Onion Sets

Growing your own onions

The easiest way to grow onions is from sets, although you can also raise them from seed. Taking up very little space in your veg patch, they’re easy to look after and produce delicious crops from summer through to autumn. Provided you allow them to dry, onions are a good vegetable for storing through the winter. 

When to plant onions sets

Plant your onion sets once the soil begins to warm in the spring – from mid-March until mid-April is usually best, but if it’s a particularly cold, wet year, you should delay planting until the ground dries out a little. Onions don’t do well in heavy, waterlogged soils. Some cultivars are suitable for autumn planting during September and October, ready to grow strongly in the spring. Always check the growing instructions before planting.

How deep to plant onion sets

Plant your onion sets so that the growing tips are just visible above the ground and water in. Birds love to pull newly sprouting sets from the ground, so do check your onions regularly in the early stages and replant as necessary. For autumn-planting onion sets, apply nitrogen fertiliser (30z per sq yd) in February to help spur growth during the spring. For more on growing onions and all our other vegetables, head over to our vegetable growing guide.

How to plant onion sets

Plant your onion sets in shallow drills with the roots down and the pointy end up. If your soil is in good condition, you can simply push the sets into the ground so that the tips are visible just above the surface. If planting in heavier soil, use a trowel to avoid damaging the young roots. Sometimes autumn-planting varieties may sprout a little in transit. If that’s the case, trim the ends off with scissors to deter birds from pulling the sets from the ground.