Best Companion Plants for Kale: Practical Guide
Quick answer: Good companion plants for kale include onions, leeks, thyme, dill, cilantro, lettuce, beets, and low flowering plants such as sweet alyssum. These combinations work mainly because they fit kale’s cool-season growing conditions, use space efficiently, or support beneficial insects. Companion planting can help, but it will not replace proper spacing, crop rotation, row cover, or regular scouting for cabbage worms, flea beetles, aphids, and other brassica pests.
Kale is one of the easier brassicas to grow, but that does not mean every plant belongs beside it. Mature kale becomes much wider than a young transplant, and it still competes for water, nutrients, and light. The best companions are plants that fit around kale without turning the bed into a crowded tangle.
It is also useful to separate practical companion planting from folklore. Some combinations have research behind them; others simply grow well together. Both can be useful as long as the reason is clear.
Best Kale Companion Plants at a Glance
| Companion | Why it can work | Best placement | Main caution |
|---|---|---|---|
| Onions | Compact upright growth; alliums may interfere with pest host-finding | Separate row or wide gaps around kale | Do not crowd kale stems |
| Leeks | Compatible cool-season crop with narrow growth | Along a bed edge | Both crops may remain in the bed for months |
| Thyme | Aromatic flowering herb; brassica research suggests possible caterpillar-reduction benefits | Drier outer edge | Prefers less moisture than kale |
| Dill | Flowers support parasitoid wasps and other beneficial insects | North edge or nearby flower strip | Tall plants can shade kale |
| Cilantro | Cool-season herb; flowers attract beneficial insects | Between young plants or at edges | Bolts quickly in warm weather |
| Lettuce | Low-growing crop with similar cool-season timing | Between widely spaced young kale plants | Harvest before crowding develops |
| Beets | Different growth form and cool-season timing | Separate row or wide gaps | Still compete for moisture if packed tightly |
| Sweet alyssum | Small flowers provide nectar for beneficial insects | Bed border | Can reseed freely |
Start With Kale’s Real Growing Needs
Kale prefers cool weather, fertile soil, consistent moisture, and full sun, although it can tolerate some partial shade. Mature plants are often spaced roughly 12–24 inches apart depending on whether you want full-size plants or smaller repeated leaf harvests.
University of Maryland Extension notes that closer spacing produces smaller “baby leaf” plants, while wider spacing produces larger plants. That is an important companion-planting lesson: the amount of room available around kale depends on how you intend to harvest it.
If you want large plants that produce for months, give kale its full spacing first. Add companions only in the remaining space.
Onions and Leeks
Onions and leeks are among the easiest vegetables to place near kale because they grow upright instead of forming a broad canopy. They can share cool-season conditions without heavily shading the kale.
Alliums are frequently described as pest repellents. University of Maryland Extension notes that volatile compounds from alliums can repel some insects or make host plants harder to locate. That gives the pairing more support than many traditional companion claims.
Still, onions should be treated as a useful intercrop rather than a guaranteed shield against aphids, flea beetles, or caterpillars.
Thyme
Thyme is another useful option around a brassica bed. Research summarized by Maryland Extension found reduced caterpillar damage in broccoli when thyme was used as a companion. Kale shares several of the same caterpillar pests, so thyme is a reasonable border plant to consider.
The main limitation is irrigation. Established thyme prefers drier soil than kale. Place it along the edge of the bed rather than directly beside the kale stem where watering is heaviest.
Dill and Cilantro
Dill and cilantro are most useful when allowed to flower. Their small blooms provide nectar and pollen for parasitoid wasps, hover flies, and other beneficial insects.
Kale does not need pollinators to produce edible leaves, so the value here is biological diversity and natural-enemy support rather than pollination.
Keep mature dill toward the north side of the bed in the Northern Hemisphere so it does not shade kale. Cilantro is particularly easy to combine with spring and fall kale because both tolerate cool conditions.
Lettuce
Lettuce is a straightforward space-saving companion. It can grow between young kale plants and be harvested before kale fills the bed.
- Use leaf lettuce or compact varieties.
- Leave open soil around the kale stem.
- Harvest lettuce as kale leaves begin overlapping it.
- Do not let a dense lettuce planting prevent water from reaching kale roots.
This combination works because of timing and plant size, not because lettuce chemically benefits kale.
Beets
Beets are another cool-season crop that can fit near kale. They have a lower canopy and can be harvested before a long-lived kale planting reaches full size.
Do not rely on the idea that root crops and leafy crops “use completely different soil layers.” Their roots still overlap, and both depend on the same moisture and nutrient supply. Give each crop enough room.
Sweet Alyssum and Flowering Borders
Sweet alyssum stays low and produces many small flowers, making it a useful border around a kale bed. It can provide food for beneficial insects without taking much canopy space from the crop.
Other flowering options include cilantro, dill, buckwheat, and selected native flowers nearby. Larger flowering plants are usually easier to manage outside the main vegetable row.
What About Rosemary, Sage, and Oregano?
These herbs are frequently listed as ideal kale companions because their aromas may affect insect behavior. The bigger practical issue is that mature Mediterranean herbs prefer drier soil than actively growing kale.
