How Do You Keep Geraniums Over the Winter?
The cold, dark months of winter can be devastating to geraniums. But you can still have some success in growing them, so long as you take the right steps to prepare your plants.
Bringing them indoors during the fall is an easy way to keep geraniums alive and healthy. Just make sure you bring them inside before the first frost and place them near a sunny window or under grow lights.
You can also overwinter geraniums from the garden in a greenhouse or conservatory. This is an excellent option for those of us who live in regions where the temperature drops too low to overwinter in our backyards or garden beds.
It’s also worth checking to see if your geraniums are healthy and disease free, says David Taylor of the UK Pelargonium and Geranium Society (opens in new tab). Check the stems for signs of fungus, such as rust or mildew. If they’re rusty, you may need to spray them with a fungicide.
When you’re ready to bring your geraniums outside, prune them back before putting them in the ground or moving them from their winter home into their spring planting location. This will reduce their load on the plant’s roots and stems, which will allow them to store more energy for a strong spring.
To do this, trim back the flowers and flower stems to a third of their length and leave a few inches of green growth on each stem. This will encourage the plant to form a nice shape and produce more blossoms in the spring.
Once you’re finished pruning, repot them and give them some light in the winter. You can put them in a container filled with premoistened potting mix that is designed for flowering plants, and tuck the stems deep enough to leave two leaf nodes above the mix.
Then water them well and store in a cool place with good air circulation, such as an unheated bedroom or an indoor porch. You can also hang them upside down in a basement, garage or other spot that stays at least 50 degrees F. Once a month, soak the roots in water for an hour and re-hang them.
This method works best with zonal geraniums, but many others will also work as long as the stems are firm. You can hang the geraniums or place them in paper bags, but be sure to not seal them tightly as this will restrict air flow and potentially cause mold to develop on the geraniums’ leaves.
You should also inspect the plants for worms and other insects that might attack them during winter. If you see any pests, remove them from the plants before storing them.
To avoid mold, rot and other diseases, remove leaves or entire flowers that appear to have a white or brown tinge to them. Any geranium that shows signs of pests or diseases should be disposed of.
Another way to overwinter geraniums is by digging them up and storing them in a dormant state. This is an excellent choice for zoned geraniums, but other varieties might not perform well in this method, especially if the plants are stored in the basement or other unheated locations that are too dry and warm to retain their dormant state.