What’s the best way to save geraniums through the winter?
—Karen Jackson, Minneapolis, MN
The best way to hold geraniums over winter in cold climates is to pot them up, trim them back substantially, and keep them growing by a bright window or under fluorescent lights. But few of us have enough space to keep pots of geraniums growing actively indoors.
Some people have good luck knocking most of the soil off the roots, then storing the plants in paper grocery bags in a cool, damp basement—the cooler and damper, the better. Assuming the geraniums don’t shrivel and die, by late winter or early spring you’ll see little sprouts developing on the stems. That’s the signal to trim back the old growth, pot up the plants, and move them to a bright location where you’ll begin to water and fertilize them until it’s warm enough for them to go outdoors again.