If you have outside Geraniums and want to make sure that these plants make it through the winter and into the next spring and summer, you will need to take certain steps to ensure that they are protected. When choosing how to overwinter Geraniums there are four different options you can consider. The best choice for you will depend upon your resources, the weather where you are in the UK, and the available spaces you have on your property. Below we will look at the top four ways to look after geraniums over winter and detail how you can go about protecting your Geranium plants through the colder months.
Are Geraniums Hardy?
The common Geranium is not a hardy plant but it can decorate your garden for many years as long as they don’t have to deal with extreme cold. If you have true Geraniums in your garden, you will find that they are more winter-hardy and are suitable as garden perennials in colder climates.
So, your first step in deciding how you are going to overwinter Geraniums is to make sure you know which type of Geranium plants you have planted in your garden.
“Geraniums are beautiful plants which add colour and vibrant detail to any landscape. However, they are ill-equipped to survive harsh winter conditions.” Greg Wallace of Iowa State University.
How to Overwinter Geraniums?
Your four options for overwintering Geraniums are to place them in an unheated greenhouse, use a horticultural frost fleece, use bare root storage, or bring them inside the house. Read below to discover which method seems more suitable for your plants.
Note: You will also need to remember to cut the plants back by about two-thirds and also decrease the amount of watering you do through the winter months.
1. Overwinter Geraniums in an Unheated Greenhouse
One of the easiest and most economical ways to look after your geraniums over winter is to place them in a Greenhouse. You simply need to carefully dig up your Geraniums from the soil, (making sure not to damage the roots), and place them in pots. Then you can cut back the plants for the winter.
Step 1 – Prepare Your Geraniums
Begin by carefully digging up your geraniums from the garden. Ensure you handle them gently to avoid damaging the roots.
Step 2 – Pot the Geraniums
Once uprooted, transfer each geranium into a suitable pot with adequate drainage.
Step 3 – Prune for Winter
Trim back the geraniums, removing any excess growth. This prepares them for their dormant winter phase.
Step 4 – Position in the Greenhouse
Move the potted geraniums into your unheated greenhouse. Ensure they are placed in a location where they won’t be directly exposed to frost.
Step 5 – Monitor for Frost
Regularly check the greenhouse to ensure that the geranium stems are not exposed to frost, as this can be detrimental to the plants.
Step 6 – Maintain Throughout Winter
While the geraniums are in the greenhouse, keep an eye on them and ensure they remain frost-free throughout the winter season.
2. Overwinter Geraniums in a Heated Greenhouse
If the weather in the winter includes extreme temperature drops, you can overwinter geraniums in a heated greenhouse. Having a greenhouse heater (Amazon link – opens in a new tab) is a great way to ensure that they are not exposed to freezing temperatures during the winter.
You should be aiming for a temperature of between 7-10°C if possible and they do best at no less than 5°C.
Step 1 – Prepare Your Geraniums
Start by gently digging up your geraniums from their current location, ensuring you don’t damage the roots in the process.
Step 2 – Transfer to Pots
After uprooting, place each geranium into a pot with good drainage.
Step 3 – Trim for Winter
Prune the geraniums by cutting back any unnecessary growth. This helps them better manage the winter months.
Step 4 – Position in the Heated Greenhouse
Relocate the potted geraniums to your heated greenhouse. Choose a spot that ensures even heat distribution for all the plants.
Step 5 – Set the Right Temperature
Adjust the greenhouse’s heating system to maintain a consistent temperature that’s optimal for geraniums. This typically means keeping the environment just warm enough to prevent frost but not so warm that the plants are encouraged to grow actively.
Step 6 – Monitor and Water Sparingly
While they’re in a warmer environment, geraniums will require less water. Monitor the soil moisture and water only when it feels dry to the touch.
Step 7 – Check for Pests
A heated greenhouse can sometimes attract pests. Regularly inspect your geraniums for any signs of pest infestations and treat them as necessary.
3. Overwinter Geraniums (Bare Root Storage)
You can also choose to overwinter Geraniums using bare root storage. Using this method, you will remove them from the ground and store them in a dormant state with no soil surrounding them until you are ready to plant them again in the spring.
