How to Grow Shallots in Australia

Shallot (Allium cepa, Aggregatum group) is a clustering onion in the onion family, Amaryllidaceae, grown for small, mild bulbs that keep for months. Plant one bulb and it splits into a cluster, and a few saved bulbs replant next year's crop. In New South Wales, bunches of spring onions are often sold as shallots, and true shallots as eschalots; for the green kind, see spring onions. What trips most gardeners up is the soil: bulbs set too deep in heavy, over-fed ground tend to rot or keep poorly.

Three mistakes that matter

1. Burying the bulbs. A bulb pushed deep into heavy, wet soil sits cold and damp and can rot before it roots. Press each one in until only the tip shows, in free-draining soil or a raised bed.
2. Feeding for leaves, not bulbs. Fresh manure and late nitrogen give lush tops, thick necks and soft bulbs that rot in storage. Dig compost in weeks ahead, and stop nitrogen once the bulbs begin to swell.
3. Leaving the clusters in the ground. Once the tops yellow and fall over, the bulbs are ripe. Left in the ground, they begin a new growth cycle and the bulbs shrink, so lift them at that sign.

When to plant

Shallots make roots and leaves while days are short and cool, then swell their bulbs as days lengthen and warm. The season sets the window more than soil warmth. The old rule in southern gardens is to plant on the shortest day in June and lift on the longest in December. Plant once a year, since cured bulbs store well.

Late in a window, plant anyway rather than hold bulbs back, because stored bulbs sprout and soften as their season comes round. In warm zones, finish planting early so the bulbs ripen in dry weather.

Site, soil and setup

Shallots have a small root system, so loosen the top 15 to 20 cm well. Their thin leaves cast little shade, which leaves weeds free to compete for light, water and food. See soil pH and waterlogged soil for more on both.

Container growing

A pot at least 30 cm across and 30 cm deep, holding about 20 L, fits three bulbs. Fill it with a quality vegetable potting mix. Potting mix can carry Legionella bacteria, so wet it down, wear gloves and a P2 mask, and wash your hands afterwards. Red and golden shallots, at 35 to 40 cm tall, suit a pot best.

• Water whenever the top few centimetres of mix dry out; pots need water more often than beds.
• Feed fish and seaweed blend at 25 mL per 9 L fortnightly from shoots until the bulbs begin to swell. An all-purpose soluble (NPK 23-4-18 to 27-5-9) fortnightly at the label rate works too.
• Stand the pot in full sun, on feet so the base drains freely.

Planting Bulbs

Shallots start from bulbs pressed into the soil where they will grow, with no tray stage.

Golden and red shallots also come in golden and red packs of five. The assorted mix holds red, golden and banana shallots and potato onions, unlabelled, and all four grow the same way. Due to quarantine restrictions and our shipping policy, we cannot send shallot bulbs to Western Australia or Tasmania. For large single bulbs, see onions; for cloves, garlic and elephant garlic; for long white stems, leeks.

Preparation and vernalisation

Vernalisation is a spell of cold, roughly 5°C to 12°C for several weeks, that switches an onion-family plant from making leaves to making flowers. A shallot that flowers puts less into its bulbs, and those bulbs keep poorly. Store bulbs dry and airy at room temperature until planting, never in the fridge. Plant medium bulbs rather than the biggest, which bolt (run to flower) more readily. In cool zones, a late-winter planting spends fewer weeks in the cold.

Planting in the bed

• Split clusters into single bulbs just before planting.
• Press each bulb in, root plate down, until only the pointed tip shows.
• Space bulbs 15 to 20 cm apart in rows 20 to 30 cm apart.
• Firm the soil and water in with seaweed solution at 30 mL per 9 L.
• Keep the soil moist but not wet until shoots show.
• Birds sometimes pull new bulbs out. Push them back, and lay white, taut netting with mesh too small for a finger if it keeps happening.

Care by growth stage

Even moisture while the leaves grow, then a dry finish, decides how well the bulbs keep. Weeks count from planting; red shallots finish sooner, golden ones later, and cold weather stretches every stage.

