As one of the most popular and most pest prone garden vegetables, kale has a lot to gain from companion planting. Proper planting and care will go a long way toward making kale more resilient, but companion planting can actively deter pests, improve the soil, and even lure pests away from kale.
This guide breaks down what types of plants grow well with kale, what to avoid planting with it to minimize the likelihood of pest infestations, and how to incorporate kale into a healthy crop rotation.
Skip Ahead: Companion planting benefits • Best kale companion plants • What not to plant with kale • Common kale pests • Companion planting chart
Benefits of companion planting for kale
As a brassica, kale is particularly susceptible to damage from caterpillars, aphids, and other common kale pests. While kale can help a few of its companions, it'll be on the receiving end of most of these benefits.
When you're choosing what to plant with kale, it can be helpful to start with exactly what you want your planting to help with. Here are a few ways that companion plants can benefit kale:
- Covering soil: Some companions sprawl to cover the soil between plants, suppressing weeds and improving water retention while kale becomes established.
- Maximizing space: You can maximize space in a small garden by companion planting kale with root crops that won't compete with kale for nutrients.
- Deterring pests: Nearly every kale companion can help with pest problems, either by masking kale's scent or by actively repelling pests.
- Attracting beneficial insects: Growing plants that attract beneficial predatory insects and parasitic insects is one of the best methods of pest control that organic gardeners have. For kale, this includes companion flowers and aromatic herbs.
The best kale companion plants
Kale plants need ample space-- at least a square foot each-- and they're highly susceptible to damage from pests like caterpillars and worms. When you're choosing what to plant next to your kale, consider what you'd like that plant to do: repel cabbage worms, lure pests away from the kale, suppress weeds and cover the soil, or maximize your garden space.
Some companions offer more than one of these benefits: garlic and onions, for example, will maximize space and deter pests. You can also combine companions for greater effect, like planting kale with marigolds to repel pests and planting a more attractive trap crop like radishes nearby. (For a quick overview, skip ahead to the companion planting chart at the end of this post.)
Companion planting can get very specific, drilling down into which plants to intercrop for specific species of parasitic insects or pests. This level of detail can be helpful for people growing at scale, but for most gardeners it's enough to focus on increasing biodiversity overall in a way that makes sense for the space that you have. As a general rule, an interplanted garden will be healthier than a monoculture.
With that in mind, here are the vegetables, herbs, and flowers to try planting with kale for a more productive crop:
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1. Alliums
Companion planting with onions, garlic, or chives can help reduce damage from a host of common kale pests, including diamondback moths, cabbage loopers, and aphids. Alliums can mask the scent of nearby plants, making it more difficult for some pests to find their host plants. Other pests may be actively deterred by the scent.
Growing onions or garlic with your kale is also space efficient; the alliums take up little space above the ground and won't compete with the kale too much for root space or nutrients. They can also be treated as cover crops; when you harvest the onions or garlic, leaving the tops on the soil as a mulch can help improve soil nutrition.
Read More: The 12 Best Companion Plants for Chives
2. Radishes
Radishes are a quick maturing, easy-to-grow vegetable that will germinate and be ready to harvest well before kale plants mature. While kale gets established, radishes will fill the soil, maximize your space, and provide a little catch crop in the meantime.
Radishes are also an excellent trap crop for flea beetles. If you struggle with these little black beetles chewing through your brassicas, a sacrificial sowing of radishes may help.
The only downside to companion planting with radishes is that as a brassica, they are also susceptible to damage from kale pests like cabbage loopers. To prevent this, cover the plants with a floating row cover when planting the bed and check for caterpillars regularly.
Finally, give radishes consistent watering. Without it, they're prone to developing woody stems and splitting at the root.
3. Lettuces
While lettuces won't repel pests, they will maximize space and they're fast growing. Interplanted with radishes, garlic, onions, or chives, growing lettuces is a great way to fill the wide gaps between kale plants.
For a steady supply of lettuces, succession sow a few plants every couple of weeks. Alternatively, you can extend your harvest by removing the outer leaves of a few plants when they're ready, instead of cutting the whole plant down to the crown.
4. Oregano
Companion planting with oregano can help reduce damage from whiteflies, and it may also confuse aphids and other common pests. If allowed to flower, oregano will support parasitic wasps and tachinid flies, which parasitize cabbage loopers, beetles, aphids, and other true bugs.
