What it needs & gives back
↓ Needs
↑ Gives back
Companions
Cabbage
Onions can deter some cabbage pests.
Asparagus
Onions are said to deter asparagus beetles.
Tomato
Onions are often planted near tomatoes to deter pests.
Carrot
Deters carrot rust fly.
Lettuce
Onions can deter some pests of lettuce.
Hamburg Parsley
Onions can deter some pests of parsley.
Broccoli
Onions can deter some pests like aphids and cabbage worms.
Pepper
Onions can deter some pests.
Rhubarb
Onions are sometimes planted near rhubarb to deter pests.
Parsley
Can help deter onion flies.
Broad Bean
Can help deter aphids from broad beans.
Daubenton kale
Onions can help deter some pests of brassicas.
Beetroot chard
Onions are good companions.
Turnip
Onions are said to deter some pests of turnips.
Swede rapeseed
Onions are said to deter some pests of Brassicas.
Parsnip
Onions are said to deter carrot rust fly, a common parsnip pest.
Celery celeriac
Onions may deter some celery pests.
Brussels sprouts
Onions are said to deter some pests of Brassicas.
Kohlrabi
Onions are said to deter some pests of kohlrabi.
Kale
Onions can help deter some pests of kale.
Salad rocket
Onions can deter some pests.
Winter savory
Can improve growth and flavor.
German chamomile
Believed to improve growth and flavor of onions.
Keep apart from
Through the year
Emergence
Seeds germinate and seedlings emerge when soil temperatures reach 5 C or above.
Flowering
Flowering is triggered by long days after a period of cold temperatures (vernalization).
Fruiting
Fruit (seed heads) develop after flowering.
Harvest
Bulbs are typically harvested in late summer when tops begin to fall over.
Dormancy
Plants enter dormancy with the onset of cold temperatures and first autumn frosts.
Senescence
Foliage dies back with the first autumn frosts.
Timing is relative to your local season (temperate Northern Hemisphere).