Overwintering geraniums in pots is straightforward once you understand the two main approaches: keeping them growing slowly indoors through winter, or pushing them into dormancy in a cool, dark space. Most garden “geraniums” are actually pelargoniums, tender perennials from southern Africa that cannot survive frost but can live for years if protected. The method you choose depends on how much light and space you have, and both work reliably with a little attention.
The Plants We Are Actually Talking About
When gardeners say “geranium,” they almost always mean plants in the genus Pelargonium, not the cold-hardy cranesbills that belong to the true genus Geranium. That distinction matters because true geraniums are perennials in most temperate climates and need no indoor protection. Pelargoniums, on the other hand, are native to regions where winter freezes do not occur. They evolved to handle dry seasons, not cold ones, which is why they respond well to dormancy storage but die when exposed to sustained temperatures below about 30°F (roughly −1°C). The common zonal types with round flower clusters, ivy-leaf trailing types, and scented-leaf varieties are all pelargoniums and all candidates for overwintering.
Method One: Keeping Them Growing Indoors
If you have a bright windowsill, sunroom, or grow light setup, you can keep your potted geraniums actively growing through winter. This is the simpler method in concept, though it asks more of your indoor environment. Bring the pots inside before the first frost, ideally when nighttime temperatures start dipping below 45°F (7°C). Before you move them in, inspect closely for aphids, whiteflies, and spider mites, all of which will explode in a warm indoor setting if they hitch a ride. A strong spray of water over the foliage and a check under the leaves catches most stowaways.
Indoors, geraniums need at least four to six hours of direct sunlight a day. A south-facing window works in most northern-hemisphere homes. Without enough light, the stems stretch and weaken, leaves yellow, and you end up with a leggy plant that takes months to recover in spring. If natural light is scarce, a basic full-spectrum grow light positioned a few inches above the plant for 12 to 14 hours a day fills the gap cheaply.
Watering drops dramatically compared to summer. The combination of shorter days, cooler indoor air, and no wind means the soil dries far more slowly. Water only when the top inch or so of soil feels dry, and never let the pot sit in a saucer of standing water. Overwatering is the leading killer of indoor-overwintered geraniums because soggy roots invite fungal rot. You can skip fertilizer entirely from late fall through mid-winter. If the plant still looks healthy in February and you want to encourage new growth before moving it back outside, a half-strength liquid feed every few weeks is plenty.
Method Two: Dormancy in a Cool, Dark Space
Not everyone has a sunny window to spare. The dormancy method works well for gardeners with an unheated garage, basement, crawl space, or enclosed porch where temperatures stay between roughly 40°F and 50°F (4–10°C). The goal is to slow the plant’s metabolism to a near standstill so it survives on stored energy until spring. Research on pelargonium cuttings has shown that cooler air temperatures significantly increase carbohydrate levels in the plant’s tissues, particularly sugars like sucrose, and that those higher sugar reserves are directly linked to better survival rates and reduced leaf loss.1Postharvest Biology and Technology. Response of post-storage carbohydrate levels in pelargonium cuttings to reduced air temperature during rooting and the relationship with leaf senescence and adventitious root formation In practical terms, cooler storage lets the plant bank more energy, which it draws on to push new growth when conditions improve.
To prepare the plant, cut the stems back to about four to six inches above the soil line. Remove any dead or yellowing leaves and spent flowers. Some gardeners remove the plant from its pot and shake off excess soil, wrapping the root ball loosely in newspaper or placing it in a paper bag. Others leave the plant in its pot. Both approaches work. The key variable is temperature: too warm and the plant tries to grow in the dark, exhausting its reserves on weak etiolated stems; too cold and you risk tissue damage. That 40–50°F range is the sweet spot.
During dormancy, you still need to water occasionally, roughly once every three to four weeks, just enough to keep the roots from drying out completely. The soil should feel barely damp, not wet. Check the stems periodically by giving them a gentle squeeze. A firm, slightly flexible stem is alive. A mushy or hollow stem is rotting and should be cut away. Expect some leaf drop; this is normal. The plant is shedding tissue it cannot support in low light, which is actually a healthy response.
