Growing Turmeric and Ginger in Zone 5

Growing Guides
Written By Kevin Wallace

Hey folks, Kevin here.

We do not grow turmeric or ginger here anymore. We tried them in pots. The work area ran a little too cold, and we never got the amount of root that would have made the pots worth the bench. Thea grows the houseplants, and she would rather keep those spots for her ornamentals than for these two. With the schedule we already have, we are not going to designate that time again. Both plants are tropical rhizomes, hardy outdoors in roughly zones 8 to 10, so a zone 5 winter was never going to carry them in the ground (1). On the May 23, 2014 update I still had turmeric under the seedling planters. That experiment is done.

What follows on growing is what other institutions recommend, not what we are doing on this property.

Where the skeptics are right

Most of the human trials are not testing the teaspoon in the soup pot.

Curcumin is only about 2 to 5 percent of turmeric powder. A teaspoon of powder is on the order of 2 to 3 grams of spice, so roughly 50 to 150 milligrams of curcumin. Knee-osteoarthritis trials use extracts, often hundreds of milligrams to about a gram of curcuminoids a day, for 4 to 16 weeks (2). The National Center for Complementary and Integrative Health still says we do not know enough to conclude that turmeric or curcumin is beneficial for any health purpose, even though the early osteoarthritis numbers look favorable (3).

Ginger has a cleaner traditional job — nausea — and a smaller, real effect on osteoarthritic pain. It is not a joint replacement, and it is not an anti-inflammatory drug.

Poor absorption is the other honest limit. In a 1998 study of healthy volunteers, 2 grams of curcumin alone left blood levels undetectable or very low. The same dose with 20 milligrams of piperine, from black pepper, raised measured exposure about 20-fold (4). That “2,000 percent” figure is why every golden-milk recipe adds pepper. It is also easy to misuse. Baseline was near zero, so the percentage is large and the absolute amount in the blood is still small. Michael Greger’s NutritionFacts piece on this study is a fair plain-language walk-through, with the same caveat attached (5).

What the compounds are doing

Turmeric (Curcuma longa) and ginger (Zingiber officinale) are cousins in the ginger family. The yellow pigment in turmeric is a set of curcuminoids, mainly curcumin. The bite in fresh ginger is mostly gingerols, especially 6-gingerol. Drying and heat shift some gingerol toward shogaols. That is chemistry, not a reason to prefer a capsule over the root in the pan.

In cell and animal work, curcumin is described as turning down NF-κB and COX-2, two switches in inflammatory signaling. Those are mechanism papers. They do not tell you what a pinch in lentil soup does to a person’s knee. The human evidence worth reading is narrower.

StudyWhat it testedWhat it foundWang et al., 2021, turmeric extracts for knee osteoarthritis16 randomized trials, 1,810 adults, up to 16 weeksExtracts reduced pain and improved function versus placebo. Effects looked similar to NSAIDs. Fewer adverse events than NSAIDs. Heterogeneity was high.Zeng et al., 2021, Curcuma longa and curcumin for osteoarthritis15 randomized trials, 1,621 peopleLower pain and stiffness scores than placebo. Similar to NSAIDs, with fewer adverse events. Authors suggested use beyond 12 weeks. Imaging and lab markers did not clearly change.Bartels et al., 2015, oral ginger for osteoarthritis5 placebo-controlled trials, 593 patientsModest pain reduction (standardized mean difference about −0.30) and a smaller disability reduction. Moderate-quality evidence. People on ginger were more likely to stop, mostly from stomach upset.

NCCIH’s read of the turmeric osteoarthritis meta-analyses matches that table: initial evidence is positive, higher-quality work is still needed, and bioavailability is an open variable (3). An older umbrella review of ginger-family extracts and curcumin reached a similar, cautious conclusion across metabolic and inflammatory outcomes, and a clearer one for ginger and nausea (6).

Ginger’s best-supported use is short-term nausea, including pregnancy nausea at food-scale doses, chemotherapy-related nausea, and postoperative nausea. That is the NCCIH summary, not a dosing chart for this article (7). If you are pregnant or on anti-nausea drugs, that is a conversation with your own clinician, not with a garden website.

