Mustard greens growing profile.

Mustard greens Companion Plants

What may help, what can compete, and where the evidence is still uncertain.

Mustard greens Brassica juncea

Cool-season vegetable in the cabbage family. View plant profile →

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Quick answer

Evidence supports or conditionally supports growing mustard greens with Cabbage. 1 popular pairing has no verified relationship, which is not the same as safe or harmful.

Every status below has a direction, mechanism, context and source. "No verified relationship" means we looked and found nothing usable; the planner then evaluates spacing, light, water and timing normally. How we classify evidence →

Conditional benefit (1)

Positive only when the stated conditions match; otherwise informational.

CabbageBrassica oleracea var. capitataConditionalTrap crop · flea beetles, cabbage white caterpillars Mustard greens may affect CabbageSpring–Fall · perimeter · Border rows.Tier C Review: August 15, 2026

Why?

Claim. Mustard is used on farms as a perimeter trap crop for several brassica pests because it is more attractive than cabbage; the practice depends on early planting and destroying pests in the trap rows.

Mechanism. Pest preference for mustard over cabbage.

Studied in. Farm-scale guidance and trap-crop reviews. (field)

Conditions. Sow mustard 1–2 weeks before the cabbage. Border rows. Both plants must be present at the same time.

Management. Monitor and treat or remove infested mustard.

Applies when. Large beds with a clear perimeter.

Limitations. In a small garden, mustard more often simply hosts the same pests.

Evidence. Tier C: Indirect evidence: greenhouse or pot work, a related crop or species, or credible extension guidance with important uncertainty. (extension synthesis).

Sources. Sustainable Agriculture Research and Education (SARE) 2009; Shelton 2006

Reviewed August 15, 2026 by Garden Planner editorial team (pending independent horticultural review). Record mustard-greens--cabbage--trap_crop v1. Request a correction.

No verified relationship (1)

Zero score and an honest unknown state. Spacing, light, water and timing are evaluated normally.

No verified relationship: we did not find a source that establishes a benefit or harm for these pairs. This is not the same as "compatible".

OnionAllium cepaNo verified relationshipOther Mustard greens and Onion affect each other (mutual)Spring–Fall · arrangement unspecifiedUnknown Review: August 15, 2026

Why?

Claim. We did not find a source that establishes a benefit or harm between mustard greens and onion.

Mechanism. None documented.

Conditions. Planted together Both plants must be present at the same time.

Applies when. The planner evaluates spacing, light, water and timing normally.

Limitations. No relationship documented.

Evidence. Unknown: No source meeting the inclusion rules. (none).

Sources. University of Minnesota Extension 2023

Reviewed August 15, 2026 by Garden Planner editorial team (pending independent horticultural review). Record mustard-greens--onion--other v1. Request a correction.

Example layout for mustard greens

Documented arrangement with Cabbage: perimeter. Border rows. Sow mustard 1–2 weeks before the cabbage.

Worked example based on the record, not a photograph of a trial.

**Side view of mustard greens (30–60 cm) beside typical companions, showing canopy, support, shade and access.**

When these companions overlap

Bed occupancy in Portland, Oregon (estimates). A relationship only matters while both plants are present.

Mustard greens

Cabbage20 wk overlap

Onion24 wk overlap

Overlap in weeks
Cabbage	20 weeks
Onion	24 weeks

Crop rotation guidance

Rotation is about what occupied the bed in previous seasons and is calculated separately from the live companion relationships above.

Rotate mustard greens on a 3-year cycle with other cabbage family crops (Cabbage, Broccoli, Cauliflower, Kale, Brussels sprouts). Shared risks: clubroot, cabbage root fly, cabbage white caterpillars.

Crop rotation hub · Brassicaceae family page

Physical and resource fit

No significant light, water, pH or sprawl conflicts with the listed companions at recommended spacing.

Fit checks come from plant attributes and apply even when a pairing has a positive claim.

Community observations (anecdotal)

These reports come from gardeners and are not reviewed evidence. Results vary with soil, climate and practice. Community data never changes an evidence tier or a planner score.

Reports for mustard greens: 0 (community submissions open in a later phase; drafts are stored only on your device).

**Community-submitted photo area (moderated) with context fields: region, season, layout, varieties, outcome.**

Record an observation

Evidence summary and sources

Using trap crops to reduce pests — SARE / USDA, 2009 (guidance)
Concepts and applications of trap cropping in pest management — Annual Review of Entomology, 2006 (synthesis)
Companion planting in home gardens — University of Minnesota Extension, 2023 (guidance)

Reviewer: Garden Planner editorial team (pending independent horticultural review). Status counts on the Companions A–Z page are derived from these records. Corrections.