How To Grow Tree Onions In The UK
For Unusual Food You Grow at Home

Propagating Onions from Top Sets

Small onions that are used for propagation are called sets. When they are produced on the flower stem they are usually referred to as "top sets" or "bulbils".

Egyptian Onion Top Set Bulbils
Young Tree Onion Bulbils on a First Year Plant
This Spring grown plant is already producing its next generation

Winter Hardy

Once established, tree onions are Winter hardy, drought tolerant and pretty much self reliant. You can leave them to establish a decorative bed or collect them as you would spring onions for years to come

Growing From Mature Top Sets

When the bulbils change colour and form a slightly tougher outer skin then they are ready to be harvested for planting. Often, they will have had a head start and already producing green shoots but that isn't necessary as they will grow from dormant bulbils too

Bulbils Bought Online or Acquired from a Fellow Gardener

If you buy tree onion bulbils off ebay, amazon or similar outlet then it's likely that your small bulbils have been stored for several weeks or months. This shouldn't be a problem as they store well. For this planting exercise we'll start with bulbils that have been picked and stored for about a month to six weeks

Freshly Harvested Tree Onion Bulbils
Tree Onion Heads After Harvesting
Mini Bulbs of Various Sizes
Tree Onion Bulbils Ready for Planting
The smallest tree onion bulbils have already been planted
Here are some that are being stored
Planting Tree Onion Bulbils

Tree onions do best in a moist, free draining "soil". I typically use a 1:1:1 mixture of garden soil, sharp sand and any cheap compost. To this, I add a small amount of slow release fertiliser and mix well

Onions get their flavour by producing a variety of sulphur compounds, so a small amount of calcium sulphate (gypsum) or sulphur containing fertiliser during the growing period can also be beneficial

Tree Onion Bulbils - About 2 Weeks After Planting
Some bulbils can take a while to actively start growing
Here are small bulbils on the left and large bulbil on the right about 2 weeks after planting

Growing from Small or Large Bulbils

The very small bulbils look quite grass-like as they first start to grow while the larger walking onion bulbs can seem to get off to a flying start; producing a much more vigorous plant

Eventually the smaller ones will catch up and produce a similar sized plant but will take a little longer to get established

Over Wintering In The UK

Egyptian Walking Onions - Tree Onions are Winter hardy and should be able to cope well with the UK Winter temperatures. However, while you are establishing a bed of tree onions; it would make sense to provide some Winter protection such as a greenhouse or cold frame. If this is not possible, try to cover the bulbs in a layer of tree mulch as insulation to reduce the effects of frost and minimise casualties

Damp Winter Weather
Winters in the UK can be particularly damp. This can lead to rotting if plants sit in water-logged soil, so make sure to provide a free-draining soil or growing medium. That's about it for part one. I'll develop this article with more photos as the seasons progress

Here`s a brief one page guide for you to print:Tree Onion Cultivation