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Potato Onion

Potato Onions (Allium cepa var. aggregatum) are the perfect blend of flavour, resilience, and practicality. A natural cross between an onion and a shallot, they combine the rich, mellow taste of both in one versatile crop. Each bulb multiplies underground, forming clusters of richly flavoured, easy-to-use onions that are milder than standard onions but more robust than shallots. They’re incredibly low-maintenance, less prone to bolting, and store beautifully for up to 6–8 months when cured. Best grown in full sun, they thrive in cool, temperate, arid, and semi-arid climates with mild to cold winters and steady spring conditions. Plant them once, and with just a few saved bulbs, you can enjoy reliable harvests year after year. Ideal for roasting, caramelising, or adding depth to everyday dishes, Potato Onions are a smart, sustainable choice for every productive garden.

SKU: TCPOTONI005 Category: Edible Produce Tags: Allium cepa var. aggregatum, Potato Onion

Description
Additional information

Description

Quarantine Note: Due to quarantine restrictions, potato onion bulbs cannot be sent to Western Australia or Tasmania.

Potato Onion
Potato Onion (Allium cepa var. aggregatum) is a reliable, easy-to-grow multiplying onion with a mellow, full-flavoured taste. Also known as Mother, Nesting, or Pregnant Onions, this variety is larger than shallots but smaller than standard onions, with a rich, mellow flavour that falls between a mild onion and a stronger shallot. Grown much like shallots, they are a fuss-free crop with fewer tendencies to flower, making them a more reliable option for storage. In ideal conditions, bulbs can be stored for 6–8 months or longer. With just a few saved bulbs, you can keep your crop going year after year, making Potato Onions a smart and sustainable addition to any productive garden.

How Potato Onions Grow
Potato Onions grow from individual whole bulbs that multiply underground, forming clusters of 10–12 new bulbs per plant. Each bulb should be firm and intact, with a healthy base where roots and shoots will develop. After planting, growth begins as the soil warms—roots emerge first, followed by green leafy shoots above ground. As the season progresses, the bulb divides below the surface to form a productive clump. Strong, upright foliage is a sign of healthy growth. Plants mature in summer when the tops yellow and flop. You can harvest slightly earlier for fresh use, though bulbs lifted too soon may be smaller and won’t store as well.

Planting Time and Climate
Best suited to cool, temperate, arid, and semi-arid climates with mild to cold winters and steady spring conditions. In warmer, dry-winter areas, plant in autumn to allow bulbs to establish before the heat. In cooler or wet-winter areas, plant from late winter to early spring to avoid soggy soil and support healthy growth.

Potato Onions are less prone to bolting than shallots, but following these times encourages strong early growth and reliable harvests. Choose a full sun position with airflow and well-drained soil—avoid shaded or damp spots.

Site and Soil Preparation
Plant in rich, well-drained soil with a pH around 6.5. Improve soil structure with compost, and use well-rotted manure sparingly to avoid excess nitrogen. If your soil is acidic, apply lime several months before planting. In poor soils, add blood and bone or a low-nitrogen fertiliser. Raised beds are ideal in heavy or damp conditions.

How to Plant
Plant bulbs base-down with the neck level with the soil surface. Potato Onions don’t need to be planted as deeply as other shallots, but should be firm and well anchored to prevent disturbance from wind or rain. Space bulbs 20–40 cm apart, with 30–60 cm between rows for clump formation.

Mulching is optional but beneficial, helping to suppress weeds and retain moisture. Apply after shoots emerge in cool or wet regions, or after planting in warmer, drier areas. Keep mulch clear of bulb necks.

Growing in Pots
Use wide tubs at least 30 cm deep to allow room for root development and clump formation. Plant bulbs 1–5 cm deep and 20–40 cm apart, with the tips just visible above the surface. Smaller tubs may restrict growth and limit bulb numbers. Use a well-draining, compost-enriched potting mix. In cooler or wet climates, bulbs can be started early in trays or small pots and transplanted when conditions improve.

Watering
Water lightly if the soil is dry after planting. Keep soil evenly moist during growth, watering when the surface dries. Avoid soggy soil. Reduce watering as bulbs form; stop once tops yellow and flop.

Fertilising
Use low-nitrogen fertiliser like blood and bone at planting. Feed lightly with nitrogen during active growth. Stop once bulbs begin swelling.

