When to Plant Onions in the UK

Onions are usually planted in spring in the UK, although some varieties can be planted in autumn for overwintering. Planting onions at the right time helps them develop strong roots and healthy bulbs.

Most gardeners grow onions from sets, which are easy to plant and reliable.

Soil should be workable and not frozen or waterlogged.

Planting onion sets in spring

Spring is the most common time to plant onions.

Onion sets are usually planted between March and April, once the soil begins to warm.

Planting too early in cold, wet soil can slow growth.

Planting overwintering onions

Some onion varieties can be planted in autumn, usually around September or October.

These grow slowly through winter and continue growing in spring.

Overwintering onions are ready to harvest earlier in the year.

Soil and weather conditions

Onions grow best when soil is:

• loose

• well-drained

• easy to work

Waiting for better soil conditions usually produces stronger plants.

Raised beds often warm faster in spring.

Growing onions in containers

Onions can also be planted in containers with good compost and drainage.

For container advice, see growing onions in containers.

Planning the onion growing season

Planting onions at the right time helps bulbs develop properly during the growing season.

Most onions planted in spring are harvested in summer.

For growing advice, see how to grow onions in the UK.