Can you plant onions and asparagus together?

Charts say no. Nobody has tested onions with asparagus, as far as we could find. The chart entry we found cites no source.

Why we can't give a firm answer

Garden charts advise against it. 1 garden chart entry says to keep them apart. It cites no source. Charts pass on gardening tradition; they are not tests.
List of companion plants (uncited entry) (Wikipedia)

What to plant with onions and asparagus

Good neighbours of both, best tested first.

TomatoWith onions: Better soil and nutrient uptakeWith asparagus: Recommended by garden charts, not tested
DillWith onions: Draws in pest-eating insectsWith asparagus: Recommended by garden charts, not tested

How each one was tested, with the evidence

What to keep away from onions and asparagus

PeaWith onions: Garden charts advise against it, not tested
PotatoWith asparagus: Garden charts advise against it, not tested
GarlicWith asparagus: Garden charts advise against it, not tested

The evidence in detail

For readers who want to dig in: every chart entry, study and yield trial behind the answer above, with the numbers.

Tradition, research and yield trials

Tradition

Bad

avoidgood

1 chart entry: 0 recommend, 1 advise against.

0 cited, 1 uncited.

Research

No papers found on this pair.

Yield trial

No intercropping yield trial.

Untested folklore

Companion plants for both onions and asparagus

Plants that are good neighbours of each. Biggest harvest gain first; each cell links to the evidence for that pair.

Plant	With onions	With asparagus
Tomato	Better soil and nutrient uptake and bigger combined harvestMixed results on soil and nutrientsField trial, 7 studies. Charts: not listed.Evidence for onions and tomatoes	No trial foundNot tested. Charts: recommend.Evidence for asparagus and tomatoes
Dill	Draws in pest-eating insectsField trial, 1 study. Charts: recommend.Evidence for onions and dill	No trial foundNot tested. Charts: recommend.Evidence for asparagus and dill

The evidence, with sources

TraditionBad1 entry

Badadvises against
Asparagus: avoid Onion
List of companion plants (uncited entry) (Wikipedia)

Plan a bed with onions and asparagus

All neighbours of onion and of asparagus, or every pair at once in the companion planting chart.

Have you grown onions and asparagus together?

Tell other gardeners what happened: spacing, pests, harvest, or ask a question. Reader notes are not checked by us and do not change the verdicts on this page.