It’s always sad to know that when summer comes to a close, your gorgeous geraniums will be killed back by the cold weather soon to arrive. But you can console yourself by propagating them so that they'll live on. Just take some cuttings from your plants before frost threatens to kill them back. They’re easy to root and grow, and you’ll be rewarded with lush, thriving geraniums long before your neighbors are able to obtain any next spring. The bonus is that you won’t be spending anything for yours.
Take 4- to 5-inch stem cuttings from your healthy, actively growing geraniums well before frost is predicted for your location. Choose four young, soft stems with new shoots at their tips. Cut off all the leaves from the lower half of each stem.
Mix equal parts coarse sand and peat moss to make the rooting medium and fill a 6-inch pot to ½ inch from the rim with it. Poke four holes 2 inches deep in the medium, evenly spaced apart and about 1 inch in from the rim of the pot.
Dampen the bottom ¼ inch of the stems with distilled water and dip them into rooting hormone. It’s best to use distilled water while rooting cuttings because it contains none of the impurities of ordinary tap water. Plant the cuttings in the holes you made in the potting medium.
Water your cuttings thoroughly to moisten the surface of the medium so that it’s evenly moist, but not soggy. Don’t water again until it has dried out slightly.
Seal the potted cuttings in a clear plastic bag, and poke a few holes in it to facilitate air circulation. Set them in a cool, brightly lit spot near a window, but out of direct sunlight. They‘ll do best in daytime temperature of around 60 degrees F, and begin to develop root systems in about 4 to 8 weeks.
Check the cuttings every 2 to 3 days, and water only when the medium feels dry to your touch. When the cuttings have rooted you’ll begin to notice that they’re growing. Remove the plastic bag.
Move each cutting to its own 4-inch pot, using the same medium mix that you rooted them in. Water enough to moisten the surface evenly and set them in the sunniest spot in your home. Begin feeding an all-purpose liquid fertilizer per the packaging instructions. The young geranium plants prefer 60-degree F daytime temperatures, and will do best if they’re kept at about 55 to 60 degrees F at night.
Plant the geraniums outside in a sunny, well-draining location outdoors after all danger of frost has passed.