Once shoots are up, mulch along the rows with straw to hold moisture and smother weeds. Pull any weeds that do come through by hand, because a hoe can nick the shallow bulbs.

Companion planting

Shallots are slim and low, so they tuck in beside other low crops that do not shade them.

Grows well with

• Carrots, whose fine foliage casts little shade on the shallot row.
• Lettuce, low and quick, picked before the shallots need the room.
• Beetroot and silverbeet, low leafy crops that leave the row in sun.

Keep apart

• Onions, garlic, leeks and chives, which share thrips, rust and white rot.
• Climbing peas and beans, which shade the low row.

Harvesting Bulbs

Lift shallots when most of the leaves have yellowed and fallen over, usually 14 to 26 weeks after planting.

• Lift one cluster first. If the bulbs are small, leave the rest two to three weeks and check again.
• Loosen the soil beside each clump with a garden fork, then lift the whole cluster.
• Handle gently, because bruised bulbs rot in storage.
• Leave the clusters whole while they cure.
• Set aside bulbs with thick necks or that tried to flower, and use them first.

Curing

Curing dries the skins and necks so the bulbs keep.

Store cured bulbs in mesh bags or open trays in a cool, dry, airy place. Check them often, and throw out any with sooty black mould under the skins or a strong-smelling watery rot.

Eat them raw in dressings, or roast or fry them. Pickle only by a tested method, such as CSIRO's preserving advice, because vegetables kept without enough acid can carry botulism. Keep scraps away from dogs and cats, because the onion family is harmful to them.

Common problems

Flower stems. A long cold spell, in the ground or in storage, pushes plants to flower (see Preparation and vernalisation). Snap stems off as they appear, as the flower draws energy from the bulb.

Small or single bulbs. Crowding, a late start or too little leaf before the days lengthen gives small bulbs, and very close spacing gives singles instead of clusters.

Bulbs going soft in storage. Bruises and short curing let rot in through the neck; see Neck rot under Pests and diseases.

Bulbs sprouting in storage. Shallots are perennial, and stored bulbs wake as their planting season returns. Plant the firm ones and cook the rest.

Pests and diseases

Shallots share the onion's pests and diseases, so use only sprays whose label covers shallots, at the label's rate and withholding period.

Onion thrips (Thrips tabaci). Insects about 1.5 mm long suck the leaf cells, leaving silvery-white flecks. Spray horticultural oil or soap solution several times, between 4 and 6 pm, and pull the weeds that shelter them. Read more

Aphids (Aphididae). Small sap-sucking insects cluster on the leaves and can spread viruses through onion crops. Hose them off or squash small colonies by hand. Read more

Downy mildew (Peronospora destructor). Pale yellow patches form on the leaves, then a greyish-purple growth in cool, wet weather. It has long been common in Perth market gardens in spring, and a copper fungicide may help. Read more

Onion rust (Puccinia allii). Bright orange or dark brown bumps form along the leaf veins, spread by wind and rain splash. It is not known in Western Australia, where rust on any shallot must be reported.

White rot (Sclerotium cepivorum). Leaves yellow and wilt, with white fluffy growth and tiny black specks at the bulb base. The specks survive in soil for up to 20 years, so keep that bed free of the onion family for at least ten.

Neck rot (Botrytis allii). Growing plants look healthy, then stored bulbs soften from the neck down under grey mould. Thorough curing is the main defence.

Prevention first

• Plant firm, healthy bulbs, because rust and downy mildew can travel on planting stock.
• Pull and bin plants with downy mildew as soon as it shows.
• Once white rot has appeared, keep onion-family scraps out of the compost and clean soil off tools and boots before working other beds.
• Space bulbs as advised, so air moves through the leaves and they dry quickly.

Tips

1. Keep your own planting stock: after curing, set aside firm, medium bulbs from the healthiest clusters, and never from a bed with white rot.
2. Snip a leaf or two from each plant early in the season for a mild green onion. Leave the rest to feed the bulbs.
3. Plant the assorted mix as one block. At harvest, tell the long banana shallots and the round, skin-wrapped potato onions apart by shape, and save each for next year.
4. Leave the dry tops on a few cured shallots and braid them into a string to hang in a cool, airy spot.