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How to Grow Onions

Few cooks would disagree that the most useful vegetable in the kitchen are onions. What’s more, these are among the easiest to grow in your garden.

They come in a wide variety of colours and have different uses in the kitchen. All varieties will grow and store very well, so you can enjoy the taste of your homegrown onions all year round.

How to Grow Onions

You can grow onions from seed, and if you are an experienced gardener you may well chose to continue in this way. Especially as this method gives you a greater choice of varieties and it’s also the most cost-effective. Unwins sell a wide variety of onion seed that you can choose from.

It is also worth thinking about protecting your crops with companion planting. Our range of Partner Plant seed combinations allow you to grow varieties together to protect from pest attack while also encouraging beneficial insects. Our Parsnip & Onion partner plants are ideal for this.

onion partner plants

However, the quickest and easiest way to grow onions are to opt for for onion sets (small onions). These are specially prepared, ready to plant baby onions that will mature into large, tasty onion globes by mid to late summer. This is the method we want to show you below:

 

Step 1: Sow Onion Seed

Sow onion seeds indoors in January so they are large enough for you to plant out in spring. Sow them in a tray with seed compost about 1cm apart. When the seedlings are a few inches tall you can prick them out and transplant to a bed. Gently push each transplanted seedling into the garden about 10-15cm apart to allow for growth.

 

Step 2: Planting Onion Sets – Soil Preparation

Onion sets are ideal for planting in spring or autumn. November is a great time to get the last minute planting of onions in, especially if its quite mild still.

Choose an open and sunny site. Dig over the soil until it is crumbly and easy to work.

Dig in some New Horizon Vegetable Compost  to improve the soil and add a dressing of Growmore to the soil.

new horizon all vegetable compost 50l lifestyle

Step 3: Planting Onion Sets

Gently push each mini onion bulb, or transplanted seedlings into the prepared soil until just the very tip is protruding.

Leave at least 10cm (4 inches) between each bulb to allow room for the onions to grow.

Plant in rows for convenience and leave at least 30cm (12 inches) between rows.

 

Step 4: Caring for Your Onions

Weed between the onions and keep the soil moist until they have established.

Onions are shallow rooted, so take care when weeding not damage them.

It is also worth placing over some fleece or netting over your onions as birds do like to uproot the bulbs0

Step 5 : Harvesting

You should harvest your onions as soon as they are big enough to use.

In mid to late summer when the leaves have started to yellow and die off, place a fork under the swollen bulbs and lift them out so that the sun can ripen the base of the bulbs.

When the foliage has died off completely, string them up for winter use and store.

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