You can use any of the following methods to save geraniums and other potted plants for next spring. In their natural habitat, there is no one running around pulling them out of the ground and hanging them upside-down for the dormant season, but if you want to do that, you can. If they are planted in the ground, dig them up before they get a frost and shake the soil off the roots. Hang them in a dry location where the temperature will remain in the 40s or low 50s.
It might be necessary to soak the roots for an hour or so once a month to prevent them from completely drying and dying. All the leaves will die, but the stem should remain plump and not shriveled up. Next March, repot them and cut off any dead stems. If the stems are too long, go ahead and cut them back in the spring.
If you have a sunny window or a greenhouse, geraniums can be left in the pot and grown all winter long as a houseplant. They do prefer more than 10 hours of daylight each day, and 12 is even better. In areas with short days during winter, you may need to supplement with grow lights to get them to bloom. Or you can just let them slow down their growth and go partially dormant for the winter. Be careful to not overwater them. They are succulents that don’t need a lot of water.
If you don’t have a place to grow the geranium as a houseplant, just bring it indoors and don’t water it. Store it in the same location as you would the uprooted plants, in dry, cool conditions. Check on them occasionally and add a little water to the soil now and then to keep them barely alive. Next spring, cut the dead stuff off and begin watering and place them in a sunny window.
Another method involves more work but can get you more plants. Cut the top four to six inches off each branch. Discard any flower stalks, even if they are just buds. Take off all the leaves on the bottom two or three inches of the stem. Dip the cutting into rooting hormone powder or liquid, available from garden centers. Place the stem in sand or perlite and add water. A whole tray of them can be made from recycled plastic containers. Put them in a sunny window, but not in the sun, or under a fluorescent light.
It will take a month or two for them to begin rooting. Then they can be potted up, or you can wait until spring. Be sure to keep them watered. A little diluted fertilizer can be used after they are rooted. The bottom half of the plant that the cuttings came from can be saved as in the other methods, or it can be thrown out.
Some other potted plants from the garden can be saved in the same ways. The common dracaena spike plant that is used in the center of a pot can be saved using all the geranium methods. Large angel wing or dragon wing begonias, Boston fern, ivy, croton, dieffenbachia, and other houseplants that were in containers during the summer can be used as houseplants during the winter.
