I bring my geraniums inside and grow them all winter and I've been doing this for more years than I care to remember. They soon become accustomed to the lower light. All the leaves that were on the plant outside will yellow and die off but new leaves take their place. If you give them a south or west facing window they do fine and grow well.

I remove flower buds as they form. I want their nutrients to go to new branches not flowers. When it gets a long shoot I cut it back and start a new plant from the cutting.

In late february I take cuttings from each plant and trim them into nicely shaped plants. The cuttings go on newspaper for 5 days to callus over and then are planted in soilless mix. Then both the plants and cuttings go under my fluorescent lights. In early May they go outside in my cold frame--after hardening off and are planted in the flower beds and pots in late may.

In all the years I've been doing this I have only lost 2 mother plants and there may have been something wrong with them when I brought them in. Geraniums are not very fussy plants. The Victorians used them as houseplants because they tolerated the coolness of fireplace heated homes and the lower light of winter

I have 3 huge plants that I would like to over winter. Do I need to repot in fresh potting soil now. If not, do I have to worry about bringing bugs into my home? I had them on my deck in containers.

As with many plants we leave out of doors and wishing to take them back indoors at end of season it is a good idea to do a serious examination of them so that the bugs are not given a nice place to breed.
A day or so in the garage or shed to allow them to dry out should be considered. Whether you think a spraying of an insecticide is necessary is up to you; sometimes a bit of finger brushing can often sight bugs that can be plucked off and washed down the drain.
bigger plants, such as hibiscus, should be examined carefully and allowed to sit in the garage where it can be covered with a bag which envelopes it completely, then a spray can be given it to completely affect the whole plant, left for a day, then re-examined before taking it indoors to a sunny window.
This is done when outside temperatures begin to fall below 40úF.
Often it is taken indoors and put back out when daytime temperatures rebound.
Geranium must not ever be affected by a killing frost--it destroys their ability to come back.

The geranium plant, even the big ones, can be removed from their pot, the soil from their roots shaken off....no need to wash--left in the garage for a day or so, then taken directly to the coolest area of the basement where it sits....undisturbed--no water, no light, no heat...until about mid February through mid March...when the above methods are carried out.
In the basement, whether you hang them up (upside down is the easiest) or just leave them in their pots to completely dry out, is up to you.
With any hung up plant, expect to have to clean up debris of falling dried out leaves, dried out soil and any flowers you've left on. For this you can place them then in a paper bag....no plastic, it doesn't breathe....which catches the debris. DO NOT tie the bag closed...leave them open so that air can circulate. Do not water them...not even a sprinkle...let them dry out completely.

When you bring them out, remove any old blooms, remove any damaged or recently developed stems, any old leaves hanging on, and cut them back to what you feel is wanted to re-plant. Cutting it back by a third or more is perfectly alright...the plant will resume its former self from how its strength was there before.

Where you feel the size of the plant is large...maybe too large for you to handle, then consider dividing it into as many smaller plants as you feel necessary.
Simply find the easiest method to untangle the roots while at the same time, tearing it apart to form new plants.

Don't try to re-use the old soil---its done its job, throw it into the compost or spread it on the lawn. Give your new plants fresh, good quality, potting soil--do not ever use garden soil for potted plants.
Garden soil has too many bugs for any tender potted plant to fight.

Thanks so much for the info. I have used your method in the past and have had great success.

This was the third winter I've stored my geraniums bare-root in a box in the basement. The previous two winters I had them in a friend's 50 degree basement, but this time they were in my 65+ degree basement. I was concerned that might be too warm, but my plants sailed through winter better than ever. Most of the eight plants barely died back at all. I had to significantly cut back a lot of healthy green stems and roots to get the plants small enough to pot up in the usual 4" pots. No doubt it helped that my plants are two to three years old and have thick stems that hold their moisture easily. I potted up six plants six days ago and all six are already putting out growth from many nodes.

It has been two weeks since I potted up six dormant bare-root geraniums and all six are covered with green. The last two years they regrew at different rates - a couple would grow quickly, a couple others would be slower, and a couple would really lag - but this time they are all growing at the same very fast rate. They are going to look great this year.