Onions are a versatile crop, coming in a range of colours for different uses in the kitchen. Onions are a staple in a huge variety of dishes, from hot curries to soups, salads and tarts. All onion varieties are easy to grow and they store well, too, so you can enjoy home-grown onions all year round.
How to grow onions
You can grow onions from seed, but it’s much easier and quicker to grow them from sets (small onions). Most are heat-treated, meaning they’re less likely to bolt (produce flowers), which stops the onions bulking up. One small onion set grows into one larger onion. Plant these in autumn or spring, 10-15cm apart in well-prepared, moisture-retentive, fertile soil in full sun. Keep the area weed free and water in dry periods. Harvest the onions when they’re big enough to eat or the foliage has turned brown and started to wither.
How long do onions take to grow?
Onions require 90-100 days to mature from seed, which is around four months. From sets, onions are ready to harvest after around 80 days, or just under three months.
How to sow onion seed
Sow onion seed indoors as early as January, so they are large enough to plant out in spring. Sow seed in a pot or tray of moist seed compost, about 1cm apart. When the seedlings are a few inches tall, prick them out and transplant into fresh, peat-free multi-purpose compost. Once established, transplant seedlings into the garden, 10-15cm apart.
How to plant onion sets
There’s no need to soak onion sets before planting. Plant them 10-15cm apart, allowing 30cm between rows. Plant them just below the soil surface, with just the tips showing, in moisture-retentive, fertile soil, ideally with plenty of well-rotted organic matter such as garden compost.
