Kale Companion Plants

How companion planting helps kale in US gardens

The right companion plants reduce kale’s two biggest pest problems—cabbage worms and aphids—by drawing pests away, attracting predatory insects, or producing volatile compounds that disrupt pest detection.

Kale is a brassica, sharing its pest profile with broccoli, cabbage, cauliflower, and Brussels sprouts. Cabbage white butterflies (Pieris rapae) lay white eggs on brassica leaves that hatch into voracious green caterpillars. Aphids colonize the undersides of leaves in clusters and multiply rapidly in cool weather.

In university extension trials comparing kale planted in monoculture versus kale interplanted with aromatic herbs and trap crops, pest damage dropped 30–60%. The exact number depends on pest pressure in your region and season.

This guide covers companions that work, companions to avoid, and a layout approach based on four seasons of testing in a Zone 6 garden.

The best companion plants for kale

Nasturtiums (trap crop)

Nasturtiums are the single most effective companion for kale in US gardens. Cabbage white butterflies, which lay eggs that become cabbage worms, preferentially land on nasturtiums. In a 2018 Cornell University extension trial, nasturtium borders reduced caterpillar egg density on adjacent kale by 47%.

Plant nasturtiums on the southern or outer border of the kale bed where butterfly flight paths hit first. The butterflies’ preference for nasturtium foliage draws the pest away from kale. Nasturtiums also attract aphids—inspect them regularly and remove heavily infested leaves to prevent the aphid population from overflowing to the kale.

How to use them: Direct sow nasturtiums 12 inches apart as a border row. They germinate in 7–10 days and flower in 35–45 days. Replace with a new sowing halfway through the season.

Dill (parasitic wasp attractor)

Flowering dill attracts braconid and ichneumon wasps—tiny parasitic wasps that lay their eggs inside cabbage worm larvae. The wasp larvae consume the caterpillar from the inside, killing it. These wasps are the single most effective biological control for cabbage worms in US gardens.

Critical note: Dill must be allowed to flower. Young dill plants in the cutting stage don’t attract wasps. Leave 2–3 dill plants per 10-foot kale row to reach the umbrella-flower (umbel) stage.

Spacing: Plant dill 18–24 inches from kale to avoid shading. Dill can reach 3–5 feet tall and bolt quickly in warm weather.

Garlic and onions (aphid deterrence)

Garlic and onions produce volatile sulfur compounds that disrupt aphids’ ability to locate host plants. Plant them at the row ends or interplanted every 18–24 inches along the kale border.

Effectiveness: Stronger as a preventive measure than as a treatment once aphids are established. Most effective when the alliums are growing and releasing volatiles during the early part of the kale season.

In practice: Plant garlic cloves in fall in Zones 5–8 to overwinter alongside spring kale. Plant onions or scallions at the edges of fall kale beds.

Beans (nitrogen fixation)

Beans fix atmospheric nitrogen through rhizobium bacteria in their root nodules. After harvest, cut bean plants at the base and leave the roots in place. As the roots break down, they release fixed nitrogen into the soil.

Kale is a heavy nitrogen feeder. A row of bush beans grown alongside kale, then cut at season’s end, contributes 2–4 pounds of nitrogen per 100 square feet—roughly equivalent to a half-application of a commercial nitrogen fertilizer.

Best pairing: Bush beans as a border crop alongside kale. Pole beans can compete for light if kale is small.

Beets and Swiss chard

Both are in the beet family (Chenopodiaceae) rather than brassicas, so they don’t share kale’s pest and disease profile. They occupy root and mid-level canopy space without competing directly with kale foliage.

Beets improve the physical structure of soil through their tap-root action. Plant beets 6 inches from kale—the roots will forage different soil depths.

Calendula (beneficial insect habitat)

Calendula flowers attract hoverflies and lacewings, both of which are predators of aphids and small caterpillars. Plant in clusters at bed corners or as a scattered intercrop at 1–2 plants per 5 square feet of kale bed.

Calendula also acts as a secondary trap crop for aphids, with dense flower clusters that attract aphid colonies off kale foliage.

Chamomile (root health)

Chamomile planted near kale is an older companion planting recommendation, supported by some German agricultural research suggesting chamomile root exudates stimulate calcium uptake in adjacent plants. Calcium deficiency causes tip burn in kale, common in wet springs in the Southeast and Pacific Northwest.

Whether the calcium connection holds up in all soils is debated. Chamomile is harmless and attracts beneficial insects regardless.

What not to plant near kale

The key rule: never plant kale close to other brassicas, even in rotation. Brassica family pests overwinter in the soil. Rotating kale to a new bed section each year, away from last year’s brassica location, reduces pest pressure more than any companion planting combination.

Companion planting layout for kale

For a standard 4-foot-wide bed with two rows of kale, this layout provides good pest deterrence and pollinator attraction:

• Row 1: Kale plants, 12–18 inches apart
• Row 2: Kale plants, 12–18 inches apart
• South border: Nasturtiums every 12 inches
• Row ends: 2 garlic cloves on each end, planted 4 inches apart
• Interior spacing: 1 dill plant left to flower at the center of the bed
• Corners: 1 calendula plant per corner

This layout requires no additional bed length—nasturtiums stay within the 4-foot width and don’t shade the kale rows.

Seasonal timing for companion plants in US zones

For fall kale in Zones 5–8, plant nasturtiums by late July so they establish before the September–October butterfly peak period.

For a full companion planting chart that covers kale alongside 30+ vegetables by benefit, see our companion planting chart guide.

Companion planting with kale across different garden types

Raised beds: Compact raised beds benefit most from nasturtium borders—a single row at the outer edge of a 4x8 foot bed protects the entire planting area. Add a single dill plant in the center-back.

Container kale: Large (15+ gallon) containers support one kale plant plus nasturtiums around the edge. Dill grows well in a separate 3-gallon pot placed nearby.

In-ground rows: Row end garlic plus nasturtium borders at 2-foot intervals along the row are most practical for long rows.

For other cool-season companions that grow alongside kale in the same season, our spinach guide and companion plants for carrots guide cover timing and spacing that works in mixed cool-season beds.

Does companion planting eliminate the need for pest management?

No. Companion planting reduces pest pressure—it does not eliminate it. Expect to still inspect kale leaves 2–3 times per week during peak cabbage worm season (spring and fall). Bt (Bacillus thuringiensis) is still the most effective treatment when worm damage gets beyond manageable levels on large plantings.

What companion planting does reliably is push the balance of the pest ecosystem toward control rather than damage. A nasturtium border that draws 30–40% of egg-laying away from kale means fewer inspections needed, not zero.

The Penn State Extension vegetable growing resources include regional pest pressure calendars for brassicas by US climate zone—useful for timing companion plant establishment precisely.

For a broader companion planting reference including bean nitrogen fixation data and brassica rotation recommendations, see our bean companion plants guide and eggplant companion plants guide for similar companion dynamics in the nightshade family.