Prepare the grow tray by filling it with the potting soil and misting the soil until it is damp, never soggy. Poke holes 2 to 3 inches deep in the soil with a pencil. Make the spacing between the holes uniform so many cuttings can fit into the tray.
Pour 2 to 3 tbsp. of the rooting hormone into a clean tray or cup. The cuttings do not require much of the rooting compound, and portioning out from the original container keeps bacteria from entering the bottle and possibly contaminating future plant cuttings.
Choose healthy plants to propagate. Clip 6 inches of soft wood cuttings from the host plant. Generally, soft wood cuttings are clippings made from the summer's growth. New growth still contains too much water and has not hardened off, so instead of rooting, the clippings rot.
Strip the bottom leaves off the plant cuttings, exposing 2 to 3 inches of the stem of the cutting. Keep the top leaves on the stem so photosynthesis occurs while caring for the cuttings and they grow a healthy root system.
Dip the bare stems into the tray with the rooting compound, and stick the cuttings into the holes of the growing tray. Gently pat the soil in place around the plant cuttings to release any air pockets that may have formed. Air pockets in the soil breed harmful bacteria that kills plant cuttings.
Cover the growing tray with clear plastic to form a simple greenhouse effect. Place the growing tray in a sunny location, but avoid direct sunlight. The heat generated by the sun will kill the tender cuttings.
Ventilate the tray once a day by removing the plastic for an hour. Spray with the mister only if the soil appears dry. The cuttings need water but will drown in soggy soil. Remove any cuttings that appear to have died or developed mold.
Watch for new growth after three to six weeks. Remove the plastic when the new growth appears. New growth signals the root system is developing. Keep misting the new plants for about another week, and then transplant them into separate containers. Transplant outdoors in the flower bed once the plant cuttings have reached the desired size.