Onions are a staple vegetable in our house, we eat tonnes of them. Most of my cooking begins with a diced or sliced onion of some description; if I’m making soup, chilli, curry, bolognese or chutney, the underrated onion helps build the background flavour to most of the dishes we enjoy eating. They’re easy to grow and store well for months, making them a brilliant vegetable to grow at home.
seeds or sets
Onions can be grown from seed. I have tried it before and it’s not difficult to do but the process is more involved and takes a little longer to gain an established harvest. Traditionally, onions are grown from ‘sets’, a little ready-grown baby onion bulb which can be bought from most garden centres or online seed catalogues at the beginning of Spring. The advantage of growing from a commercially bought set ensures your crops are virus free and yields more reliable.
Seeds can be sown indoors throughout January and February, or outside during March and April. Sets can be started off in module trays indoors during February or planted directly outside in March and April. Overwinter varieties can be planted outdoors in September and October for an early harvest the following year.
planting & care
Choose a sunny, open site to plant your onions. They like a well-drained, weed free soil. I use a dibber tool to make a little hole in the surface of the soil and place the onion set into it at a depth of 2cm.
Try not to bury the entire bulb. Leave a little tip poking through the surface and firm the soil around it with your fingers. Plant sets 5cm-10cm apart, or leave enough space to weed around them with a hoe.
Ideal row spacing is 20-30cm, but if you’re short on room they can be planted in clumps to maximise the growing space. Mark the rows with seed markers and cover with garden fleece until green shoots appear. The fleece isn’t essential but will offer extra protection from birds and pigeons until the onions have laid down their roots.
Weed regularly to allow the onions to swell and develop. Don’t over water as they are prone to mildew and rot. If flowers stems form, cut them off at the base straight away as the plant will go to seed and become woody and inedible.
harvesting & drying
Harvesting takes place from June to September. The leaves of the stem will begin to turn yellow and collapse; they have their own way of letting you know when they are ready to be picked! Choose a sunny day to do this.
Begin by gently loosening the soil around the roots and lift the bulbs carefully, trying to keep the stem intact. Lay the onions on their side to allow them to dry in the sunshine for a few hours. If it’s wet, bring them undercover, spread out on newspaper to let the moisture dry. Ideally transfer to racks (if you have some) in a sunny, well ventilated space.
A greenhouse, conservatory or windowsill is perfect. Turn the bulb upside down leaving the stems dangling down through the slats for 2 to 3 weeks until the leaves are completely dry and crispy with no moisture left in the stem whatsoever. You’ll notice the skins around the bulb tighten and go papery thin as they begin to dry out. They will turn a rusty orange colour. This process, known as curing, is essential to ensure the onions store well for future months.
hanging & storing
Once the onions have cured they can be stored tied up in bunches, hanging in netted sacks or laid out in wooden trays. I always plait mine in a traditional onion string and have them hanging in the kitchen.
Whichever method you choose, make sure they are stored in a cool, dry place like a shed, cellar or garage. Check them regularly and discard any onions that have signs of mould or rot. They should keep for 8 to 10 months, unless like us you’ve eaten your way through the supply before the following year’s crop is ready.
plaiting onion strings
- Sort the cured onions into sizes; small, medium and large.
- Take three large onions and tie a length of twine about 50cm long around the base of each stem.
- With one stem laid out in the centre, lay another stem over it, draping the dried leaves to the left.
- Repeat with the third stem, draping it to the right.
- Hold the bunch tight between your fingers and thumbs as you continue to drape additional onion stems into the plait, criss-crossing as you go.
- Add medium sized, then smaller sized onions to the braid as it continues to grow.
- The onions should interlock with each other, sitting in the next available space within the plait.
- Knot and tie off the end of the twine and make a hanging loop. Volia, c’est simple!
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