The Bare-Root Alternative
A third approach, popular in colder regions with limited indoor space, is to pull the plants entirely out of their pots, shake off all the soil, and hang them upside down in a cool, dark space or lay them in a cardboard box lined with newspaper. This bare-root method works because geraniums have thick, semi-succulent stems that store enough moisture and carbohydrate to survive several months without soil. It sounds dramatic, but generations of gardeners in the upper Midwest and northern plains swear by it.
The trade-off is higher mortality. Without any soil moisture buffer, the roots and stems are more vulnerable to desiccation. Every few weeks, take the plants down and soak the roots in lukewarm water for an hour or two, then let them dry before returning them to storage. If stems shrivel and become papery, the plant has likely dried out beyond recovery. Expect to lose maybe a quarter of your plants this way in a typical winter, which is still a good return if you started with a large collection and had nowhere to keep pots.
Choosing the Right Pot and Soil for Winter
If you plan to overwinter geraniums in their pots, the container itself matters more than you might think. Terracotta pots wick moisture away from the soil faster than plastic, which can be an advantage in a damp basement where root rot is the main threat. In a dry heated room, though, terracotta may dry the root ball out too quickly. Plastic or glazed ceramic holds moisture longer and needs less frequent watering. Whichever material you use, drainage holes are non-negotiable. A pot without drainage, or one sitting in a non-draining decorative sleeve, is a death trap for a plant on a reduced watering schedule.
Soil mix matters too. A standard potting mix with perlite or coarse sand for drainage works well. Avoid heavy garden soil, which compacts in a pot and holds too much water. If you are repotting before bringing the plant in, resist the urge to upsize the container. A pot that is too large relative to the root ball holds excess moisture around roots that are not actively growing, creating exactly the soggy conditions that encourage rot. Keep the pot size snug.
Common Problems and How to Handle Them
Most failures during overwintering trace back to one of three issues: too much water, too little light, or fungal disease. Overwatering and insufficient light have already been covered, so let’s focus on the diseases that show up specifically during winter storage.
- Botrytis (gray mold): Appears as fuzzy gray patches on stems and leaves, usually where dead tissue meets living tissue. It thrives in cool, humid, stagnant air. Remove affected parts immediately, improve air circulation around the plant, and reduce watering. A small fan running on low nearby helps prevent recurrence.
- Pythium and root rot: Stems turn black and mushy at the soil line. This is almost always caused by overwatering. If caught early, you can unpot the plant, trim away all rotted roots and stem tissue, let the remaining roots air-dry for a day, and repot in fresh dry mix. If the rot has reached the main stem, the plant is usually lost.
- Edema: Small corky bumps appear on the undersides of leaves. This is not a disease but a physiological response to the roots taking up more water than the leaves can transpire, common in low-light indoor conditions. It is cosmetic and not fatal. Reduce watering and increase light if possible.
Pest problems also shift indoors. Fungus gnats breed in consistently damp soil, so letting the surface dry between waterings keeps them in check. Whiteflies and spider mites, which may have been invisible outdoors where natural predators held them down, can build populations rapidly indoors. A periodic wipe of the leaves with a damp cloth or a spray of insecticidal soap handles minor infestations before they become serious.
Waking Plants Up in Spring
The transition back to outdoor life is almost as important as the storage itself. For dormant-stored plants, start the revival process about six to eight weeks before your last expected frost date. Move the pots or bare-root plants into a bright, warm room. Repot bare-root plants into fresh potting mix, and water all plants thoroughly. New growth should appear within a week or two. Once green shoots emerge, begin watering normally and give the plants as much light as possible.
For plants that spent winter growing on a windowsill, the shift is less dramatic but still needs care. Do not move them straight from an indoor window into full outdoor sun. The leaves have acclimated to lower light levels and will sunburn, turning white or brown in patches within a day. Instead, harden them off over about a week: start with a couple of hours of outdoor morning sun in a sheltered spot, then gradually increase exposure. After seven to ten days, they can handle a full-sun position.
Whether the plant was dormant or active, spring is a good time to cut back any leggy or weak growth and pinch growing tips to encourage branching. Resume regular fertilizing once the plant is outdoors and actively growing. A balanced liquid fertilizer every two weeks through the growing season, or a slow-release granular worked into the top inch of soil, supports the dense, floriferous growth most people want.
