How To: Grow Onions

Onions are a popular staple in many kitchens around the world and are incredibly versatile as there are many different varieties. Onions can be used in a wide range of dishes from soups to stews, salads and sandwiches. Not only are they flavoursome and provide a wonderful base for many dishes, but they are also packed with nutrients and minerals. Let’s find out how to grow onions in your garden.

How To: Grow Onions

Varieties of Onion

As mentioned above, there are many varieties of onions including white, yellow, red and sweet onions, each with its own set of qualities. The type of onion you can best grow in your garden will depend on the climate in your area. For example, yellow onions will do best in cooler temperatures whereas red onions are more suited to warmer temperatures.

Planting Your Onions

These hardy vegetables will require a well-drained soil that is rich in nutrients; it’s worth amending the soil with compost or well-rotted manure before planting. They also prefer soil with a pH level of around 6.5 – 7.0 so it is worth testing this before planting. 

Onions can be planted from seed or from sets. Sets are small bulbs that are planted directly into the soil, whereas seeds are started indoors and transplanted into the garden later on. Sets are the ideal choice for beginners as they require little planning or preparation, and take less time to mature than seed onions. 

If you are planting from seed, plant them indoors around 8-10 weeks before the last frost and transfer them into the garden when the danger of frosts has passed.

Onions being planted into soil

Growing Your Onions

When planting sets, ensure the pointed end is facing upwards, and the flat end is down towards the ground. When transplanting seed onions, space them 4” apart. Once covered with soil, water them thoroughly and add mulch around the base of the plants to retain moisture and prevent weed growth.

In terms of growing, onions will require full sun and a good consistent supply of water to ensure healthy growth.

Harvesting & Storing Onions

You can tell when onions are ready to be harvested when the tops begin to yellow and fall over. This can be from June to September, depending on when you planted them and if you used sets or seeds. 

Use a garden fork to gently lift the bulbs out of the soil and lay them in a sunny area to dry. The drying process is called “curing” and can take up to two weeks – this toughens up the outer skin which helps keep them fresher for longer. After they have cured, the tops will be completely dry and the onions will be ready to be stored. They are best kept in a cool, dark place such as a cellar, basement or pantry. You can hang or string them up and they will last several months in the right conditions.

Growing onions in your garden is a great way to save money and encourage scratch cooking at home. Speak to one of our staff members at Holt Garden Centre who will be happy to suggest some different varieties of onion for your garden and give advice on how best to care for them.

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