There are several ways to care for your Geraniums during winter, and even if many people believe that Geraniums have to rest during winter it's actually not true, at least not for the majority of them. In fact, the only ones that have to rest are the ones that naturally go into dormancy or the ones that start losing their leaves as the summer months come to an end (this is most common with some hybrids). But for the rest of them: they can actually keep blooming through the winter and don't need any dormancy at all.
But is there a simple way to overwinter your Geraniums that will suit most of them? Yes:
Place your plant in a spot with 10-20 °C / 50-68 °F. It might be easier for them to survive if the temperature is on the lower end of the temperature spectrum, even if normal room temperature should also work for most of them.
Use a grow light if you don't have a spot that's bright enough (higher temperature = more light = more water, and therefore also lower temperature = can handle less light = doesn't need that much water at all). But a general tip: it's more common to place them somewhere too dark than the opposite.
Want the full list on how to overwinter your Geraniums? Keep reading!
Check the soil Before moving your plant from where it has been during spring / summer, make sure the soil is dry to avoid mold growth.
Check for pests When your plant is moved to a new location and proceeds into the winter months, it might get a bit weak. Its normal resilience against pests is therefore lower. Make sure to check that your plant is healthy and free of pests before moving it to its winter location.
Keep an eye on the temperature Suitable locations for Geraniums during winter can be in the garage, shed, basement, attic, summerhouse or a cool stairway if you are living in an apartment. But you can also keep it at normal room temperature as stated earlier. Recommended temperature for this plant:
Add extra grow light Pick a full-spectrum light bulb and place it 20-30 cm / 8-12 inches above the plant to prevent leaf burn. Keep the light on for 14-16 hours / day.
Reduce watering Cutting back on watering during winter is key to help your Geraniums to survive. The amount of water it will need will depend on the amount of light it will get and what temperature it's placed in. But in general: it's better to water it a bit too little during winter than a bit too much (since it's easier for them to survive drought than too much water).
Keep an eye on it Keep checking your Geranium from time to time to be able to stop any infestations at an early stage. It's also important to know that it's not normal for most Geraniums to drop too many leaves during winter, so if yours start shedding: something is going on! The most common causes are too much or too little water, too little light and too high temperatures. So, check the soil and the roots and make sure that everything is okay regarding the amount of light and temperature conditions.
“Just because your Geraniums don't need watering that often during winter, it doesn't mean that they want to be drenched each time either - it's actually better to just give them a small amount instead of too much." — PLANTA TIPS