Which Types Overwinter Best
Not all pelargoniums are equally easy to carry through winter. The common zonal types, the ones with round flower clusters and often a darker “zone” marking on the leaf, are the toughest and most forgiving. They tolerate both the active windowsill method and full dormancy with high success rates. Ivy-leaf trailing types are nearly as tough, though they tend to drop leaves more readily in low light. Regal or Martha Washington pelargoniums are fussier; they need a period of cool temperatures (around 50°F) to set flower buds for the following season, so the dormancy method actually suits them well, but they are more sensitive to overwatering during storage.
Scented-leaf geraniums, prized for aromatic foliage that smells like rose, lemon, mint, or dozens of other things, generally overwinter best as active plants on a bright windowsill. They tend to be woody and slow to recover from hard pruning, so cutting them back drastically for dormancy storage sometimes results in plants that take a long time to fill back out. If you have the light, keep them growing.
Seed-grown geraniums from garden centers, the type sold by the flat as bedding plants, are genetically programmed to peak in one season and can be harder to overwinter than named cultivars propagated from cuttings. They will survive, but the plants are often weaker and less productive in their second year. If you have a favorite color or habit from a seed-grown plant, taking cuttings in late summer and rooting those for winter may give better results than trying to carry the mother plant through dormancy.
Taking Cuttings as Insurance
Even experienced gardeners lose plants over winter. Taking a few cuttings in late summer or early fall acts as a backup. Snip three- to four-inch stem tips just below a leaf node, strip the lower leaves, and stick the cut end into a small pot of moist perlite or a mix of perlite and peat. Geranium cuttings root readily without rooting hormone, though a light dusting does not hurt. Keep them in bright indirect light, mist occasionally, and roots typically form within two to three weeks. Research has confirmed that higher sugar reserves in pelargonium cuttings, driven by cooler rooting temperatures, correlate with stronger root development and better survival.1Postharvest Biology and Technology. Response of post-storage carbohydrate levels in pelargonium cuttings to reduced air temperature during rooting and the relationship with leaf senescence and adventitious root formation A cool bright room, rather than a warm dark one, gives cuttings the best start.
Rooted cuttings take up far less space than full-size plants and are often more vigorous the following spring. If windowsill real estate is limited, overwintering six small cuttings in a single tray beats trying to fit three large pots on the ledge. By May, those cuttings will have grown into compact, well-branched plants ready to fill containers or garden beds.
Soil Health After Repeated Overwintering
If you keep the same geraniums in the same pots year after year, the potting mix gradually breaks down. Organic matter decomposes, drainage slows, and the mix compacts around the roots. Nutrient depletion is part of the problem, but structure loss is just as important. Every spring, when you bring the plants back out, refresh the soil. The simplest approach is to unpot the plant, gently tease apart the outer roots, shake away as much old mix as you can, and repot with fresh potting soil. This also gives you a chance to inspect the root ball for rot, circling roots, or pest larvae.
The microbial community in the soil also changes over time. A freshly mixed potting medium supports different fungal and bacterial populations than a mix that has been through multiple wet-dry cycles in storage.2PubMed Central. Mycorrhizal and Soil Microbiome Dynamics Replacing the mix annually is the easiest way to reset the soil microbiome and reduce the buildup of soilborne pathogens. Some gardeners add a small amount of compost or worm castings to the fresh mix for a microbial boost, which is a reasonable practice though not strictly necessary for geraniums, which are not particularly heavy feeders.
When Overwintering Is Not Worth the Effort
There are situations where buying new plants each spring makes more sense than overwintering. If your only storage option is a warm, dark closet with no airflow, success rates drop sharply. If your indoor environment is chronically overheated and bone-dry from forced-air heating, plants will struggle without constant attention. And if you are growing inexpensive seed-grown bedding geraniums that cost a few dollars per plant at the garden center, the labor of overwintering a dozen of them may not pencil out compared to buying fresh ones.
Where overwintering really pays off is with named cultivars, unusual scented-leaf varieties, or plants you have trained over several years into large specimens. A mature geranium that has been growing for three or four seasons develops a thick woody base and produces dramatically more flowers than a first-year plant. Losing that to a frost when a few minutes of effort in October would have saved it stings in a way that losing a $3 bedding plant does not. The decision is ultimately about what the plant is worth to you, measured in both money and sentimental attachment.