Step 1 – Prepare Your Geraniums
Start by carefully digging up your geraniums from the ground, ensuring you don’t damage the roots.
Step 2 – Clean the Roots
Gently shake off and remove as much soil as possible from the roots. There’s no need to wash them but ensure most of the soil is gone.
Step 3 – Prune the Plants
Trim back the geraniums, cutting away any excess growth and dead or yellowing leaves. This will help reduce the risk of mould or rot during storage.
Step 4 – Choose a Suitable Storage Location
Find a cool, dry, and dark place for storage, such as a basement, garage, or garden shed. The ideal temperature range is between 45°F to 50°F (7°C to 10°C).
Step 5 – Store the Geraniums
Place the bare-root geraniums in a cardboard box or paper bag. If using a box, you can layer the geraniums with newspaper or straw to provide some cushioning and absorb any residual moisture.
Step 6 – Monitor the Geraniums
Every few weeks, check on your geraniums. The roots should remain firm. If they begin to shrivel, lightly mist them with water to rehydrate. Remove and discard any parts that show signs of mould or rot.
Step 7 – Re-pot in Spring
As the winter ends and spring approaches, prepare to re-pot the geraniums. Choose fresh potting soil and ensure the pots have good drainage. Plant the geraniums and water them well, placing them in a sunny location to encourage new growth.
4. Overwinter Geraniums by Bringing them Inside
Perhaps the safest way to ensure that your geraniums remain alive throughout the winter is to bring them inside your home.
You can pot the plants up and place them on windowsills around your home so that they remain protected from the cold and rain while being exposed to sunlight. If you bring the flowers indoors you should find that the plants remain flowering throughout the winter months.
When deciding how to best overwinter your geraniums you will find that you have a range of options. Perhaps the most effective way to ensure that your geraniums are protected is to pot them up and bring them inside. But if this isn’t an option you can place the pots in a greenhouse, keep outside potted geraniums warm by using horticultural fleece or put the plants into a dormant state by using bare root storage methods. Follow our tips above and you should find that your geraniums are ready to be planted outside again next spring!
Garden Doctor Tips
“If your geraniums are already potted and you are worried about leaving them out, bring them indoors!”
“When storing geraniums using the bare root method, ensure that the roots are clean and dry to prevent them from rotting!”
“Place your geraniums between layers of newspaper, not only will this protect them, but the paper should absorb any moisture!”
“If keeping your geraniums in a greenhouse, depending on the weather, it may be worth getting a heater to keep the temperature above freezing!”
Frequently Asked Questions
Can geraniums survive outside in winter?
Yes, but only if you live in a mild climate. Geraniums will survive a light frost, but a hard freeze will kill them. If you live in an area where the temperature dips below freezing, you will need to take measures to protect them.
How do you keep geraniums through the winter?
There are a few ways to keep geraniums alive through the winter. One option is to keep them inside near a sunny window. Another option is to move them to a greenhouse, where they will be protected from the cold weather. Finally, you can wrap them in fleece or some other type of insulation to protect them from the cold.
Do geraniums need to be brought inside for the winter?
If you live in a cold climate with harsh winters, it’s best to bring them inside for the winter. If you have a heated greenhouse, that would be the best place for them. If not, then you can wrap them with fleece and keep them in a warm room. Make sure the soil is moist, but not wet.
Trevor Wright is not just a seasoned horticulturist; he’s the esteemed Garden Doctor. With a BSc in Horticulture and years of hands-on experience in the soil, Trevor has become a trusted mentor for all things gardening. As the founder of Garden Doctor, he’s committed to clarifying the intricacies of gardening, offering straightforward advice that’s rooted in years of practice. His writing is a garden of how-tos, savvy insights, and comprehensive guides that enable individuals to nurture and grow their garden dreams. When he’s not knee-deep in garden beds, Trevor is at his keyboard passing on his green-thumbed wisdom to budding gardeners, ensuring that the legacy of sustainable and joyful gardening blossoms far and wide.