Cuttings can be rooted in vermiculite, perlite, coarse sand, mixtures of sand or perlite with peat moss, or any other material that will support them, while remaining loose enough to allow air to reach newly forming roots. The material should hold enough water to prevent the lower end of the stem from drying, and it should also be free of insects and disease-causing organisms. Plants, such as gardenias, that prefer acid soil often root better in a mixture containing peat moss in addition to sand or perlite. Water is not a good medium to root most cuttings in because an adequate amount of oxygen can't reach developing roots. You'll get a sturdier root system if you use another rooting medium. Some very succulent plants such as coleus and mints, and some vining houseplants as swedish ivy, ivies, or philodendrons will root readily in water.
Place the rooting medium in a container, such as a flower pot, and settle in gently by tapping. Don't pack it down hard. Then insert the cuttings into holes made with a pencil, taking care not to crowd them too closely. Dusting the bases of cuttings, prior to sticking, with rooting hormone powder may increase your success with some hard-to-root kinds of plants, but many kinds of houseplants and herbaceous plants (annuals, perennials) will root satisfactorily without this treatment. Leaves of adjacent plants should just overlap. Water thoroughly to settle the rooting medium around the cuttings and hold them in place.
After inserting the cuttings into the rooting medium, place a polyethylene bag over the entire pot and fasten it tightly around the base. You may wish to support the bag above the cuttings with straws or small stakes. This bag helps maintain optimum moisture conditions for rooting cuttings. Place the pot where it will receive plenty of diffuse light, but no direct sunlight. A north- or east-facing window is a good choice, especially in warm, bright weather. Open the bag every day for a few minutes to allow fresh air to reach the cuttings and to prevent mold from forming.
Check the temperature near the window to make sure it doesn't drop below 55 or 60 degrees F at night. The cuttings will root faster if temperatures are 65 to 75 degrees F. It is not usually necessary to water the cuttings again for about 2 weeks. But check them periodically to make sure the "soil" doesn't become dry. The length of time needed for roots to form depends on the kind of plant, the temperature, and other factors. Many kinds of houseplants, coleus and such will root in 10 to 21 days.
How To Preserve Flowers