Turmeric is a slow-growing edible rhizome from the tropics and looks like a long and thin tuber. This fresh root (or dried and ground) is a flavourful yellow spice in many Asian recipes. The 3-foot tall herbaceous plant produces 5-inch green leaves of culinary value and flowers. Outside of warm regions you grow turmeric as a houseplant or in a greenhouse. Turmeric is hardy in USDA hardiness zones 8 to 11.
Get a fresh turmeric rhizome from shops that market Asian foods and usually carry the fresh rhizome. Pick one that has a bud on one side. "All About Gingers" on the gingersrus website is also an online dealer that sells turmeric rhizomes for propagation.
Fill a seed tray with seed-starter mix.
Place the turmeric rhizome on the surface of the seed-starter mix with the bud facing up. Cover it with a thin layer of the planting mix.
Insert the tray into a clear plastic bag and seal it.
Place the bag on a propagation mat set at 20 degrees Celsius. It usually takes at least three weeks for a new plant to sprout. If you live in a hot climate, south Florida, for example, you don't need a propagation mat.
Remove the tray from the plastic bag and moisten the soil as soon as a turmeric shoot appears. Keep the tray in indirect sunlight and continuously irrigate the plant without making it wet.
Fill a 6-inch pot with potting mix when the turmeric plant is 2 inches tall. Transplant the seedling.
Water your new turmeric plant to maintain it moist. Keep the plant in light shade.
Feed your turmeric an all-purpose liquid fertiliser once a week in the growing season, spring and summer.
Spray the turmeric leaves with water if humidity is low. Turmeric is originally from a hot and humid tropical climate and becomes stressed when air moisture is low.
Transfer the plant to a well-lit area in fall. In addition, reduce its water, letting the soil dry up before irrigating it again so the plant goes dormant.
Transplant the turmeric plant outdoors in spring if your climate allows.
If you're growing turmeric for the kitchen, dig the rhizome out in the fall after the plant goes dormant. Use it fresh or dry. Standard grocery stores sell only the dried root.