Growing Turmeric

Freshly dug turmeric roots.
Photo Pam Dawling

Our Crop Goals – Does Turmeric Fit?

I have never grown turmeric before, so this article is really my research and plan-making for next spring!

We have grown ginger in our hoophouse, and I’ve written about that in my book The Year-Round Hoophouse. In our zone 7a climate, ginger has to be started with heat in mid-March, and transplanted into our hoophouse in May, when the soil is 55°F (13°C) and rising. It then occupies the space for five months until October, when we harvest it before it gets too cold (it has no frost tolerance). Ultimately we decided to stop growing ginger. It is delicious, and if we were selling our crops, we might have made good money. But we are not selling; we grow food for direct use in our intentional community (Twin Oaks). Our goal is a wide range of healthy organic crops year-round to comprise as much of pour diet as possible. We need crops that provide a lot of nutrients over the time. Hoophouse crops are occupying valuable land, and fast-growing crops are more valuable than slow-growing ones. Cindy Conner’s “Bed Crop Months” is a concept more useful to us than $/sq ft. Crops that fill bellies and provide vitamins and fiber are more valuable than ones that provide only a little food. So, why turmeric?

A hoophouse with turmeric and carrots.
Photo Pam Dawling

About Turmeric

I was given two “hands” of turmeric roots by a farmer who was my guest. Turmeric has medicinal value, and (for me) novelty value, so I asked my hoophouse crew colleagues if I could grow a couple of plants next year. We have a tradition of accommodating small special projects of the crew. This winter we are growing some carrots in the hoophouse for the first time. I know lots of other growers produce carrots in hoophouses. We can grow perfectly good carrots outdoors in the fall, to store and feed us all winter. What do we gain by growing a few in the hoophouse? We’re about to find out.

Turmeric, if grown to maturity, will need from late April to October in our hoophouse, longer than ginger does. Both crops finish in time to plant those vital winter greens in late October.

Turmeric roots look like ginger but are more orange. Turmeric is easier to grow than ginger, but the market is smaller. Turmeric needs less feeding than ginger and as the rhizomes grow out and slightly downwards, it only needs slight hilling if the roots appear above the soil as it grows. Turmeric plants go dormant after 8–10 months of growth, at which point the roots are fully mature and can be saved to regrow next season.

A healthy hoophouse bed of turmeric.
Photo Pam Dawling

Using Fresh Turmeric

Turmeric doesn’t have to be dried and powdered before using—the flavor of the fresh root, whether grated or sliced, is earthy and slightly zingy. You can eat it raw like a carrot. You can grate it and make tea.

If you want to dry it, slice it thinly with a mandolin or a powered kitchen slicing machine. Having the pieces all of the same thickness will make for more even drying. Dry pieces may be ground with a coffee grinder. The distinctive yellow spice powder is used to flavor many Asian-inspired dishes. Turmeric contains curcumins which have valuable medicinal properties (reducing inflammation). The powder may be put in capsules to be taken medicinally.

Buying Turmeric Roots

Hawaiian Clean Seed, Puna Organics and Biker Dude sell turmeric roots shipped from Hawaii. Fool’s Paradise Farm, formerly Qualla Berry Farm, in North Carolina, sells both ginger and turmeric plants and sometimes galangal, another tropical root. They are now harvesting four varieties of fresh turmeric, available from now into December: Hawaiian Red, Indira Yellow, BKK, and Black.

If necessary, you can try growing turmeric from fresh grocery store roots, although they may have been treated with a sprouting inhibitor. When you buy turmeric rhizomes (if you are face-to-face with them) choose sturdy firm roots with many knobby leaf buds. If the knobs are slightly green, that’s a sign that they’re ready to sprout.

A quonset style hoophouse filled with turmeric in North Carolina
Photo Pam Dawling

How to Grow Turmeric

Late winter and early spring is the best time to plant turmeric. Snap the rhizomes into 2″ (5 cm) pieces, and keep them at room temperature for a few days to cure. Seed pieces weigh 1–2 oz (30–60 gm) each. Before planting, soak the root pieces in lukewarm water for a few hours. Cover the rhizomes with 2″–3″ (5–7.5 cm) of potting soil and water lightly. Set the crates of planted roots on a seedling heat mat in a plastic tent or in a germination chamber to sprout. Water the crates when the soil dries out, but do not over-water. It takes 2–4 weeks for the roots to sprout. When this happens, take them off the heat mat.

Grow your turmeric plants in your greenhouse until the danger of frost has passed, then plant them out into the hoophouse. The plant spacing is 6″ (15 cm) between seed pieces. Before planting, add some compost to the soil to improve the fertility. Afternoon shade is helpful. Feed the turmeric plants every few weeks during the growing season. Water daily in summer, with about 1″ (2.5 cm) of water each week. The plant will grow to 2’–3′ (60–90 cm). Turmeric plants may produce flower stems in late summer.

Turmeric growing outdoors in North Carolina. Hoophouse growing is recommended.
Photo Pam Dawling

Harvesting Your Turmeric

Because the plants are frost-tender, plan to harvest before your first expected frost. The plants will probably have begun to die back. Wear gloves when harvesting as the roots can stain your hands bright yellow! Dig up the plants, brush off excess soil and cut off the leaves just above the roots. Snap the roots apart as needed.

Once you grow your first crop you can build up seed stock of your own. Save pieces for replanting but don’t replant them right away. Store these roots unwashed in a plastic bag or box in a refrigerator until late winter. Turmeric is hardier than ginger, although frost-tender, and one grower in North Carolina reported overwintering plants outside in milder years, although the recommendation is to bring them in for the winter.