How to Grow Maca in Australia

Maca (Lepidium meyenii) is a small root crop of the cabbage family, Brassicaceae, grown for its turnip-like root and its peppery young leaves. It comes from the high Andes of Peru, and the seed usually comes up readily. The real test is climate: the root forms in cool weather, so most failures come from sowing into the wrong season.

Three mistakes that matter

1. Sowing into the heat. Maca grows best in cool days and poorly through hot summers. A crop left to swell in summer often gives leaf and little root. Time the sowing so the plants spend their six to nine months in the cool, as in When to plant.
2. Letting weeds win. The plant is a flat rosette that hugs the soil, and it competes poorly with anything taller. Weed by hand from the first week and thin early, as in Thinning, so each rosette has sun and room.
3. Keeping the soil sodden. Roots left in waterlogged soil rot or lose their quality and keeping life. Grow maca in free-draining soil or a raised bed, and water evenly rather than heavily.

When to plant

Sow when the soil or seed-raising mix sits at 15°C to 25°C. Maca does not need short days or a cold spell to form its root or to flower, so temperature alone sets the calendar. Choose a sowing date that lets the plant grow through the cool months and reach harvest before summer heat. In most of Australia that means an autumn sowing.

At the cold edge of a window, start seed indoors on a seedling heat mat and plant out later. At the warm edge, sow early rather than late, because roots still swelling when the heat arrives tend to stay small.

Site, soil and setup

Dig the bed well ahead of sowing, so the compost or manure below has time to settle.

Rotation matters because clubroot can infect any cabbage-family plant, and maca may draw the pests set out in Pests and diseases. Hold back on rich nitrogen feeds, which grow leaves at the expense of the root.

Container growing

Maca rarely grows wider than about 15 cm, so it suits a pot on a sunny, cool balcony. A 20 cm pot of about 5 L holds one or two plants. A 30 cm pot of about 13.5 L holds three or four. Choose a pot at least 19 cm deep, because the root and its tail run 10 to 14 cm long. The seed sold here is a single, unnamed line, so any plant from it suits a pot.

Fill the pot with premium potting mix. Potting mix can carry Legionella bacteria, so wet it first, wear gloves and a face mask to handle it, and wash your hands afterwards.

• Water: keep the mix evenly moist and never let the pot sit in a saucer of water.
• Feed: fish and seaweed blend at 25 mL per 9 L, fortnightly from the first true leaves.
• Position: full sun through the cool months; move the pot out of hot afternoon sun in warm spells.

Germinating the seed

Maca seed has no dormancy (no built-in delay that needs soaking, scratching or chilling to break). It needs only moisture and warmth. At about 25°C it can come up in five to seven days. At 15°C to 20°C expect one to two weeks; in cold soil it can take a month or more.

In laboratory trials with Peruvian seed, a daily cycle of 4°C to 20°C gave over 70 per cent germination. Seeds took 22 days or less on average. A cycle between 4°C and 15°C gave less than 60 per cent, taking more than 25 days. No source gives a home-garden rate, so sow two or three seeds for each plant you want and thin to the strongest.

When nothing comes up

• Too cold: below about 15°C germination slows and falls away; bring the tray indoors or onto a heat mat.
• Surface dried out: a 2 mm seed near the surface dries fast, and dry mix slows germination; keep it damp with a fine spray.
• Sown too deep: more than 5 mm of cover buries this tiny seed; sow again at the surface.
• Old or warm-stored seed: seed kept at about 16°C holds above 80 per cent for two years, then falls to about half. Sow old seed thickly.
• Rotted in cold, wet mix: seed can rot before it emerges (pre-emergence damping off); use fresh seed-raising mix and keep it damp, not soggy.
• Given up too soon: in cool conditions wait six weeks before resowing.

Sowing Seeds

Start maca in trays under cover in cool weather, or sow direct at the soil warmth in When to plant, following Germinating the seed.

Starting under cover

• Sow two or three seeds per cell of seed-raising mix, pressed onto the surface and barely covered.
• Thin to the strongest seedling in each cell once the first true leaves open.
• Plant out at four to six weeks old.
• Harden off first (move the seedlings outdoors for a few hours more each day over about a week), as in hardening off.

Sowing direct

Mix the seed with a little dry sand so it spreads evenly, much as Andean growers mix seed with soil before broadcasting it. Sow in shallow drills 30 to 40 cm apart, cover lightly, and keep the surface damp until the seedlings show.

Transplanting

Set each seedling at the depth it grew in the cell, 10 to 15 cm apart in rows 30 to 40 cm apart. Water in with seaweed solution at half strength, 15 mL per 9 L.

Care by growth stage

Cool weather, steady water and clean, weed-free soil decide the size of the root.

If growth stalls in poor soil, a light application of all-purpose controlled release granular (NPK around 14-5-10) scratched into the soil can help. In the Andes a maca crop leaves the soil so spent that fields rest for years.

Thinning

Andean growers thin about two months after sowing for larger, more even roots; in a garden, start as soon as seedlings can be handled.

• Thin direct sowings in two passes, first to about 5 cm, then to 10 to 15 cm.
• In dry districts without regular water, allow up to 25 cm between plants.
• Pull the weaker seedling and press the soil back around the one that stays.
• Weed by hand at each pass rather than hoeing close to the roots.
• Eat the thinnings: the young leaves taste peppery, like garden cress.

Companion planting

Low and slow, maca does best with neighbours that neither shade it nor share its pests.

