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How to Overwinter a Geranium
Today’s post is thanks to a reader who recently sent in an important question: how do you overwinter a geranium?
I mentioned bringing in plants for the winter in the winterizing your garden post, but I didn’t really go into detail beyond “well, you bring them in, and then you take care of them.” I realize that’s a little vague!
So for this post, I wanted to cover exactly HOW to overwinter a geranium.
Getting Started
Choosing the best overwintering method begins with deciding what you want from your geranium. Do you want to continue to enjoy it as an indoor plant, or just save it in an almost bulb-like state? Or do you want to create a new plant altogether?
When deciding what to do, it’s also helpful to know what type of geranium you have. My suggestions here are mostly for zonal geraniums, which are the most common ones most people pick up from a greenhouse every year. You can overwinter any type, but only zonals can bloom year-round. The rest should have a dormancy period.
#1: Overwintering Your Outdoor Geranium as an Indoor Plant
This is the one I have the most experience with… and I also think it’s the best! As long as you have a sunny door or window you can put the geranium near, you can pull this off.
Before bringing your geranium indoors, you may want to prune it to promote health and growth. Here are tips on how to cut them back. Also, check the plants for disease or damage. If they’re free of issues, continue to the steps below.
Transitioning a Potted Geranium
This one is the easiest of all, and it’s what we’ve done with our red zonal geranium for years. Simply bring your potted geranium inside the house on nights it’s supposed to be frosty, and gradually increase the amount of time it spends inside. By a week or two, it should be able to live inside full-time.
Follow the tips on indoor geranium care below to keep it happy all winter long.
When it’s warm enough in the spring, you can start setting the pot back outside during the day. Gradually increase the time it spends outside until it’s outdoors full-time again. In fall, you can start the process all over!
Of course, if you want to make it a permanent indoor plant, that’s fine too – just keep watering and caring for the geranium as usual.
Transitioning an In-Ground Geranium
If you have a geranium you’ve planted in your garden or flower bed, you can simply dig the plant up and repot it for the winter.
Start by gathering a good-sized pot, soil, and a shovel/trowel and some gloves. Make sure you use a high-quality potting soil rather than soil from the garden – even though the plant is already used to the garden’s soil, it doesn’t have enough draining ability or nutrients to support the plant in its new pot.
Carefully dig around the geranium, leaving plenty of room for the roots so they don’t get cut. Pull it out of the ground gently. Replant the geranium carefully in the pot and potting soil.
Water your newly potted geranium well and bring it inside, or, to help it adjust, leave it outside and slowly acclimate it to the indoors by following the steps below.
Tips: How to Care for Geraniums Indoors in the Winter
Make sure your geranium has a sunny window or doorway to live near. Your geranium won’t mind a little cold, as long as it’s not close to freezing. We keep ours in front of south-facing sliding glass doors so the plant gets plenty of light.
Geraniums can be a little fussy when it comes to watering – too much and they rot and die, too little and they wither. In the end, it’s usually easier to bring them back from too little watering than too much, so err on the side of underwatering.
I generally give ours about half a cup once a week, but if your house is more humid, you may need to give it less. Keep an eye and a finger on the soil, and if it’s clearly dry, give it a drink.
Want to watch it bloom all year long? Consider pouring a little bit of diluted coffee on your plant once every week or two. Some people use coffee grounds, but there seems to be a lot of debate over whether the grounds help or hinder them. We just pour about a quarter cup of watered-down coffee on it once every couple of weeks, usually instead of that week’s watering. It always seems to bloom year-round!
#2: Root Storing Your Geranium
If you don’t want to overwinter your geranium in a pot and have a fairly humid, cool area to store it in, root storing your geranium can be an excellent option.
First, use a shovel or trowel to carefully dig up your geranium. You don’t need to shake much of the dirt off, in fact, leaving it on can help protect the geranium’s roots during storage. Store the geranium in a paper bag or wrap the roots in newspaper until spring. You can keep it in your basement, root cellar, or any other area that is moist, dark, and remains between 40-60 degrees regularly.
If you’re not sure if your storage area is damp enough, check the roots once a month to make sure they haven’t completely dried out. If they have, mist them with a little bit of water.
In March, take the geranium out of the bag or newspaper and plant it in a pot. Begin giving it just a little water at first, then increase the amount as the plant begins greening up. By May or June, it should be ready to plant outside again.
#3: Cutting and Starting New Geranium Plants
This final method works well if you’d like to grow some new geraniums, rather than solely preserve your old plant.
Cutting is actually the most common way to propagate zonal geraniums – some are not designed to produce seeds at all, and instead put all their effort into flowering. By using this overwintering method, you’ll actually be doing what your local greenhouse does all the time!
To start, simply cut the last 3-4 inches of a stem with a sharp knife. Pull off any leaves that may be on the lower half. Then place the open, cut area into a rooting hormone.
Place the cutting in well-watered perlite or vermiculite. Keep the new plant warm and moist by keeping it in a greenhouse-like environment. The easiest way is to put a clear plastic bag over it in a warm area with indirect sunlight.
Once the roots are about an inch long (which can take a couple of months), you can transplant the cutting into a regular pot and potting soil. Continue watering as necessary, and place the pot in a bright, sunny location.
Once it has grown to a standard greenhouse size, you can plant it wherever you like – in a pot indoors, or, if it’s May or June, outside in a pot or the garden.
You Can Now Overwinter Your Geranium Successfully!
Regardless of what method you choose, you should now be able to enjoy your geranium for many more summers to come.
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