Most gardeners are a bit thrifty by nature, growing their own vegetables or making more perennials by dividing existing plants. But did you hear about the guy who was so cheap he bragged to his wife about saving a dollar by running home from work behind the bus instead of riding? His wife replied that he could have saved $15 if he had waited and ran behind a taxi.
One way for gardeners to save money is by bringing geraniums indoors for winter instead of letting them freeze. This isn’t meant to reduce the profits of our hardworking garden centers. Instead, if we save our own geraniums for next spring, we can spend that money on other plants, trees and shrubs.
There are two general ways to keep geraniums from year to year. You can bring the original plants indoors, or you can start new plants from cuttings. Or a combination.
The original plants can be kept indoors by several methods. Some gardeners move their potted geraniums to a cool spot in the basement, where they remain partially dormant during winter with minimal watering, and are brought back into active growth in spring. A few gardeners follow the age-old practice of storing geraniums bareroot in a root cellar-type atmosphere. Geraniums can also be kept actively growing in a sunny window.
The following is the method we’ve used for years, which is highly successful and lets you winter a number of plants in a fairly small area, either in windows or under electric lights.
- Before they’re injured by fall frost, remove geraniums from outdoor planters or flower beds by gently digging or lifting the plants and shaking the soil from the roots.
- Instead of trying to overwinter geraniums with all their large summer growth, I prefer to cut each plant back to 3 inches above soil level. This removes most of the tops, leaving only stems and a few lower leaves. More plants fit in a limited space, and they quickly sprout new healthy, compact growth.
- The goal is to produce compact, well-branched plants in 4- or 5-inch pots by next spring.
- Pot the pruned geraniums into individual 4- or 5-inch diameter pots using top-quality soil like Miracle-Gro Potting Mix, or a mix recommended by your local garden center. I use 4-inch diameter plastic pots that I’ve recycled.
- Locate the plants in a window with direct sunshine. South windows are best, followed by east and west.
- If a sunny window is lacking, geraniums grow very well under fluorescent or LED lights, with automatic timers set for 16 hours on and 8 hours off. We grow ours in a corner of the basement under shop-type fluorescent fixtures containing one warm and one cool tube, although we’ll soon be transitioning to LEDs. Locate plants so the lights are within an inch or 2 of the geranium tops.
- Fertilize once a month with a water-soluble fertilizer.
- Allow the geranium soil to dry out very well between waterings. If a finger inserted to the first joint feels any moisture at the fingertip, don’t water. If in doubt, wait a day and then check again. If in question, err on the dry side.
- Continue to grow the plants during winter as you would other houseplants. About March 1, pinch back any winter growth that became spindly, and remove blossoms and flower buds. Begin water-soluble fertilizer every two weeks. The geraniums will branch beautifully and will be in prime conditions for planting outdoors in May.
The second method for preserving geraniums is by taking cuttings in September, which is great for starting new plants to replenish any that are old and woody. Here is the method we use.
- From the fresh, outer tips of geranium stems, break off cuttings about 3 inches long and trim off all lower leaves with only the top two or three remaining.
- Root the cuttings in moistened potting mix in recycled cell packs, with the lower inch or 2 planted in the mix.
- Water after planting the cuttings, but water sparingly after that to prevent rot.
- Outdoors in a sheltered location in filtered sunlight is ideal.
- Cuttings will root in about two weeks. When the soil cube is well-filled with roots upon careful examination, the plants are ready to pot into 4-inch diameter pots and grown in a sunny window or under lights.
Don Kinzler, a lifelong gardener, is the horticulturist with North Dakota State University Extension for Cass County. Readers can reach him at firstname.lastname@example.org.