Geraniums are one of those plants that bring color, charm, and a cheerful vibe to gardens, patios, and windowsills.
I’ve always loved growing geraniums because of how easygoing and resilient they are, but as winter approaches, especially in colder climates, they do need a little extra care to ensure they make it through to spring.
September is a critical time to start preparing your geraniums for winter survival.
Whether you plan to overwinter them indoors, cut them back, or leave them outside in warmer climates, the steps you take now will determine how well they fare during the colder months.
I’ve learned through trial and error what works best, and I’m excited to share those tips with you to help your geraniums survive—and even thrive—when winter sets in.
Assess the Climate First
Before doing anything, it’s important to assess your climate and understand how cold your winters typically get.
In mild climates, where frost is rare, you might be able to leave your geraniums outside with some protection.
However, in areas with freezing temperatures, your geraniums will need to come indoors or be carefully stored for winter.
Where I live, winters can get quite cold, so I always plan ahead and decide in September whether I’m bringing my geraniums inside or storing them in a dormant state.
Take a look at the USDA Hardiness Zone for your area if you’re unsure.
If you’re in Zone 9 or above, you can likely leave your geraniums outside year-round with some winter protection.
In colder zones, you’ll need to dig them up or bring potted geraniums indoors to keep them alive through winter.
Once you know your climate, you can plan your next steps accordingly.
Clean Up the Plant
One of the first things I do in September is clean up my geraniums.
After a long summer of growth, they can become a little unruly.
This is the perfect time to trim off any dead, yellowing, or damaged leaves to tidy up the plant.
I’ve found that starting with a clean, healthy plant makes overwintering much easier.
Using sharp, clean pruning shears, I remove any leaves that look faded or unhealthy.
Be sure to also cut off any spent blooms or flower stalks that have finished their cycle.
Cleaning up the plant reduces the risk of pests and diseases, which is especially important if you plan to bring your geraniums indoors.
I always give my plants a good once-over to ensure they’re in top shape before the cold sets in.
Cut Back Leggy Stems
If your geraniums have become leggy over the summer—which happens frequently, especially if they’re in a crowded spot or competing for light—September is the perfect time to cut them back.
I often find that my geraniums can look a bit wild by the end of the season, with long, stretched-out stems that aren’t as full as they were in the spring.
To fix this, I cut back the leggy stems by about one-third to one-half.
Don’t be afraid to be a little bold here—geraniums are hardy, and pruning encourages them to grow back bushier and healthier.
Make your cuts just above a leaf node to encourage new growth from that point.
Cutting back in September also makes the plant more manageable if you’re planning to bring it indoors, and it reduces the amount of space it will take up in storage.
In my experience, pruning geraniums back in the fall gives them a head start in the spring.
By the time warmer weather returns, they’ll already have new, compact growth and will be ready to bloom again.
Decide How You’ll Overwinter Them
There are a few different methods for overwintering geraniums, and the one you choose depends on your climate, space, and how much care you’re willing to give them over the winter.
You can either bring them indoors as houseplants, store them dormant, or in some climates, protect them outside.
Overwintering Indoors as Houseplants:
If you have space inside and want to enjoy your geraniums throughout the winter, you can bring them indoors.
I’ve done this with my favorite potted geraniums, and they usually keep blooming if given enough light.
Place them in a sunny window where they’ll get plenty of light—geraniums need at least four hours of direct sunlight each day to keep producing flowers indoors.
Water sparingly over the winter, as they don’t need as much water when they’re not in active growth.
Be careful not to overwater, as this can lead to root rot.
I usually water my indoor geraniums about once a week or whenever the soil feels dry to the touch.
Storing Dormant Geraniums:
Another option is to let your geraniums go dormant for the winter.
This is a great method if you don’t have space indoors or if you have a lot of geraniums to store.
To do this, dig up your garden-grown geraniums in September and shake off the excess soil from the roots.
Then, place the entire plant upside down in a cool, dark, and dry place, such as a basement, garage, or unheated shed.
If you’re storing potted geraniums, you can leave them in their pots but stop watering them once they’ve entered dormancy.
Check on your stored geraniums every month or so to make sure they’re not too dry—if the roots feel too brittle, mist them lightly with water.
In the spring, around March or April, you can bring your dormant geraniums back into the light and start watering them again.
After a couple of weeks, they’ll begin to sprout new growth and will be ready to replant in the garden.
Reduce Watering
As the days shorten and temperatures cool, geraniums naturally slow down their growth, which means they require less water.
In September, I gradually reduce the amount of water I give my geraniums to help them transition into dormancy.
Overwatering at this time of year can lead to root rot, especially if you plan to bring them indoors or store them dormant.
