Choose a pot that has holes in the bottom for drainage. The appropriate pot size allows for 1 inch between the root ball and the inside wall of the pot.
Inspect the geranium's stems when you remove them from storage. If they appear shriveled or otherwise unhealthy, discard the plant. It's normal for the tip of the stem to die back.
Use sharp scissors or snips to cut the stem tips until all the discolored portions are removed. Then cut the entire geranium back to one-third its size.
Place the geranium's roots in a container of water while you prepare the pots.
Fill the new pot, three-fourths full, with fresh potting soil. Place the geranium's roots on the soil in the pot and finish filling the pot with soil, to within 1 inch of the rim, pressing lightly on the surface when you finish.
Water the soil slowly until water seeps from the bottom of the geranium's pot and place the pot in a sunny area. It may take several weeks until you see new growth.