To winterize geraniums in a cabin, dig them up before the first frost, trim off dead leaves and flowers, shake off excess soil, and store them upside down in a paper bag or cardboard box. Place the container in a cool, dark, and dry spot, ideally between (45^{circ }F) and (60^{circ }F) ((7-14^{circ }C)), and check every few weeks for mold or excessive dryness. In late winter or early spring, remove any rotten parts, pot them, and place them in a bright window to reawaken them for the next season

Re-Plant Overwintered Geraniums: Easy 3-Steps

How To Overwinter Geraniums