If you’re overwintering your geraniums as houseplants, cut back on watering and allow the soil to dry out between waterings.
For plants you’re preparing to store dormant, stop watering completely once you’ve cut them back and are ready to move them into storage.
In my own experience, getting the watering schedule right in September is crucial for keeping geraniums healthy through the winter.
Too much water can be just as harmful as not enough, so it’s important to strike the right balance.
Check for Pests
Before bringing your geraniums indoors or storing them for the winter, it’s important to check for pests.
Geraniums can sometimes attract aphids, spider mites, or whiteflies, and you don’t want to bring these pests inside or allow them to overwinter with your plants.
I always inspect the leaves and stems closely for any signs of pests, like tiny insects or discolored spots.
If I notice any pests, I treat the plant with insecticidal soap or neem oil to get rid of them before moving the geraniums indoors.
If you’re overwintering your geraniums indoors, quarantine them for a couple of weeks in a separate room from your other houseplants to ensure that no pests hitch a ride inside.
In my experience, catching pests early can save you a lot of trouble later in the winter when you’re trying to manage multiple plants indoors.
Apply a Light Fertilizer
While you don’t want to encourage too much growth in September, applying a light fertilizer can give your geraniums a boost before they go dormant or are brought indoors.
I like to use a balanced, slow-release fertilizer at this time to help strengthen the plant’s roots for the winter ahead.
If you’re bringing your geraniums indoors, a light feeding will keep them looking healthy and might even encourage a few more blooms throughout the winter.
If you’re storing them dormant, the fertilizer helps prepare them for a strong start in the spring when they begin growing again.
Avoid using high-nitrogen fertilizers in September, as this can encourage leafy growth that won’t have time to harden off before the first frost.
Instead, opt for a balanced or low-nitrogen formula to promote root health.
Mulch Outdoor Geraniums
If you live in a mild climate where winters don’t typically dip below freezing, you may be able to leave your geraniums outdoors with some added protection.
In these cases, adding a thick layer of mulch around the base of the plants in September can help insulate the roots and protect them from light frost.
I’ve found that straw, shredded leaves, or bark mulch works well for this purpose.
Apply the mulch 2-3 inches thick around the base of the plant, but be sure to leave a little space around the stems to prevent rot.
Mulching also helps retain soil moisture and keeps the temperature more consistent, which is especially important during the fluctuating temperatures of early fall.
Bring Potted Geraniums Indoors
If you’ve grown your geraniums in pots, September is the time to bring them indoors before the first frost hits.
Potted geraniums are more vulnerable to cold weather because their roots are above ground, so they can freeze more easily than garden-grown plants.
Before bringing your pots inside, give them a good cleaning to remove any dirt, pests, or debris.
I also prune the plants back by about one-third to make them more manageable indoors.
Place them in a sunny spot where they’ll get plenty of light—geraniums need at least four hours of direct sunlight each day to stay healthy indoors.
If you don’t have a bright enough spot, you might want to consider using a grow light to supplement their light needs.
In my experience, keeping geraniums near a south-facing window works best, but a grow light can be a lifesaver if natural light is limited.
Monitor Throughout the Winter
Once your geraniums are indoors or stored for the winter, it’s important to monitor them regularly.
Check for signs of pests or disease, especially if they’re being kept indoors.
If you’re storing dormant geraniums, inspect them every month or so to ensure they’re not drying out too much or showing signs of mold.
For indoor geraniums, make sure to rotate the pots regularly so they get even sunlight on all sides.
Keep an eye on the watering schedule, and adjust based on how much the plant is growing.
I’ve found that geraniums don’t need much attention over the winter, but keeping a close watch will help ensure they stay healthy and ready for spring.
Prepare for Spring
By the time March or April rolls around, it’s time to start thinking about reintroducing your geraniums to the outdoors.
If you’ve kept them indoors, gradually move them outside to acclimate them to the cooler spring temperatures.
For dormant plants, bring them out of storage, give them a light watering, and place them in a sunny spot to encourage new growth.
In my experience, geraniums bounce back quickly once they’ve had time to adjust to the new season.
By the time warmer weather arrives, they’ll be ready to put on a fresh display of blooms.
Final Thoughts
Taking the time to properly care for your geraniums in September is essential for ensuring they survive the winter and come back strong in the spring.
Whether you’re bringing them indoors, storing them dormant, or protecting them outdoors, a little extra effort now will go a long way.
Through years of growing geraniums, I’ve found that September is the perfect time to prepare them for winter survival.
With the right care, your geraniums will reward you with healthy growth and vibrant blooms year after year.
Happy gardening!