Alliums — onions, garlic, shallots, leeks, chives — earn their place as companions through sheer smell. That oniony pungency masks the scent of nearby crops and muddles the pests hunting by nose, which is exactly why the carrot-and-onion pairing is the most famous in the whole of companion planting: each one's scent helps hide the other from its particular fly.
They're also wonderfully space-efficient, growing slim and upright with little canopy, so they slot in around almost anything. The one group to keep them away from is the legumes — beans and peas — whose growth allium root secretions can genuinely check. Other than that, alliums are easy, willing neighbours all over the plot.
Grow these alongside
The classic pairing — onion scent confuses carrot fly and carrot scent confuses onion fly. Grow in alternating rows.
Easy-going neighbours that don't compete with the slim, upright alliums for space.
Quick low leaves that fill the ground between allium rows before the bulbs swell.
Pungent alliums help confuse the pests hunting brassicas by smell.
Chives and garlic tucked around a strawberry bed are said to help keep mould and pests off the fruit.
Keep these apart
Allium root secretions can stunt the growth of legumes — the one pairing to always keep in separate beds.
A long-lived crop that resents the competition; give alliums their own ground.
Traditionally said to clash with onions — easy enough to keep apart.
Flowers worth tucking in
The blooms that pull pests away and bring in the bees — beauty that earns its keep.
An old companion said to improve the growth and flavour of onions nearby.
Bring in hoverflies and brighten the edge of the bed.
Common questions
What grows well with onions and garlic?
Carrots are the classic partner — the two scents confuse each other's flies. Beetroot, chard, lettuce and brassicas all make easy neighbours, and a ring of chives or garlic around strawberries is said to keep pests and mould off the fruit.
Why plant carrots and onions together?
Carrot fly and onion fly both hunt by smell. Grown in alternating rows, the onion scent masks the carrots and the carrot scent masks the onions, so each crop helps hide the other. Pair it with a fine mesh barrier for the most reliable protection.
What should not be planted near onions or garlic?
Keep alliums away from beans and peas — their root secretions can genuinely stunt legumes. It's also worth keeping them clear of asparagus and, by tradition, sage.
Can I plant garlic with other vegetables?
Yes — garlic is one of the best companions there is. Its scent helps protect carrots, brassicas and strawberries from pests, and it takes up so little room you can tuck cloves in around the edges of almost any bed except where beans and peas are growing.
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The complete companion planting guide →