Mulching
Apply a light mulch once shoots appear and the soil warms. Use dry straw, sugarcane, compost, or grass clippings. In warm or dry areas, mulch can be applied after planting. Keep mulch away from bulb tips.

General Care
Weed regularly to reduce competition. Hand-weed to avoid root disturbance. Ensure good airflow. If bolting occurs, remove flower stalks promptly to encourage better bulb development. Bolting can’t be reversed and is usually triggered by cold or temperature stress. Bolted bulbs can still be eaten fresh but won’t store or regrow well.

Harvesting and Curing
Harvest when the tops yellow and flop. Lift gently and shake off soil. Cure in a dry, airy spot with indirect light for 2–3 weeks until skins are papery and necks dry. Keep foliage attached during curing to reduce rot. Once cured, trim tops and roots, then store in mesh bags or trays in a cool, dry, ventilated place with light to prevent sprouting. Use thick-necked or bolted bulbs fresh, as they don’t store well. Cured bulbs keep for 6–8 months.

You can snip some green tops for cooking, but leave at least half to support bulb growth. Save the largest bulbs for replanting next season.

Pests and Diseases
Potato Onions are generally hardy but can still face common onion pests and diseases, especially in poor conditions or reused soil.

Common issues include:
• Onion thrips – cause leaf streaks; treat with neem or insecticidal soap.
• Bulb mites – prevent by using healthy sets and crop rotation.
• Rodents/birds – protect with netting.
Diseases include:
• Downy mildew – leaf spots; improve airflow and remove infected plants.
• Neck rot – storage issue; prevent with proper curing.
• White rot – soil fungus; rotate crops to manage.
• Black mould – dark spots on bulbs; prevent with dry, well-ventilated storage.
Good drainage, airflow, weed control, and curing minimise problems.

Safety
Potato Onions are safe to eat cooked or raw. Supervise young children around planting areas and harvested bulbs. Like all onions, they can be toxic to pets, especially dogs and cats, if eaten in large amounts. Monitor pets and seek veterinary advice if illness occurs. Wear gloves if you have sensitive skin.

Supplied as dormant bulbs.