If you already grow rosemary, sage, oregano, or thyme, use them at the drier perimeter of the vegetable bed rather than interplanting them tightly with kale. Their flowers can also provide resources for beneficial insects.
Should Kale Be Planted With Broccoli, Cabbage, or Cauliflower?
Yes, they can physically grow together. Kale is not toxic to broccoli, cabbage, cauliflower, Brussels sprouts, or other brassicas.
The concern is that related crops share many of the same pests and diseases. University of Minnesota lists flea beetles, imported cabbageworm, cabbage looper, diamondback moth, cabbage maggot, black rot, Alternaria, and clubroot among problems that can affect kale or related brassicas.
A large uninterrupted brassica block therefore gives those pests and diseases many suitable hosts in one place. You do not need to separate individual brassicas by an arbitrary number of feet, but avoid needless crowding and rotate the entire plant family together.
For a related crop-specific layout, see Best Companion Plants for Broccoli.
Plants That Usually Fit Poorly Beside Kale
| Plant or situation | Why it can be a poor fit |
|---|---|
| Pumpkins and large squash | Vines can bury the base of kale and make harvest difficult |
| Tall corn on the sunny side | Can create too much shade |
| Tomatoes packed tightly with spring kale | Large plants compete heavily and prefer warmer seasonal conditions |
| Dense broccoli, cabbage, and cauliflower blocks | Concentrate shared brassica pests and diseases |
| Aggressive mint planted directly in the bed | Spreads into the root zone and becomes difficult to remove |
| Large established rosemary in the wettest part of the bed | Prefers drier conditions than kale |
A Practical 4-by-8-Foot Kale Bed
For full-size kale plants, keep the bed simple enough that you can reach every plant for repeated harvest.
- Plant kale in two staggered rows using the spacing recommended for your variety and harvest style.
- Add lettuce or beets in temporary gaps while the kale is young.
- Use onions or leeks along one side of the bed.
- Place thyme, cilantro, dill, or sweet alyssum along the perimeter.
- Harvest temporary companions as kale leaves expand.
- Keep one edge accessible for picking leaves and inspecting the undersides.
Companion Planting Will Not Replace Kale Pest Control
Kale is especially vulnerable to flea beetles when young and to imported cabbageworm, cabbage looper, and diamondback moth caterpillars throughout the season. Aphids and other pests can also become problems.
- Inspect leaves regularly, especially the undersides.
- Use row cover or insect netting early where practical.
- Hand-pick caterpillars in small gardens.
- Use an appropriate labeled biological control such as Bacillus thuringiensis var. kurstaki when needed.
- Remove heavily diseased or infested debris after harvest.
Flowers and aromatic companions may help reduce pest pressure or support natural enemies, but they should not be your only defense.
Crop Rotation Matters More Than Companion Charts
Kale belongs to the cabbage family along with broccoli, cauliflower, cabbage, Brussels sprouts, collards, mustard greens, radishes, turnips, and several other crops.
University of Minnesota recommends rotating plant families when managing garden diseases, generally keeping members of the same family out of the same location for two to four years where space allows.
Planting kale where broccoli grew last year is therefore not a true crop rotation. Move the whole brassica family together when planning future beds.
Common Kale Companion-Planting Mistakes
- Using invented percentages: There is no universal rule that a kale bed should be 70% kale and 30% companions.
- Promising a fixed pest reduction: Companion effects vary with pest species, climate, density, and timing.
- Assuming different roots do not compete: All plants still share soil water and nutrients.
- Grouping all brassicas together: This can make shared pest and disease problems easier to spread.
- Giving Mediterranean herbs too much water: Keep them toward drier bed edges.
- Ignoring mature kale size: A small transplant can become a broad, long-lived plant.
Frequently Asked Questions
What is the best companion plant for kale?
There is no single best companion. Onions are an easy structural fit, thyme has some research support in related brassica systems, and dill, cilantro, or sweet alyssum can support beneficial insects.
Can kale and onions grow together?
Yes. Their growth habits fit together well as long as each receives adequate spacing and water.
Can kale and lettuce grow together?
Yes. Lettuce can use open space around young kale and is often harvested before mature kale fills the bed.
Can kale be planted beside broccoli?
Yes, but both are brassicas and share many pests and diseases. Avoid unnecessary crowding and rotate the whole cabbage family together in future seasons.
Do herbs keep cabbage worms off kale?
Some aromatic plants can reduce pest pressure in specific systems, but they do not provide dependable complete protection. Row cover, scouting, hand-picking, and targeted controls are more reliable when caterpillars are active.
The Best Approach
Give kale its proper spacing and cool-season growing conditions first. Then use onions or leeks along the side, fast crops such as lettuce in temporary gaps, and flowering herbs or alyssum around the edge.
That simple layout provides more practical value than trying to follow a long list of “perfect companions” and “plants to never grow together.”
For the broader strategy behind these combinations, see our Companion Planting Guide, or continue exploring the Vegetables, Herbs & Edible Gardening hub.
