An heirloom onion with a delightful, rich flavour. They are also more cold hardy, resistant to pests and disease than common onions making them very valuable to home gardeners. They readily divide and can easily be broken up for replanting or enjoying. They don’t flower as readily as Shallots which is good news for storage as they tend to store better. (They aren’t usually grown commercially as they prove difficult for machinery). One bulb can increase to up to 15 in a season.
They grow as you would Shallots, but have a much more of a robust flavour, more similar to onions.
Common names include Pregnant Onion, Underground Onion and Mother Onion. Botanically they are Allium cepa (Aggregatum Group).
Potato Onions are easy to grow, simply requiring a well drained soil and a sunny spot. It is a good idea to keep shallots moist during growth, they have a short root system so regular watering is important for good bulb growth. It is a good idea to grow in a rich, friable soil and add a little fertiliser for best production. Plant the bulbs just under soil level and space around 20-40cm apart.
You can companion plant you Potato Onions with lettuce, cabbage, beets, carrots, mint, thyme, sage, strawberries and tomatoes. They shouldn’t be teamed with beans or peas.
The old adage is to plant on the shortest day and harvest on the longest as they take 90-120 days to mature. In warmer areas they can be planted and harvested a bit earlier. You should pull the bulbs before flowering, as the green shoots begin to bend and wither. Dry them in a well ventilated area for two to three weeks before separating then storing or feasting.
If you can resist, try and keep a couple of the bulbs back for replanting next season. In ideal conditions, Potato Onion bulbs will store well for up to a year.
Supplied as: Bulbs
Summer to autumn
Cool to Mediterranean
Unavailable in WA, TAS