Ginger: how to grow, maintain, and harvest

Botany

Botanical illustration published in 1814.

The Zingiber belongs to the Zingiberaceae family, which includes many condiment plants that are the source of common spices such as turmeric, cardamom, and galangal. Likely originating from the humid tropical or subtropical regions of Asia, it no longer exists in the wild. Most herbaceous plants in the Zingiberaceae family share a common trait of having an underground rhizome that forms tubers, used as condiments since antiquity. This is true for ginger (Zingiber), whose fleshy, swollen tuberous rhizomes have a spicy and slightly lemony flavour.

There are several species in the Zingiber genus, with the aromatic ginger (Zingiber officinalis) being the most well-known. It is primarily cultivated in pots. In our regions, with a more oceanic than tropical climate, it is easier to cultivate Japanese ginger (Zingiber mioga), which is hardy down to -15°C. Widely consumed in Japan, it produces a yellow root with a milder flavour than that of aromatic ginger. The flower buds of this species bloom close to the ground at the end of summer and are edible.

Less common, Zingiber zerumbet is covered in inflorescences that produce a liquid used as shampoo, while Zingiber rubens, or red ginger, produces red flowers resembling those of orchids, close to the ground, like its cousin Zingiber mioga.

As for the flower of Zingiber spectabile, or honeycomb ginger, it is magnificent. The inflorescences resemble beehives and change from a coppery gold to a dark red as they mature.

The inflorescences of Zingiber spectabile evolve from coppery gold to dark red.

Other species related to ginger include Alpinia galanga, which is impressive for its tall stature and very ornamental flowers. Alpinia zerumbet ‘Variegata’, or shell ginger, features variegated foliage of green, yellow, and cream. As for Hedychiums, or ornamental gingers, they are covered in stunning yellow or orange flower spikes at the end of summer.

Alpinia galanga, Alpinia zerumbet ‘Variegata’, Hedychium

At first glance, one might almost confuse Zingiber officinalis with a corn plant. It indeed forms long stems that can reach 2 metres in its natural habitat, but rather 1 metre here, from which oblong and lanceolate leaves emerge. These bright green leaves, which grow in tufts, are sheathing and measure between 10 and 15 cm long. They give the plant a particularly lush appearance. Unfortunately, in our climates, flowers are not always present.

In autumn, the aerial parts of the Zingiber turn yellow and dry out, and the plant enters vegetative dormancy. This is the right time to harvest the rhizomes.

Between July and September, original inflorescences bloom on these stems. White to yellow, sometimes speckled with red on the lips, the flowers of aromatic ginger bloom at the heart of dense, leathery green and yellow bracts. They measure 10 to 15 cm and grow in irregular spikes.

The inflorescences of Zingiber officinalis

After flowering, the flowers give way to axillary spikes that contain black seeds enclosed in three-valved capsules. In contrast, those of Zingiber mioga are pale yellow and appear at the base of the stem, close to the ground.

However, ginger is primarily cultivated for its tuberous rhizomes, most of which are edible and widely used in Asian and Indian cuisines. The Japanese also enjoy the flower buds of Zingiber mioga, just emerging from the ground. The rhizomes of Zingiber are juicy and fleshy. They possess numerous medicinal and aromatic virtues. Whether consumed fresh, dried, ground into powder, or candied, ginger is known for its toning properties (and not aphrodisiac!), digestive, analgesic, expectorant, and anti-haemorrhagic…

Zingiber officinale is a tropical plant that is quite difficult to cultivate in open ground due to its needs for warmth and humidity. In contrast, Zingiber mioga is hardier and adapts well in French gardens. It will just require a good layer of mulch to keep the rhizome warm during the cold season.

The best species

Zingiber officinale

Ginger is only grown in open ground in regions that enjoy long periods of heat

• Height at maturity 1 m

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Zingiber mioga

Hardier, Japanese ginger is grown in open ground under protective mulching

• Flowering time August to October
• Height at maturity 50 cm

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Planting

Where to Plant?

As a reminder, ginger is a subtropical plant, so it requires warmth, moderate light, and humidity—conditions that can be challenging to find in our regions. However, it can be planted in the garden, in neutral to moderately acidic, light, humus-bearing, rich, and well-drained soil. It will need to be kept at a temperature of at least 25 °C for several months to develop properly. Additionally, watering should be regular but never excessive. During its winter dormancy, the soil should be relatively dry.

Regarding the location, it should resemble its natural habitat. A partially shaded position is ideal, and it should definitely not be placed in full sun during the hottest hours of the day.

Zingiber mioga is considerably less demanding. Highly ornamental, it can be grown in the garden due to its hardiness down to -15°C, in soil that remains cool but well-drained.

For both varieties, winter mulching is essential for outdoor cultivation. Additionally, protection from rain is recommended.

Both varieties are easier to grow in pots. The pot should be placed in a location that consistently maintains a temperature between 20 and 25 °C and in partial shade outdoors during summer. Remember to bring it indoors in September.

