Onions and garlic

Onions and garlic

Onions are an essential vegetable for all kitchens and can be grown from small immature bulbs, called sets, or from seed. Spring (salad) onions are immature seedlings and are always grown from seed. Garlic is grown from cloves in a similar way to onion sets.


A sunny spot with well-drained soil is best. When digging over the soil, take out any perennial weed roots and improve the organic content by incorporating some Levington Organic Blend Soil Conditioner. A sprinkling of a general plant food such as Miracle-Gro Gro Your Own Vegetable & Fruit Plant Food will ensure the crop is fed throughout the summer. Rake to a smooth friable surface.

Onion seeds or sets

If you are new to grow your own, then the small, immature onion bulbs, called sets, are the easiest way to get reliable results. Each one forms one full-sized bulb. Simply plant from mid-March to mid-April as detailed below.

The seed route will give you more onions for your money, but good results are more dependent on warm spring weather and the time you have to keep weeds from dominating your crop.

Autumn or Japanese onions are also available. These will give you an earlier crop in summer than the spring-sown/planted onions.

Selecting the varieties to buy

  • Onion Sets: All are good croppers including Sturon, Jet Set and Golden Ball. For red onions try Garnet or Red Baron/Emperor.
  • Onion Seeds: Ailsa Craig and Bedfordshire Champion are traditional favourites.
  • Salad (Spring) Onions: White Lisbon, Eiffel or Ishikuro.
  • Garlic: Wight Cristo is said to be a great English variety, but Lautrec Wight is regarded as France’s finest.

Planting onion sets

Plant sets from mid-March to mid-April where they are to mature. Carefully push them into well-prepared soil or plant with a trowel, so that the tip is just showing, leaving a gap of 10cm (4in) between each set and 20cm (8in) between rows.

Overwintering Japanese onion sets are planted in early to mid-autumn at the same spacing.

Sowing onion seed

When the soil is warm enough in spring (usually March or April) take out a shallow drill 1cm (1/2in) deep (a drill is a shallow trench that you sow seed in). Sow the seeds thinly and then cover with fine soil and water in.

Seed of overwintering Japanese onions is sown in late summer at the same depth and spacing.

Planting garlic cloves

Break up the bulbs into individual cloves and plant in autumn or in February/March. Garlic planted in autumn usually produces better and bigger yields than that planted in spring - but make sure you choose a suitable overwintering variety.

Gently push the cloves into the soil, so the tip is just below the soil surface, leaving a gap of 15cm (6in) between each clove and 20-30cm (8-12in) between rows.

Thinning onions

Salad onions don’t normally need thinning, just pull and eat. Bulbing onions grown from seed need space to expand, so carefully pull out overcrowded seedlings to leave 10cm (4in) between each plant.


Keep weeds under control throughout the growing season and water only when the weather is really dry.


When the foliage start to turn yellow in late summer for autumn-planted onions or August/September, carefully lift the bulbs and dry for 7 to 21 days under cover. Use bulbs/cloves first that are soft, damaged, spotted or have thick necks. The rest can be stored in an airy place in net bags, tights or tied to cord to make an onion rope.

Click here to learn about growing shallots.