How to grow multiplying onions
What are they?
These onions have various names – walking, tree, Egyptian, top set, multiplying. They grow from bulbs rather than seeds and a single bulb will multiply and grow 5-10 bulbs through the year. They can be harvested by pulling off individual bulbs rather than needing to lift the whole bunch at once.
· These are a perennial vegetable. Once you have a few bulbs you’ll always have them in the garden. I’ve had them for several years. They’ve moved from pots to garden beds, back to pots and into different beds with no problems.
· Taste – similar to a shallot.
· Size – bigger than a spring onion, smaller than a regular brown onion.
· More about the name – they are called multiplying onions because of the way they grow – one bulb will multiply to five, six or ten bulbs through the year depending on growing conditions. Walking and top set refers to the way they can grow a set of bulbets or topsets at the end of the season which then touch down on the ground. These can regrow and in theory the onion can ‘walk’ across the garden if this process repeats.
Growing multiplying onions
Soil condition and location
· They grow well in pots
· Full sun is preferable
· Like most vegetables they will do best in free draining soil – sitting in water will cause them to rot.
· This can be done any time in New Zealand although best not in the middle of summer when it’s hot. March is ideal. Mine grow in Auckland so I haven’t experienced how they will grow in the South Island. In cold areas of the US they grow – they avoid planting them when new growth would be affected by frost or extreme cold.
· Purchased bulbs may come separately or clumped together – gently tease clumps apart. Leave the dry papery skin on the bulbs for planting (remove for eating!).
· Plant bulbs individually 10-20cm apart root point down into the soil. How far apart will depend on how much space you have and how often you’ll be harvesting the bulbs. If you frequently take off bulbs the clump won’t get overly big. They don’t mind being crowded.
· The bulb only needs to be pushed into the soil a few mm deep with some sitting above ground.
The individually planted bulbs will multiply to form more bulbs over one-two years. They will grow green leaves at the top of the bulbs and later form a bulbets/topset from the middle of the cluster of bulbs. The leaves and topsets die back at the end of the season.
They aren’t deep rooted and sit partially on top of the soil. (In cold areas these may do better being further into the soil for protection in winter).
• Keep moist but don’t overwater. Like a lot of plants, they don’t like to sit in wet soil.
• Feed to ensure large sized bulbs.
• Aphids can be a problem if let to multiply as they will suck the goodness from the plants so eliminate them when they start to appear. While some people say to squash them or squirt them with the hose they will mostly just drop to the ground and come back when your back is turned. I’ve had some success with spraying with a garlic, chilli, soapy solution.
• They haven’t been affected with rust like my garlic and leeks.
• Remove the topsets/bulbets when they dry and fall over and touch the ground if you don’t want them to regrow.
• Removing the topsets/bulbets as they grow will supposedly encourage the plant to grow bigger bulbs. I haven’t done this but assume this will be the case.
Harvest and replanting
· Tease bulbs off the main plant for eating as required
· Lift the whole plant after 2-3 years if the clump has got too big and it’s not growing as well. Divide the bulbs when the bulbets/top sets and leaves have died back and replant.
· The bulbets can also be planted if you want more plants. These may grow when they touch down on the soil.
· Use the main bulbs as you would a shallot. Peel the outer dry skin first.
· The topset bulbets can also be eaten though they are small and fiddly. Use these to flavour stocks and soups.
· The hollow green leaves can be eaten like a chive or spring onion.