When to Plant?

Ideally, planting occurs in spring, in May for outdoor planting, and between March and June for pots.

However, if you wish to grow your ginger rhizome in a pot, planting can also be done in autumn.

How to Plant?

Before planting your rhizome, it is recommended to soak it in water to encourage sprouting. The rhizome should only be submerged halfway. Once several roots and shoots have appeared, you can plant it.

In the Garden

Plant your Zingiber rhizome in loosened garden soil enriched with compost or good-quality potting mix. The soil should be warm enough to welcome the young plant. Lightly bury the rhizome, leaving part of it exposed to facilitate the development of stems and leaves.

When planting, the ginger rhizome should be slightly exposed

Do not compact too much but water generously.

In a Pot:

• Choose a pot with a diameter of at least 30 cm and relatively deep.
• Place a layer of gravel or clay balls at the bottom of the pot to aid drainage.
• Fill the pot with a substrate made up of 1/3 garden soil, 1/3 compost or potting mix, and 1/3 sand.
• Insert the rhizome 2 to 3 cm deep, leaving part of it above the substrate surface.
• Lightly compact.
• Water generously.
• Place your pot in a location that maintains a temperature of at least 20 to 25 °C, and outdoors in summer.

Entretien

Two essential actions are required to ensure the development and survival of ginger: regular watering and mulching if your rootstock is in the ground.

The Zingiber needs a humid atmosphere, so the soil must remain cool without ever becoming waterlogged. Watering should be regular but not excessive, especially when the leaves reach 20 cm. Generally, in early autumn, the leaves begin to yellow, and watering should be stopped as the harvest of the rootstock is near.

In the ground, the rootstock must be protected in winter with a good layer of mulch at least 20 cm thick. Similarly, it should be shielded from rain to ensure the soil never becomes waterlogged. However, once the leaves have disappeared, lack of light is not an issue.

Pruning is unnecessary.

The Zingiber is not very susceptible to diseases and pests. However, in pots, due to the warm and humid atmosphere it needs to be kept in, scale insects may colonise its foliage. Recognisable by the cottony clusters and the sticky appearance of the leaves, scale insects can be eliminated with a cotton pad soaked in a mixture of soapy water and 90% alcohol, or by spraying a solution made of one teaspoon of liquid black soap, one teaspoon of 90% alcohol, and one teaspoon of rapeseed oil, diluted in one litre of water. Remember to ventilate the room where the Zingiber is located, and if it’s not too cold, take it outside on a rainy day.

Harvest

Between 8 to 9 months after planting, the rootstock can be harvested. It is essential to wait until all the leafy aerial parts have dried out. Around September or October, definitely before the frosts, you can lift the rootstocks with a fork if the ginger is planted in open ground, or by uprooting the plant if it is growing in a pot. Leave to dry for a few days in the garden.

The rootstock of ginger at harvest time

Harvesting can also be done 6 months after planting, but the flavour of the rootstock will be different, sweeter and less lemony.

You can store your rootstock for 3 to 4 weeks in the refrigerator.

Zingiber mioga is harvested differently. As the flower buds and young shoots are edible, collect them as soon as they appear. As for the rootstocks, they are harvested like those of its cousin, in autumn.

Multiplication

Ginger does not multiply by seeds. To obtain new young plants, rhizome propagation is used. During the harvest, keep parts of the rootstock that you (re)pot during winter. The rootstock enters vegetative dormancy. Keep your pot indoors in a place that is not too cold.

In spring, when the buds awaken, it is time to divide and plant new rootstocks.

Association

The growing conditions of Zingiber only allow it to be associated with tropical or subtropical plants that, in open ground, can only thrive in regions with a mild climate. Thus, the lush green foliage of ginger combined with the beautiful rhizomatous plant Curcuma alismatifolia, with its white, pink, or red flowers, also known as Siam Tulip, adds an undeniable exotic touch to a terrace or garden in the south. Ginger also pairs well with Alocasia macrorrhiza, or Elephant Ear, with its enormous, glossy green leaves. It also highlights the splendid flowers of Strelitzia reginae, or Bird of Paradise, and the colourful Abutilons.

Curcuma alismatofolia, Alocasia macrorrhiza, Strelitzia reginae, Abutilon

The various uses of ginger

Ginger has been incorporated into cooking for millennia for its flavour and medicinal properties. It can be consumed fresh or dried. Fresh, the rootstock is slightly tangy, sweet, juicy, and very tender. Once dried, it becomes stronger in taste and more fibrous. It can then be consumed grated or cooked in dishes.

Ginger is also used as a spice, included in blends such as garam masala, curry, or ras-el-hanout. It flavours desserts like gingerbread, and it is also enjoyed candied.

Ginger is part of the composition of gingerbread

Ginger is also included in drinks with a pronounced bitterness, such as ginger ale or ginger beer, which are widely used in cocktails. It is consumed in the form of ginger juice in Africa, and it can also be enjoyed in herbal teas or regular teas.