How to Grow Onions

how to grow onions wellLearn how to grow onions as they are a popular crop to crop in most allotment gardens.

There are many different types of onions that you can grow and it is worth taking the time to explore the different options or try new varieties each year.

The most popular and easiest to grow are sets.  Usually, you can easily get the brown red and white onions locally.  If you want the huge ones you may need to go to a specialist.  When learning it is best to start with sets as these are easiest and quicker to do.

While onions are not that expensive to buy in the shops it is well worth growing your own if you use a lot of them.  You can store onions for a reasonable amount of time or chop them and freeze them.

How to Grow Onions


Easy to Grow 

Onions are a very useful and versatile vegetable that are easy to grow.

Quick Tips: If you only have a small plot and limited space you may want to try them or consider shallots as an alternative as they take up less room for the amount of return you get.

Growing and Sowing Onions

Although you can buy seeds for growing onions they are easier and quicker to grow from sets.


Onion sets can be planted in the autumn from September to about November or the spring depending on your preference and the variety.  Most people refer the spring as onions overwintered can rot if it is a particularly wet season and not everyone wants to be on the allotment over the winter months.

If planting in the spring plant in April or as your set recommends.  It is best to plant them all together as you can store them until needed.  Though if you prefer you can stagger through the season although it is not necessary with onions to do this.

A full Video Guide on how to plant and grow onions

Onion Types

While you can use you onions how you want different onions are best for different things.  Red onions are great for salads as they are sweeter while brown/yellow ones are better cooked although they are a good all-rounder.  White onions are also great in salads and are quite sweet if you sauté them

Pests and Diseases

Pigeons and other birds are a particular problem for freshly sprouting onions.  Net them or use criss-cross bamboo canes over the onions to prevent them from being lifted.


Harvesting is easy.  Once the bulb is big enough simply pop something carefully under it and lift.

Autumn planted onions can be ready as early as May while spring planted ones will be lifted from July onwards.  Though if you want to extend the season smaller ones can be lifted sooner.  Once the greenery starts to wilt then the onion is ready.

Quick Tip:  The leaves will look ready long before the bulb fills out so give it time.  Onions can bolt in particularly dry weather.  If this happens then they will need to be pulled up.

Drying Your Onions

Once you have lifted your onions they will need to be dried ideally in the sun for a few days.  Many people just leave them on the soil to dry out while others prefer to put them on onion racks to let the air circulate.

Once ready they can be cleaned up and their foliage can be neatened and then they can be stored in a dry and cool place.  (Note:  if kept too warm they can sprout)


The red onions are sweeter and great for salads while the other ones are great for stews, casseroles, curries etc.