What other institutions recommend, if you still want to try pots

We are not running these pots. University of Vermont Extension and the Cooperative Extension system both treat turmeric and ginger as container plants north of zone 8. They want warmth, at least the upper 60s, and they should not sit below 50°F. A hard frost outdoors is the end of the crop (1) (8). That temperature line is the part we already learned the hard way. The work area got a little too cold, and the roots never amounted to much.

StepWhat Extension recommends in zone 5WhyStockGrocery or nursery rhizomes with visible eyes. Organic if you can get it.Conventional produce is sometimes treated to stop sprouting.StartFebruary or early March, indoors, on a heat mat if the room is cool.Rhizomes need 8 to 10 months. A frost-free window here is not that long.PotAt least 12 inches wide and deep, drainage hole, loose mix. Rhizome flat, eyes up, about 2 inches of mix over it.They creep sideways. Wet, cold mix rots them.WaterSpare until sprouts. Then moist, never soggy.Three to eight weeks to sprout is normal. Turmeric is the slow one.OutsideAfter last frost, morning sun, afternoon shade. Bring in before nights near 50°F.Afternoon sun on a pot in July cooks the leaves. Cold nights stall the root.HarvestWhen leaves yellow, or before a hard freeze, whichever comes first. Save fat fingers with eyes for next February.A northern pot is not a tropical yield.

Cost and time, said plainly: a bag of rhizomes, a couple of pots, potting mix, and most of a year of attention for a harvest you could buy at the co-op for a few dollars. The house is the warm place these plants actually want. If that space is already spoken for, as ours is, the honest move is to buy the root. That is what we do now.

Honest caveats

  • Extracts and food are different. A trial that used 1,000 milligrams of curcuminoids is not evidence for a quarter teaspoon in rice.

  • Osteoarthritis results are symptom scores over weeks, not rebuilt cartilage. Biochemical markers and imaging did not clearly move (2).

  • Some imported turmeric powder has been adulterated with lead chromate to brighten the color and add weight. That showed up in Bangladesh supply chains and in recalled U.S. product. Buy from a supplier who tests for lead (9).

  • High-dose curcumin and piperine are not free of drug interactions. Piperine slows liver and gut metabolism of some drugs. Curcumin can add to bleeding risk with anticoagulants, and it is a poor idea if you have a bile-duct obstruction or gallstones. NCCIH flags these (3).

  • Ginger in the amounts used for nausea is usually well tolerated. The osteoarthritis trials saw more dropouts from stomach upset, and ginger can also add to bleeding risk at supplement doses (7) (10).

  • This is not a treatment page. Nothing here replaces care for arthritis, nausea in pregnancy, or inflammatory disease.

Where we land

On this place, turmeric and ginger are grocery items. We tried the pots. The work area was too cold, the house is Thea’s for ornamentals, and the time is already spoken for. The compounds are real. The doses in the better trials are extract doses. The dose in the pan is a flavor dose, and that is still worth cooking with.

  1. If you have a warm room and the time, Extension’s pot schedule above is the method. We do not. Buy the rhizome or a tested powder.

  2. Cook with the powder or the fresh root most days if you like it. Pair turmeric with a pinch of black pepper and some fat, the way curry already does. That is the practical reading of the 1998 absorption study (4).

  3. If knee pain is the reason you are looking at a bottle, read the osteoarthritis meta-analyses and talk with your clinician before you add an extract, especially if you take a blood thinner or a drug with a narrow margin (2) (3).

  4. Skip bargain turmeric powder with no lead testing. The color is not worth it (9).

  5. Size the expectation to the plant and to your winter. A cold work room will not fill the spice rack. We already ran that trial.

The closest video on the channel is the May 23, 2014 walk-through, back when turmeric was still under the planters: Mindful Living Sanctuary update 5-23-2014.

Disclosure: if you use our Amazon affiliate link when you buy anything, we may earn a small commission at no extra cost to you. That is not a product endorsement for any curcumin capsule.

Further Reading

If you only open three of these, open the NCCIH turmeric page, the Wang osteoarthritis review, and the Vermont Extension grow sheet. The first two will keep you from confusing a pinch of turmeric with a prescription. The third is for someone who still has a warm room and the months. We do not.

On Our Website

The carb piece is the nutrition chapter this one sits next to: whole plants first, extracts only with your eyes open. The growing pages are the beds we do keep after, not these two pots.

Kevin Wallace
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