How to Grow Galangal in Australia

Galangal is a clumping perennial in the ginger family, Zingiberaceae, grown for peppery rhizomes (swollen underground stems) used in tom yum, curries and laksa. Two species usually carry the name: Thai red or greater galangal (Alpinia galanga), and the shorter lesser galangal (Alpinia officinarum), with smaller, sharper rhizomes. It thrives in warm, humid gardens and in large pots further south; most failures start in cold, wet soil.

Three mistakes that matter

1. Planting into cold, wet soil. A rhizome sitting in cold, soggy ground rots before it shoots. Wait for the soil warmth given in When to plant, and keep the soil just moist until shoots appear. Where spring is slow, pre-sprout pieces indoors.
2. Leaving it out through a frosty winter. Frost burns the leaves, and cold, wet soil rots the resting rhizomes. Where frost is regular, grow galangal in a pot and move it under cover before the first frost of autumn.
3. Waiting for one big harvest. Rhizomes turn tough and fibrous as they age, so a clump saved for one big dig gives woody pieces. Dig young, plump pieces from the side of the clump as you need them, as Harvesting Rhizomes describes.

When to plant

Plant once the soil stays at about 20°C or warmer, the warmth galangal needs to push shoots, which in most gardens means spring. In cool soil, sprouting is slow and uneven. One planting lasts for years, because the clump regrows each spring from the rhizomes left behind.

At the cool edge of a window, pre-sprout pieces in the warmth, as Planting Rhizomes describes, and plant out once nights stay mild. In the tropics, planting at the start of the wet season lets the rain do much of the watering.

Site, soil and setup

Choose a spot where the clump can stay for three or four years. Avoid beds where root-knot nematode (Meloidogyne spp.) has galled earlier crops, or where ginger or turmeric has rotted, as Companion planting explains.

Container growing

Use a pot of at least 75 L, about 50 cm across, filled with a good quality, coarse, free-draining potting mix.

Sand ginger (Kaempferia galanga) is also called galangal, but it is a different plant from both of these.

• Water: keep the mix evenly moist in the warm months, water less in winter, and never leave the pot standing in water.
• Feed: fish and seaweed blend at 25 mL per 9 L, fortnightly from spring to autumn. Or mix a controlled release all-purpose granular (NPK around 14-5-10) into the potting mix at planting, at the label rate.
• Position: as for a bed, see Site, soil and setup.
• Dividing: every year or two, as the rhizomes fill the pot, tip the clump out. Cut down through the root ball between sets of shoots with a clean knife, and repot the pieces in fresh mix.

Planting Rhizomes

Start galangal from a firm rhizome piece with at least two buds, planted straight into warm soil or pre-sprouted indoors first. Due to quarantine restrictions and our shipping policy, we cannot send galangal rhizomes to Western Australia or Tasmania.

Pre-sprouting

In Melbourne and cool and alpine gardens, start in September or October, since shoots take one to two months. Cut rhizomes at natural joints into pieces 5 to 8 cm long, each with two or more buds. Let the cuts dry for a few days. Sit the pieces on moist potting mix at about 28°C, on a seedling heat mat or in a warm room. Keep the mix below 30°C and never soggy, because heat and wet rot the pieces.

Planting out

• Plant 5 to 7 cm deep, buds facing up, so the soil just covers the rhizome.
• Space plants 30 to 45 cm apart.
• Keep the soil just moist, not wet, until shoots emerge, which can take several weeks.
• Harden off (accustom to outdoor sun and wind) pre-sprouted pieces for about a week, and handle the new roots and shoots gently.
• Set a crown (a piece with stems already attached) at the depth it grew, with its stems above the soil.
• Water sprouted pieces and crowns in with seaweed solution at half strength, 15 mL per 9 L.

Buy or keep only firm rhizomes, and discard any piece with soft, mouldy or discoloured patches.

Care by growth stage

Warmth, steady moisture and feeding in the warm months decide how many rhizomes a clump makes. Weeks count from a spring planting. Cold, not shorter days, slows galangal, so in the tropics it keeps growing and the last row applies only where nights turn cool.

Spread 5 cm of compost as mulch in spring to keep the shallow roots cool and moist. Each flowering stem dies down after it flowers, so cut it off at ground level.

Companion planting

Galangal fits a warm herb bed or the dappled understorey of taller plants, and should not follow related crops in the same soil.

