The Secret to Keeping Your Geraniums Healthy This Winter, According to Experts

For many, geraniums signal the unofficial start of summer, popping up at Memorial Day parties as a vibrant symbol of the warm, sunny days to come. These beautiful blooms can thrive throughout the summer months—as long as it’s not too hot—but once the threat of frost appears, it’s time to consider how to get them through the winter. 

But when should you bring these cheerful plants indoors, and what’s the best way to overwinter geraniums? As is often the case, the answer depends on where you live—though it’s also somewhat rooted in where and how you plan to keep them over the winter. We spoke to two experts about why, when, and how to overwinter geraniums in order to maximize the plant's life.

When to Overwinter

In short, overwintering means moving a plant indoors during the cooler winter months. This process preserves them until the next spring, protecting them from frost and harsh temperatures. The big question, though, is when you should start to move your blooms inside.

According to Matt Mattus, a senior horticulturalist and the director of special projects at the American Horticultural Society, it’s “earlier than you think you should.” He recommends bringing your geraniums in about three weeks before the first frost. 

Gary O’Malia, owner of Larry O’Malia’s Farm & Greenhouse and a fourth-generation farmer, echoes that sentiment. The first week of October used to signal the start of heavy frosts at his Pennsylvania-based farm, but that date has been pushed back a few weeks in recent years. 

Make Preparations

Before you bring your geraniums inside, it's important to keep a few things in mind. Firstly, Mattus highly recommends repotting your flowers in fresh soil before bringing them inside. “That's really important for these plants," he says. "They need oxygen and air spaces in the soil.”

In particular, he says to buy soil that’s comprised of at least fifty percent cactus mix, which you can find at a garden center like Home Depot. This ensures the plants maintain a healthy pH level over the winter, all while improving their ability to absorb required nutrients. 

Another thing to keep top of mind is the risk of diseases and bugs. O’Malia recommends using an insecticide on the plant about two weeks before bringing it inside, especially if you plan to keep it near others, like year-round houseplants. This method helps to deter pests that could negatively affect healthy indoor flora. Repotting can also help cut down on potential issues.

Use a Warm, Bright Location

The best way to overwinter a geranium is to give it the full houseplant treatment and provide it with an environment that best matches its natural needs. “Bring the pots indoors, and keep them somewhere warm in the sunniest, brightest spot you have," says Mattus. "You can also put them under artificial lights.” 

Once inside and at room temperature, the flowers will stay out of dormancy. With this method, they'll be ready for spring as soon as it’s safe to return them to their outdoor home. That being said, since they're not dormant, you'll want to provide adequate water so the soil doesn't dry. Use a weak fertilizer every few weeks to maintain a lush plant. 

Try a Cool Spot with Moderate Sunshine

You can still successfully overwinter your geraniums even if you don’t have a brightly lit, warm place to keep them. The ideal scenario, according to O'Malia, is an environment that's about 50 degrees Fahrenheit with some sunshine.

Since the temperature is a bit cooler, the plant will likely go into dormancy. Make sure to still water occasionally to keep the plants as healthy as possible—if your home is dry, then you may need to water them once a week. If the air is more hospitable, then you can likely wait longer in between watering. When in doubt, a simple touch test will determine if the soil is dry and if the geraniums begin to wilt, then you'll know you’ve gone too long. 

In addition, make sure to pinch off any buds. O’Malia notes that when a plant is stressed, the first thing it wants to do is to flower, since its goal is to reproduce. However, those new buds can cause unnecessary strain on a dormant plant.

Overwinter Cuttings

Overwintering from cuttings is another option, and cuttings always grow better, as per Mattus. With this method, take cuttings from your existing geranium, plant them, and tend to them over the winter.  

Before you start, make sure the cutting is always from a new, healthy growth. While you can take cuttings from older, woody parts, the young plants always grow better. "Cut the plant back by two-thirds in the spring and wait for the new flush of growth before taking a cut," says Mattus. For fall cuttings, he recommends that each cut have at least two nodes—make the cut just below the second node.

Once you've taken cuttings, let them callous over and dry for about a day before planting them in soil. This allows time for a crust to form on the cutting and reduces the risk of rotting. Remember to use potting soil rather than trying to root it in water.

The Bareroot Method

In the past, many home gardens used the “bareroot” approach to overwinter geraniums and other annuals. O’Malia remembers his father’s customers using this method—they would uproot the plants, and then hang them upside down in cool, dry, and dark areas, like attics. There, the geraniums would go dormant for the winter, only to be replanted and revived in April.

“[The geraniums] would look pretty rough, but they’d replant them and they’d start growing," he says. "It took a while for it to turn into a nice-looking plant again.” All that being said, O'Malia doesn’t recommend this method, especially if you want your geranium in top shape for those Memorial Day gatherings. 

The bareroot was popular in the 1940s and only works because many geranium species have succulent stems. "That's why they survive in the cellar when you hang them upside down—but they kind of suffer," O'Malia says.

Mattus agrees: Geraniums overwintered using the bareroot method don’t look great come spring, and he doesn’t recommend it. Still, the bareroot approach is a feasible way to get your geraniums through the winter. If you’re up for a challenge and want to try something a bit old-school, then it may be worth a try.