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How to overwinter geraniums – grow indoors, let them go dormant or take cuttings
Last Updated on June 28, 2019 by John
If you have a beautiful geranium in the spring, there’s no reason why you can’t store them for the winter and keep it going without having to start over the following season. Overwintering your geraniums don’t take a lot of space nor does it require a lot of time or money invested.
It is important to have realistic expectations going in though. The longer you keep your geranium alive, the woody or the stems become and as that happens you see a decrease in flowering. However, they do acquire a very unique shape about them reminiscence of a Bonsai tree. As long as you are willing to forego some of the extra blooms and you invest in some pruning to promote new growth and get extra flowers, you can successfully overwinter your geraniums.
There are 3 ways to deal with geraniums over winter, firstly you can bring them indoors and they will usually continue to grow and may even flower, second you can cut them back hard for winter and store them in a greenhouse over winter but they may need a little heat to stop them frost getting on the stems or you can take a few cutting and start with new plants. Below we go over these 3 steps in more detail.
Growing geraniums indoors
Knowing how to make your geraniums survive the winter starts with bringing them inside. They can fare very well inside if they get lots of bright light. They prefer cooler temperatures though so it’s best to put them in a window where they are not close enough to get a draft but the area does stay cool and get ample sunlight.
To do this over the winter time you want to bring your geraniums inside before your first frost. The reason for this is that you want to expose the plants to the indoor temperatures so that they can adjust to the change in humidity and the environmental changes brought about by central heating. Consider that when you transplant flowers outside you need to harden them off, give them some exposure in small doses to the outside elements. When you overwinter your geraniums you’re doing effectively the same thing but in reverse, preparing them for the indoor conditions, also the frost will kill geraniums.
Be sure to check your plants regularly for any signs of disease or insects. Once that is done you should dig them up if they are outside and put them in a pot after you prune them back by about one-third. Long-term this type of pruning will help them to survive the winter and replenish themselves in springtime. After this is done you want to water thoroughly the first time you bring them inside but they’re after you want to allow the soil the opportunity to dry out before you water again. In order to keep your geraniums blooming more frequently, you need to give it a little drought stress. Some gardeners disagree with this and will recommend you keep the soil moist but not wet. This is something you can try and see what works best for you. What most people do agree on is they need good air ventilation and prefer a more dry atmosphere, this is help stop them from going mouldy and starting to rot.
As it lives indoors keep your eyes peeled for fungus gnats, aphids, and spider mites. So long as your plant remains happy it may bloom very well and you can move it back outside come springtime or let it stay where it is adding flowers to your indoor environment.
How to make geraniums go dormant for the winter
If you have a full-sized geranium you can make it go dormant for the winter which basically means its stopes growing and using energy and then it comes back come springtime with the warmer temperatures. If you are going to make your geranium go dormant you want a cool, unheated space in which to store it usually a cool dry space such as a greenhouse or shed. The area where the plants are stored needs to remain cold but it can’t get below freezing if you keep in it a greenhouse its best to have a heater with a thermostat set to around 5ºdeg;C or 41ºdeg;F to keep the frost at bay.
To do the successfully, you want to take your geraniums out of the pot and allow the soil to dry out. You should cut the plant back so that it’s half the original size and then top each of your geraniums with a paper bag. Place the bag in a cool dry area or other cool location you have selected and check on it every few weeks just to make sure it has not fully dried out. If it has you can simply spray the root area with some water and then put the paper bag back over it.
About six weeks prior to springtime, right before your last frost date, you want to bring the geraniums back so that they get indirect light. If you stored them with bare roots you want to pot them first after you have soaked the roots to rehydrate them. It’s recommended at this point that you give them a half the recommended rate of concentrate of plant feed and thoroughly water them once they are potted so that they can slowly come out of dormancy. If you plan to move them outside do not make the manoeuvre until all danger of frost is over, in the UK the end of May is usually about the right time.
Taking geranium cutting for the following year
You can always overwinter your geraniums by taking cuttings and its an excellent way to start the year with fresh new plants in spring. Cuttings are a more effective way to keep a plant you already love without the risk of your geranium losing its floriferous qualities. More importantly, these small plants take up less space and they’ll provide you with more blooms throughout the subsequent seasons.
When making your cuttings, you want to cut from a healthy plant and then allow those cuttings to sit overnight. The next day you will notice that the end where you cut produced a callus and that’s actually going to help your geranium to root.
When you are ready to place the cuttings inside your containers and after about one month you may start to see some root growth, once they have established a good root system, you can pot them and grow them either as houseplants or move them outside once the risk of frost has passed.