Grows well with

• Lemongrass, which shares its liking for warmth, moisture and a harvest-as-you-go herb bed.
• Makrut (kaffir) lime and other taller fruit trees, which give the dappled light galangal grows well in as an understorey plant.

Keep apart

• Tomato, capsicum and eggplant beds with root-knot nematode, since all three host it, as galangal does.
• Ginger and turmeric grown in the same soil within three to five years, since rhizome rots carry over.
• Small herbs such as thyme and chives, which a spreading clump soon crowds out.

Harvesting Rhizomes

Young, plump rhizomes with pale or pink skin can be dug from the side of the clump from about four months after planting. A whole clump is usually ready 9 to 10 months after planting, once the lower leaves yellow or the stems dry and fall over.

• Push a fork in at the edge of the clump and break off the rhizomes you need.
• Leave the centre of the clump and its young shoots in place to keep growing.
• For a full harvest, lift the clump, shake off the soil and cut the stems 1 to 2 cm above the rhizome.

Store unpeeled rhizomes in an airtight container in the fridge and use them within a week or so. For longer storage, peel, slice and freeze them.

Slice, pound or grate the rhizome into curries, soups and spice pastes. The young shoots and peeled young stems of Thai red galangal can also be cooked as a vegetable.

Common problems

Rhizomes rot after planting. Cold, soggy soil lets rot in before shoots form, as Three mistakes that matter explains; for rot in warm, wet weather, see Pests and diseases. Read more

No shoots after several weeks. Cool soil slows and staggers sprouting, so check that a piece is still firm, then wait for warmer weather.

Curled leaves with brown tips. Dry soil curls the leaves and then burns their tips and edges, and harsh afternoon sun adds to it; water evenly and give afternoon shade.

Leaves yellow in autumn. Where nights turn cool, the clump slows towards its winter rest, which is normal and shows a mature clump is ready to lift. Yellowing with collapsing stems in warm, wet soil is rhizome rot instead.

Lush leaves, few rhizomes. Deep shade grows healthy tops over small rhizomes, so move the plant to the light in Site, soil and setup.

Small, crowded rhizomes. An old clump crowds itself, so lift, divide and replant fresh pieces every 3 to 4 years.

Pests and diseases

Galangal is seldom troubled by insects, and most losses start in the soil.

Root-knot nematode (Meloidogyne spp.). These microscopic soil worms include guava root-knot nematode (Meloidogyne enterolobii), found around Darwin and in Queensland, which lists galangal among its hosts. Infected plants look yellow, stunted and wilted, and their roots carry lumpy galls. Plant clean rhizomes, and dig in compost, which feeds the nematodes' natural enemies. Have suspect galls identified by your state or territory agriculture department before moving or sharing rhizomes. Read more

Rhizome rot (Pythium spp.). This soil water mould is a serious wet-weather disease of ginger in Queensland, and it rots rhizomes in warm soil as well as cold. Leaves yellow, stems collapse and pull away easily, and the rhizome goes soft. Lift and bin affected plants rather than composting them, and keep ginger-family crops out of that bed, as Companion planting describes.

Two-spotted mite (Tetranychus urticae). These tiny mites, under 0.5 mm long, feed under the leaves and leave a yellow, stippled mottle. Numbers climb fast in hot, dry weather and under cover. Keep plants well watered, and avoid broad sprays that kill the predatory mites and ladybirds that usually control them. Read more

Aphids (family Aphididae). These small sap-sucking insects can gather on soft new growth, especially on plants grown under cover. Squash small colonies or hose them off, and leave ladybirds and hoverflies to finish the job. Read more

Prevention first

• Start with firm, clean rhizomes, as Planting Rhizomes describes.
• Clean boots and tools after working in infested soil, since nematodes travel in soil and plant material.
• Water the soil, not the leaves, in the morning.
• Rotate beds as Companion planting describes, and add compost before each planting.

Tips

1. Drop the flowered stems you cut off back onto the bed as mulch, where they break down and feed the soil.
2. In Melbourne and other southern cities, a sheltered, north-facing courtyard or balcony is often the warmest spot for a pot.
3. Keep a few plump pieces with buds from each harvest as planting stock. Store them unwashed, with the soil still on, somewhere dry at about 13 to 16°C.