Onion

Onions in Barnhill

Allium cepa

A hardy allium for UK gardens, usually grown from sets for the easiest crop or from seed for more choice. It needs free-draining soil, steady weeding and a careful cure before storing.

Height45cm
SunlightFull Sun
WaterModerate Water

Growing Guide

Step-by-step instructions for growing Onion

Planting Calendar

TransplantLater
J
F
M
A
M
J
J
A
S
O
N
D
HarvestLater
J
F
M
A
M
J
J
A
S
O
N
D
MaintenanceNow
J
F
M
A
M
J
J
A
S
O
N
D
  1. Prepare the Bed

    27 Feb – 14 Mar

    Work the soil from 27th February - 14th March, making sure it drains freely and has a fine tilth. Mix in compost or well-rotted manure, but avoid fresh manure, which encourages soft growth and poorer bulbs.

  2. Plant Sets

    30 Mar – 13 Apr

    Plant sets from 30th March - 13th April, with the tips just showing above the soil. Space them apart in rows apart, then water in thoroughly straight away.

  3. Keep Weed Free

    6 Apr – 4 Aug
    every 3 weeks

    From 6th April to 4th August, hoe between rows lightly and hand weed close to the bulbs so they do not get crowded out. Water during dry spells while the bulbs are swelling, and keep the soil evenly moist rather than soggy.

  4. Lift and Cure Bulbs

    4 Aug – 3 Sept

    Lift bulbs from 4th August - 3rd September when the tops yellow and fall over. Dry them in a warm, airy place for before storing, then trim off roots and loose tops once they are fully cured.

Companion Plants

Tap a plant to see why it works (or doesn't) with Onion.

Good companions

Plants to avoid

Why companion planting matters

Companion planting can deter pests, improve pollination, and make better use of space. Some plants confuse pests or attract beneficial insects; others improve soil or offer shade to neighbours that need it.

Suggested Varieties

Popular varieties of Onion to consider

Sturon

A dependable maincrop onion with good storage qualities and firm, globe-shaped bulbs.

Red Baron

A reliable red onion with good colour and a steady crop from sets or transplants.

Senshyu Yellow

A well-known overwintering onion that can be planted in autumn for an early summer harvest in mild UK gardens.

Centurion

A widely grown, high-yielding set onion with good tolerance to bolting.

Also in nearby towns

See how Onion timing shifts in other towns with different frost dates.