Red ginger plants (Alpinia purpurata) are tropical, perennial flowering plants that are native to the South Pacific. They are grown for their foliage and striking 6-to-12-inch spike-like columns with clusters of small, bright-red flowers, which make excellent cut flower arrangements. Red ginger grows from a root cutting that is divided from the rhizomous root system.
Dig up the red ginger plant carefully to obtain cuttings from the rhizomous root system. Start digging at least 6 to 8 inches away from the plant to avoid severing any of its root system with the shovel. If you have already obtained the root cuttings, proceed to step 3 below.
Shake off the clumps of roots to remove excess soil. Divide the clumps of roots into 3 or 4 smaller sections. Separate the roots to make sure they are not matted or knotted together. They should pull apart easily; if not, sever them using a pair of garden snips.
Place the individual root cuttings onto a sheet of newspaper. Carefully dust each root cutting with a light dusting of powdered rooting hormone with a fungicide, or just a powdered fungicide. (You can purchase a rooting hormone with fungicide at a plant nursery or garden center).
Fill 6-inch plastic pots about 1/2 full with vermiculite or any good-quality sterilized potting mix that contains perlite (or peat moss) and sand. Dampen the growing media until it feels moist to the touch.
Set one red ginger plant root cutting into each 6-inch pot. Add approximately 2 inches of either the vermiculite or the potting mix to each pot.
Set a drainage dish under each pot to help increase humidity and facilitate drainage. Place a shallow layer of pea gravel into the bottom of each dish.
Transfer the 6-inch pots to a bright. warm location. The temperature must remain at 50 degrees F (or above) at night. Provide as much light as possible, but not direct sunshine, a minimum of eight hours a day. Keep the soil moist, but avoid overwatering. Fertilize every week using a water-soluble 1-1-1- or 3-1-5 fertilizer until the plants are established. Then plan on fertilizing the red ginger plants about once a month. Red ginger plants will typically become established between six and twelve months after cuttings are taken.