Grows well with

• Garlic and onions, which share the cool season but not the cabbage family's caterpillars and aphids.
• Lettuce, a quick, low crop that fits between rows and is gone before the rosettes spread.

Keep apart

• Cabbage, broccoli, kale and turnips, which carry the same caterpillars and aphids.
• Pumpkins and corn, which sprawl over or shade the flat rosettes.

Harvesting Roots

Lift maca when the roots are firm and 3 to 5 cm across, usually six to nine months after sowing. The first flower buds in the centre of the rosette are the signal.

• Brush soil from the top of a root to check its width before lifting the row.
• Loosen the soil beside the plant with a fork and lift it by hand, so the blade does not cut the root.
• Harvest while the leaves are still green and growing.
• Where the ground does not freeze, leave roots in the soil and dig them as needed.
• Keep a few of the best plants in the ground to flower if you want your own seed.

Fresh roots keep for up to two months in the fridge at about 2°C to 3°C with high humidity, for example in a lidded container. To dry roots the Andean way, spread whole plants in the sun for 10 to 15 days. Cover them at night against rain and frost. Dried roots turn stone-hard and keep for up to two years in a dry, airy place.

In the kitchen, roast, bake or boil fresh roots as you would turnip; they taste earthy, with an aroma like butterscotch. Young leaves go raw into salads or are cooked like other greens.

Traditional use and history

Maca was probably domesticated around San Blas, now Ondores, in the Junín highlands of Peru, some 1,300 to 2,000 years ago. Its heartland is the Junín and Pasco highlands above 3,500 m, where frost is frequent and little else will crop. In the mid 1500s the Spanish chronicler Cieza de León described highland people living on certain roots in Bombón province. Those roots were maca. A century later, Father Cobo named the plant and wrote that it grew where no other food crop could.

Colonial writers recorded that many highland people had no other food but maca, and that the roots were paid as tax to Spanish administrators. Roots were buried as offerings with potatoes on Mount Raco, honoured as the god of stewed food. Roots were cooked in pachamanca earth ovens, and dried roots could be stored for years.

In Andean folk belief, maca was linked with fertility in people and in livestock. Early Spanish settlers grazed their horses on maca fields, and the crop was fed to pigs, chickens and horses for the same reason. Later market sellers in Peru added many more claims, which researchers of the 1990s noted had not been shown by science.

By the early 1990s fewer than 50 hectares were grown, and the crop was described as near extinction. Demand then rose sharply, and plantations have since been established well outside the Andes, in Yunnan in China. It is known only as a cultivated plant, and none of the wild Lepidium species studied is its close relative. Its garden cousins include garden cress.

Safety

Maca is sold as seed for growing, and nothing here is advice to eat or take any part of the plant. Anyone thinking of using a plant should first seek advice from a qualified health practitioner.

Common problems

Big leaves, small roots. Heat, shade, crowding or rich nitrogen feeding, as in Three mistakes and Site, soil and setup. Sow by the zone table and thin early.

Flower stems before harvest. The root is full size when buds show; lift at once, as in Harvesting Roots.

Roots rotting or keeping badly. Sodden soil, as in Three mistakes; fix the drainage as in Site, soil and setup. Read more

Roots in mixed colours. Maca seed is gathered in bulk from many plants, so one sowing can give cream, yellow, purple and darker roots. This is normal, and every colour is maca.

Gaps in the row. Seed sown too deep, a surface left to dry, or cold soil; see When nothing comes up.

Pests and diseases

Few pests have been recorded on maca anywhere; in Australian gardens, watch for the pests of its cabbage-family relatives.

Cabbage white butterfly (Pieris rapae) and diamondback moth (Plutella xylostella). Green caterpillars of both chew the leaves; young diamondback caterpillars graze windows that tear into holes. Cover young plants with fine insect mesh and squash eggs and caterpillars under the leaves. Read more

Cabbage aphid (Brevicoryne brassicae). Grey-green aphids in colonies under the leaves, flying in from wild radish, wild turnip and other cabbage-family weeds. Hose small colonies off or spray insecticidal soap, following its label. Read more

Common garden snail (Cornu aspersum) and slugs. They favour soft seedlings and cabbage-family crops, so young maca seedlings are at risk. Hand-pick after dark and protect seedlings until the rosettes firm up. Read more

Damping off (Pythium species and Rhizoctonia solani). Soil fungi rot the stem at soil level and seedlings collapse, worst in wet mix and when growth is slow. Use fresh seed-raising mix and avoid overwatering. Read more

Redlegged earth mite (Halotydeus destructor). Velvety black mites about 1 mm long with orange-red legs that silver the leaves of many crops, including canola, from autumn to spring. Heavy numbers can kill seedlings, so check autumn sowings in southern Australia for three to five weeks. Look on the leaves in the morning or on a cloudy day, and at the plant base when it is warm.

Prevention first

• Cover young plants with fine insect mesh or white, taut netting with holes too small for a finger, which also keeps birds off.
• Turn a few leaves each week to check for eggs, caterpillars and aphids.
• Pull wild radish, turnip weed and other cabbage-family weeds nearby.
• Water the soil in the morning, and raise seedlings in fresh seed-raising mix.

Tips

1. Save your own seed. Maca pollinates itself, often before the flower opens, so plants of different colours can grow side by side and still come true.
2. Gather seed as the pods start to yellow. Lift whole plants before the pods split, dry them, then rub the seed out by hand.
3. Store seed sealed, cool and dry, ideally in the fridge. Seed kept frozen and dry in a Peruvian genebank held close to 95 per cent germination over five years.