Additional information

Price Code	C – Orange Pack
Botanical Name	Allium cepa var. aggregatum
Quantity in Pack	5 Bulbs
Harvest Time	Harvest typically occurs between December and January. In warmer regions, bulbs may mature slightly earlier, so harvesting can take place during the warmer months. Monitor plants closely for signs of readiness before lifting.
Planting Time	Plant Potato Onions from April to July, in line with the traditional autumn planting period. In warmer regions, planting may commence earlier in autumn and continue through to July, as the extended mild conditions support strong establishment. In cooler regions, planting is still suitable during this period; however, care should be taken in areas with cold, wet winters. While Potato Onions favour moist soil during growth, they are susceptible to rot in waterlogged conditions. In regions with heavy or poorly draining soils, raised beds are recommended to improve drainage and allow earlier planting. Where winters are particularly wet, it may be best to delay planting until late winter to early spring, once conditions improve. This approach gives the bulbs the best chance of forming a healthy cluster and reduces the risk of losing some to rot or cold-related stress.
Planting Depth	Plant bulbs so the neck sits at soil level with the tip exposed. Potato Onions can be planted shallower than other shallots, but ensure they’re firm in the soil to stay anchored and undisturbed by weather.
Planting Width	Space each bulb 20–40 cm apart and 30-60 cm apart in between rows.
Soil	Potato Onions grow best in rich, organic, well-drained soil with a slightly acidic to neutral pH around 6.5. Testing your soil pH before planting is helpful, as these onions don’t perform well in strongly acidic conditions. To improve structure and fertility, add compost or well-rotted organic matter. Compost is stable, safe, and improves texture and drainage without greatly altering pH. Avoid fresh manure—it’s high in ammonia and salts, which can burn roots and young bulbs. If well-rotted manure is your only option, use it moderately and mix it well into the soil. Excessive manure, especially in acidic soils, can lead to nutrient imbalance, soft growth, and poor bulb development. Always retest the pH after adding manure, and apply lime if it drops below 6.5. In heavy or poorly drained soils, compost is particularly useful for improving texture and reducing rot risk. You can also blend in coarse materials like sand or grit. Raised beds or mounded rows help prevent waterlogging and bulb rot. If you’re not using compost or manure, apply a low-nitrogen fertiliser like blood and bone when preparing the soil to support strong root and bulb development. If organic matter is added, a light fertiliser application can still be beneficial—just avoid overfeeding, as too much nitrogen can lead to excessive leafy growth at the expense of bulb size and storage quality.
How to Plant	Choose a sunny, sheltered position that receives at least six hours of direct sunlight per day. Potato Onions grow best in full sun with good airflow, which encourages strong foliage and reduces the risk of fungal issues like downy mildew. Avoid shaded or overly damp spots, especially in high rainfall areas. Once the site is prepared, plant each bulb base-down with the neck level with the soil surface. Potato Onions don’t need to be planted as deeply as other shallots, but they should be firmly anchored to prevent movement from wind or rain. Space bulbs 20–40 cm apart, with 30–60 cm between rows to allow for clump formation and airflow. If the soil is dry at planting time, water in lightly to settle the soil. If there’s already enough moisture, additional watering isn’t necessary. Mulch is optional but beneficial—it helps suppress weeds and retain soil moisture. In cool or wet regions, apply mulch after shoots emerge. In warmer or drier areas, mulch can be applied after planting. Keep mulch clear of the bulb necks to prevent smothering. Potato Onions can also be grown in deep pots or tubs (at least 30 cm deep) using a quality, well-draining potting mix enriched with compost.
Watering	Water lightly after planting, especially if the soil is dry, to help settle the bulbs and encourage root establishment. During the active growth phase, keep the soil evenly moist but not waterlogged, watering when the surface feels dry to the touch. Potato onions are sensitive to soggy conditions, which can lead to bulb rot and fungal diseases, so avoid overwatering. As the season progresses and bulbs begin to form—typically in late spring to early summer—gradually reduce watering. This allows the bulbs to mature properly and improves their storage quality. About two weeks before harvest, withhold watering entirely to allow the bulbs to dry out and firm up before lifting. Allowing the soil to dry out at this stage helps prevent rot and prolongs bulb shelf life. The tops will be yellow and flop over, indicating the end of active growth and that the bulbs are ready for harvest. Healthy, vigorous leafy growth by late spring is a good indicator of a promising harvest, as it supports strong bulb development.
Fertilise	Apply a low-nitrogen fertiliser when preparing the soil to promote strong root development and establish healthy plants without encouraging excessive leafy growth that can delay bulb formation. When growth appears, apply nitrogen-rich fertilisers to support vigorous leaf development, which is essential for producing large, healthy bulbs. Be careful not to over-fertilise, as too much nitrogen during bulb swelling can result in soft, lush growth that reduces bulb firmness and shortens storage life. Stop fertilising once the bulbs begin to swell, usually in late spring to early summer, to encourage the plant to focus energy on bulb maturation. For best results, follow manufacturer instructions and adjust feeding based on soil fertility and plant health.
Harvest	Harvest Potato Onions when the tops yellow and flop—this signals that bulb growth has finished, and skin formation has begun. For best results, harvest on a dry day to minimise the risk of mould or rot during curing. If conditions are damp, gently lift the bulbs and lay them out under cover with good airflow. Shake off excess soil. Bulbs picked too early may be used fresh but won’t store well. Curing helps the bulbs dry fully and form a protective papery skin. Lay them in a dry, shaded, well-ventilated space for 2–3 weeks. Avoid direct sun, and keep the foliage attached to allow moisture to escape and prevent rot. Once cured, trim roots and tops, then store bulbs loosely in mesh bags or shallow trays in a cool, dry, ventilated space with indirect light. Hanging mesh bags improves airflow and reduces mould risk. Avoid plastic or sealed containers. Discard any soft or damaged bulbs, as they are more likely to rot or affect healthy ones. Properly cured Potato Onions can store for 6–8 months, or longer in ideal conditions. While the bulbs are maturing, some green tops can be harvested and used like spring onions but always leave at least half of each leaf to support bulb development. Potato Onions are known for their mellow, full-flavoured taste and are excellent for roasting, caramelising, and adding to soups, stews, and casseroles. They store better and are more resilient than standard onions, making them a dependable crop for home gardeners. Bolting is uncommon, but if flowering occurs, remove the stalk promptly. Bolted bulbs can be eaten fresh but should not be stored or replanted. To continue growing Potato Onions each year, save your largest, healthiest bulbs for replanting. These will give you the strongest and most productive crops season after season.

Potato Onion

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