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By Larry Hodgson
Ginger (Zingiber officinale) is well known as a tropical spice. We grow it for its spicy and refreshing taste and its delicious aroma.
Ginger is a “cultigen,” a plant that has never been discovered in the wild. It’s thought to have originated as a natural hybrid somewhere in the region formerly known as the East Indies, now Maritime Southeast Asia: perhaps Indonesia, Malaysia, the Philippines or New Guinea. And it has been grown in those areas as a spice and medicinal plant for at least 7,000 years, carried from island to island by boat. Now ginger is grown in tropical areas all over the world.
Like so many other plants in the Zingiberaceae family, ginger is an understory plant, creeping along the ground under jungle conditions. It produces an annual stem (actually, a pseudostem made up of the rolled bases of its leaves) of narrow lanceolate leaves arising from a thick, spreading, underground or partially underground rhizome.
Ginger rarely blooms outside of the hot tropics, so few people have ever seen its conelike inflorescences of purple and yellow flowers that look much like tiny orchids. They are sterile and produce no seeds.
You wouldn’t think you could grow such a tropical plant as ginger in a temperate climate, but in fact you can. It isn’t even that complicated … but you’ll likely need both indoor and outdoor space.
Starting Ginger at Home
You don’t grow ginger from seeds, as it produces none, but rather from rhizomes. You may see these called “seed” or “seed rhizomes” in some catalogs, much like tiny potato tubers are called seed potatoes. These rhizomes are harvested from plants grown the previous year.
To grow ginger, you need to find viable rhizomes. However, the rhizomes in your local supermarket have often been irradiated to prevent sprouting. They’ll therefore be useless to you. However, if you see any starting to produce small creamy or greenish growths (these are called eyes) on the rhizome, they’re good to go! Otherwise, look for organic ginger rhizomes, usually available at health food stores. They haven’t been treated and germinate readily.
Prefer a rhizome with several eyes: you’ll get a bigger harvest!
Start growing ginger indoors in late winter or early spring. Begin by soaking the rhizome in warm water overnight, as this can speed things along a bit. You could plant the entire rhizome as is, but for a greater harvest, cut the rhizome into sections at least ¾ to 1 in (2 to 3 cm) long. Each must have a viable eye.
Fill a 15 cm (6-in) pot about three-quarters full of moist potting soil (plain houseplant potting soil will work well). Then set a section of rhizome on the potting soil, eye or eyes pointing up. Add enough potting soil to cover it and water gently.
Place the rhizome in a warm location (72 to 77 °F/22 to 25 °C). If your growing area tends to be cool, consider setting the pot on a heating mat, at least until the air warms up.
It’s best to cover the container with a “mini-greenhouse” (a clear plastic dome or plastic bag) in order to maintain high humidity. Set it in good light, but with no more than indirect sunlight, at least, at this point, otherwise the planting may overheat.
Probably no watering will be needed for weeks, as not only is ginger is very “slow off the mark,” but a mini-greenhouse prevents most evaporation, therefore little water is lost and watering won’t be very necessary.
After about 3 to 8 weeks, green sprouts will start to emerge from the soil, a sign that the rhizome is well rooted. As the sprouts begin to elongate into green stems, remove the mini-greenhouse before the stems start to push against it. From then on, you’ll need to water more, keeping the soil slightly moist. You can also now move the plants to full sun for denser, shorter growth.
Tubular stems with long, narrow leaves will form and can reach 24 to 36 in (60 to 100 cm) in height before the end of summer. The plant likes high humidity, otherwise the margins of the leaves can dry out. It may be useful to use a humidifier at the beginning of the season, since the heating systems in our homes dry out the air.
You need to keep the plant warm throughout the growing season: certainly never less than 60 °F (16 °C).
You can fertilize regularly but lightly over the spring and summer with an organic fertilizer, following package directions, as ginger is a heavy feeder.
Indoors or Out?
You don’t have to put ginger outside for the summer. It will grow perfectly well indoors as long as you can supply strong light. Yes, it will “hang on” in shade indoors, but if you want rhizomes of any size to harvest, sun is important. You will need to repot it into a larger pot as it grows.
For outdoor growing, once both the soil and the air have thoroughly warmed up, start acclimatizing the plant to outdoor conditions. Place it in the shade for 2 or 3 days, then in partial shade for another 2 or 3. A location protected from direct sunlight would be suitable for its outdoor cultivation. You can plant your ginger directly in the garden even in a temperate climater, but it’s often more practical to grow it in a pot. If so, you’ll need a fairly large one, say a 12-inch (30 cm) pot, as small pots dry out too quickly.
Through the summer, just keep up the watering (never let it dry out) and fertilization.
Outdoor growing won’t be possible, though, in areas where summers are cool, such as some temperate maritime climates. If you can’t grow tomatoes or peppers outside of a greenhouse, the same will be true for ginger and you’ll need to grow it in your house or a greenhouse.
Of course, in tropical climates, you can plant ginger outdoors permanently where it will slowly spread and form a large clump over time.
In early fall, when the night temperatures drop, you can harvest ginger rhizomes. They’ll still be short and plump and yellowish with red scales, not long and beige like the original rhizome. That’s because they won’t be able to reach full maturity in a temperate climate. However, the taste will still be great and their texture is even superior: smoother and softer. And you won’t have to peel them, because their skin will still be thin. They’ll keep about 2 weeks in the refrigerator. Or freeze them and they’ll keep for 6 months or more.
You can keep a rhizome or two going over the winter if you want. However, many people find it more advantageous to start new plants each spring from larger store-bought rhizomes. You can also try forcing a few rhizomes into dormancy for two or three months in the winter by ceasing all watering, but this can be difficult, as home-harvested rhizomes will be immature and not ready for dormancy. It’s usually better to keep them growing right through the winter by maintaining watering, warmth, humidity and bright light. (Dormancy is not obligatory for ginger plants.)
What About Wild Ginger?
The plant called wild ginger (Asarum canadense) in eastern North America is not true ginger. Indeed, it isn’t even related to ginger, being from a different family, the Aristolochiaceae, and its heart-shaped leaves and low habit show no similarity to true ginger. However, its rhizome has a similar taste and is sometimes used to flavor foods and in herbal medicine. This deciduous groundcover is a forest dweller and very hardy, from USDA zones 2 to 8. Try naturalizing it in a shady woodland, but it certainly won’t grow indoors!
Ginger: so tasty, with quite a zing … and not really all that hard to grow!