Onion

Keep onion sets free from weeds as grass and weeds tend to compete for nutrients and moisture. Side apply fertiliser during the season if need be.

Try and keep the moisture levels in the soil as consistent as possible – applying mulch is often a good idea.

Growing onions from seed can be trickier than growing from established sets, but it is possible, and can often produce more disease resistant plants.

Sow into flats in a soilless medium and keep in a warm place for about a week to germinate.

By our calculations*, you should look at sowing Onion about 28 days before your last frost date .

Onions are often transplanted from sets – this is typically the quickest and most foolproof strategy to grow onions as growing from seed can be problematic. Sets (or bundles) can be purchased from garden stores and over the internet, and typically contain around 60 – 80 plants.

Onions can be planted out as soon as the ground can be worked in the spring. If you are growing to harvest as green onions, seedlings can be planted quite close together as they will be harvested before they reach full size. If growing for mature dry onions, try to plant as far apart as practicable and thin and use as green onions as you go if you misjudge the distances initially. Keeping good distances between plants is very important for achieving good onion bulb size.

Harvest onions when the tops turn yellow and begin to topple over. To dig them up, loosen the soil around each bulb and then lift them up carefully – make sure not to damage as they can rot quickly.

Spread them on a flat surface above the ground and leave to dry out – this will take anywhere from 2 to 10 days if left out side, or 2 weeks if taken inside. Cut the tops, and then store in mesh bags in a cool, well ventilated space.

Onion seeds can be saved by carefully cutting off the flower head (floret) when the seeds have fully developed, and then placing in a paper bag in a cool dry location for a couple of weeks.

These plants have been known to grow well alongside Onion so consider planting:

fruit trees, nightshades (tomatoes, peppers, potatoes, etc), brassicas (cabbage, broccoli, kohlrabi, etc) carrots ¹

• Onion loves Lettuce

  Protects lettuce against slugs.

These plants will not grow well with Onion so avoid planting these within close proximity:

beans, peas, parsley ¹

These problems, diseases and pests are known to affect Onion plants:

rust is a fungal disease which appears as orange pustules on the leaves. This disease is favored by high humidity and cool temperatures. Crop rotation and isolation of different onion family members may help prevent incidence.

• Snails

• Slugs

  A snail without a shell. A mollusc with an elongated, soft body with a shiny...

• Powdery mildew - onions

• Onion maggots

  One of the most destructive pests of onions. White onions are often more susc...

The common name of “Onion” is probably derived from the Latin unus, meaning “one.”

• Onion is said to relieve the pain of dog bites and toothaches.
• The Romans are said to have brought the Onion to England.
• Growing onions in warmer climates tends to produce sweeter tasting onions.

Garden onion, Common onion, Cebolla

Allium cepa Cepa Group, Allium cepa (Cepa Group)

Misspellings: Oignon, ognion, Allium capa, Onions

Our when to plant Onion estimates are relative to your last frost date. Enter your frost dates and we'll calculate your sowing and planting dates for you!

¹ http://en.wikipedia.org/wiki/List_of_companion_plants