Geraniums are wonderful, easy-to-grow plants that bloom on and on all summer. As the weather cools, they usually put on a great show so it's no wonder many gardeners want to bring them indoors during the winter and keep them until next spring. Of all your outdoor summer bloomers, geraniums can probably make the transition most successfully using one of several available methods.
Various geraniums grow successfully in our area, but some are better suited to overwintering than others. Perennial geraniums (genus Geranium) simply stay out in the garden with all the other perennials. Another common name for perennial geraniums is Cranesbill. These are also called true geraniums. All the rest of the geraniums we grow in our area are in the genus Pelargonium. This grouping includes the traditional zonal (cutting) geraniums as well as Ivy, Scented, Seed and Regals (a.k.a. Martha Washington). Zonal, Scented, Seed and Ivy geraniums are the most likely to winter successfully indoors. But Regal (Martha Washington) geraniums need special attention both during the growing season and during the winter. Regal geraniums need cool temperatures in order to bloom profusely. Winter them in the house in a cool 50° to 60° room that has a south or west window.
Storing Them Dormant
Often you will read or hear about storing geraniums bare root and dormant in the basement over winter. The success of this method depends on the place you store them. When people had cold cellars or pump rooms, it worked quite well. Temperatures were cool and humid then. Most modern basements are much too dry and warm. But if you want to try this method, just dig up the plants before a killing frost in the fall. Cut the branches back about half way. Remove as much of the dirt from the roots as possible. Do this carefully because geraniums are rather brittle. At this point, they were traditionally hung from the rafters until spring. If you don't have rafters, you can bag them separately in paper grocery sacks. Leave the sacks open for ventilation.
Check your plants every month or so to see if they are getting too dry and shriveling. If necessary, spray them with water. If they get so dry the stems begin to shrivel, take them out and soak them for an hour or two in tepid water. Remove them from the water and allow their surfaces to dry before putting them back in the paper bags. Plants that have been overwintered in this manner may take several weeks to begin growing again in the spring. Soak the geraniums for several hours, roots and all, in water that contains a transplant fertilizer mixed at half strength. To get an early start, you can pot up the plants indoors several weeks before the last frost and transfer them into the ground later. When planting directly outdoors, be sure to wait until after all danger of frost is gone.
Keeping Them Growing
Geraniums do well as house plants if you can provide them with a cool location and lots of light. Dig them up and pot them just before a frost occurs and cut them back. Check the plants over carefully to make sure they are free of insects or disease. Wintering indoors is stressful; only take indoors plants that are in good condition. Water the plants thoroughly when you first bring them in. Geraniums prefer to stay relatively dry compared to most plants.
Cuttings
It is possible to take cuttings instead of bringing in whole plants. A cutting is simply a piece of the mother plant. For best success, use tip cuttings. Cutting off the last 3-5 inches of a branch makes tip cuttings. Remove any flower buds that may be on the cutting, also remove leaves from the lower half of the cutting. To help promote fast rooting, dip the cut end of the geranium into a rooting hormone. Place the cuttings about two inches deep in a clean pot filled with Bachman’s Mighty Earthä potting soil.
The cuttings should be rooted in individual pots. Place a clear plastic bag over the cuttings and pot. For the first few weeks, keep the cuttings in good light, but out of the direct sun. The potting soil should stay evenly moist. After 3-4 weeks the cuttings will have developed strong roots. After they have begun to root, remove the plastic bag and give the cuttings stronger light. When you begin to see new growth, move them to a cool, sunny location and feed monthly with a water-soluble fertilizer such as Bachman's Mighty Bloom™ at half strength. If you don't have adequate light indoors, geraniums do very well under fluorescent or incandescent plant lights. Given enough light, geraniums will develop into well-branched, strong plants by spring. If light is not adequate, they may tend to grow rather tall and spindly. Remember, geraniums like it on the dry side.
Next Season
Geraniums that have been overwintered can make very satisfactory plants the next season. Those brought through as cuttings will be completely new, productive young plants, just like those you might buy in spring. The geraniums you overwinter actively growing will be larger plants with heavier stems. They will bloom almost as much as a young plant. Geraniums that have been overwintered dormant take several weeks to recover in the spring and often need to be cut back to improve their shape and productivity. No matter how you overwinter your plant, don't put them outside until you are sure there is no danger of a killing frost.
Additional Bachman's Information
Geraniums: Zonals, Seed and Ivy
Fertilizing Annuals and Perennials
Watering Basics
Recommended Products
Bachman’s Mighty Earth™ Potting Soil
Vermiculite and Perlite
Rooting Hormone
Quality Pots and Containers
Bachman’s Mighty Bloom
Grow Light Fixtures and Bulbs
Bachman's-Grown Geraniums
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