plants by one-half to two-thirds. Afterwards, place the plants in a sunny window or under fluorescent lights. The geraniums will begin to grow again within a few days and should develop into stocky, well-developed plants by May.
To learn more about horticulture through training and volunteer work, ask for information about the Iowa Master Gardener program at any county extension office.