Geraniums are often used as container plants or planted as annuals. They naturally grow in hot climates (zones 9-12), but that doesn’t mean they have to die off each winter in colder climates. Your geraniums will last for many years if follow this simple technique for overwintering them.
Dig your geranium.
Dig your geranium before the first frost. Carefully dig around and under your plant. Try not to severe any major roots.
Remove your geranium from the ground and shake the dirt off.
Shake off the dirt and rake through the top of the plant with your hands to remove any loose leaves. Inspect your plant for moldy leaves or rotted stems. Clip them before overwintering so they won’t spread to other parts of your plant.
Place your bare root geranium upside down in a cardboard box or paper bag.
You can put multiple geraniums in one box, but be sure not to pack them in too tightly. Packing upside down helps to retain moisture in the roots when overwintering geraniums.
Close up your box and store your bare root geraniums in a cool, dry place.
Your geraniums will overwinter best in a dark, cool area. 45-50 degrees Fahrenheit is an ideal temperature. Without light, warmth or moisture your geraniums will go dormant and “sleep” until spring. Basements are an excellent place to store your geraniums. Keep your box up off the floor to discourage mold. Do not tape your box. Instead, fold it loosely to allow for a little bit of air flow.
Remove your geranium and prepare it for replanting.
When spring approaches, its time to take your geranium out of the box. You might find that your plant looks shriveled and dry. Its very common for the leaves and upper branches to dry out. As you move closer to the roots, you should run into some green stems. If you are not seeing any green, don’t panic. Choose a branch near the bottom of the plant and gently scratch the top layer. You should see green underneath the top layer of “bark”. Prune your geranium to remove the dried branches. This may mean cutting it back completely. Don’t worry in 4-6 weeks you should notice new leaves emerging from the soil line.
Allow your geranium time to wake up before moving it outdoors.
Its a good idea to pot up your geranium and keep it in a windowsill for a few weeks before moving it outside. Pre-moisten the plant before potting it. Do not over saturate your soil. When you squeeze the soil it should clump easily, but no water should run out. When potting a dry plant, our first instinct is to douse it with lots of water. Resist the urge to over water it. Let the tops dry out slightly before each watering.