Oregano spreads very easily and enjoys the same moderately rich soil as kale. If you plant them in a raised bed or in the ground together, expect to harvest the oregano regularly to keep it in check.
Read More: The 14 Best Herbs to Grow at Home
5. Sage
Planting kale with sage can help repel pests like flea beetles, cabbage loopers, aphids, and diamondback moths. When combined with a trap crop like radishes, sage can be part of an effective 'push-pull' approach to keeping beetles and cabbage loopers away from your kale.
Kale and sage both enjoy loamy, well drained soil, though sage will have the best flavor when grown in poor soil.
6. Thyme
Thyme is one of the most widely studied companion plants, and there's research to show that it can be effective at dealing with a wide range of pests. In fact, thyme is one of the best companions for reducing pest damage in cruciferous vegetables overall.
Specifically, thyme can reduce diamondback moth infestations on brassicas and it may help to repel whitefly.
Like oregano, thyme spreads fairly aggressively and will enjoy full sun and moderately rich soil with good drainage. Flowering thyme will also support beneficial insect predators and parasitoids like hoverflies, lacewings, parasitic wasps, and tachinid flies.
Read More: The 8 Best Companion Plants for Thyme
7. Dill
Dill and other carrot family plants are fantastic for supporting predatory insects like hoverflies, lacewings, ladybugs, aphid midges, and parasitic wasps and flies. For brassicas, this can mean less damage from diamondback moths, cabbage loopers, cabbage worms, beetles, aphids, and mites.
Dill likes rich, well drained soil and regular watering. It's a tall plant and needs full sun, so it'll have its best chance of performing well when planted behind kale.
Read More: The 10 Best Companion Plants for Dill
8. Marigolds
Marigolds are one of the best companion flowers for vegetables of any variety, thanks to their ability to repel pests. Marigolds can help to protect against whiteflies, reduce damage from aphids, cabbage butterflies, cabbage moths, and flea beetles, reduce root-knot nematode populations, and support parasitic wasps.
Perhaps most importantly for kale, companion planting with marigolds can reduce diamondback moth populations and prevent cabbage root flies from finding brassica plants.
French and African marigolds are both fantastic companions for kale. They need full sun and, like kale and Mediterranean herbs, they want the soil to dry out a bit between waterings. Planted next to kale, marigolds won't need any special kale.
9. Nasturtiums
Nasturtiums are another popular companion flower, as they're easy to grow, edible, and can function as a living mulch.
When it comes to pests, nasturtiums are known to help reduce whitefly populations. They can also be grown as a trap crop for nematodes and aphids, which prefer nasturtiums to most other garden plants.
If you struggle with nematodes, try planting nasturtium a short distance from where your kale will go. To use nasturtiums to suppress weeds and cover the soil, plant them right up next to your brassicas.
What not to plant with kale
In a small garden, kale will get along well enough with most vegetables and herbs. But if you have enough space to be choosy, it's best to avoid planting kale with these herbs and vegetables:
1. Tomatoes
Tomatoes and kale do not generally grow well together. They tend to compete for root space, nutrients, and sun, leaving both plants slightly worse off. As fruiting vegetables, tomatoes also like more nutrition in the soil than brassicas do.
Instead of growing tomatoes with kale, a better option might be incorporating them into a crop rotation where kale follows tomatoes. That way, you can amend the soil heavily for tomatoes each year, let the tomatoes deplete some of that nutrition, harvest them, and plant kale directly into the soil without another amendment.
This kind of rotation is cost effective, but it also ensures that both plants have their soil needs met.
If you're gardening in a small space and want to keep both plants, consider separating them with one of their shared companions: marigolds, onions, or nasturtiums.
Read More: The 11 Best Companion Plants for Tomatoes
2. Cucurbits
Like tomatoes, cucurbits don't grow well with kale. Plants like cucumbers, melons, watermelons, and squash will compete with kale for nutrients, and they also need much richer soil.
Instead of growing cucurbits with kale, consider interplanting them with cucumber companion plants like peas, dill, marigolds, or nasturtiums.
3. Brassicas
Planting kale with other brassica family crops can lead to more damage from their shared pests. If you do want to plant kale with broccoli, cabbages, cauliflower, bok choy, or other brassicas, consider interplanting them with a pest-deterring companion plant like marigolds or onions.
Read More: The 10 Best Companion Plants for Broccoli
4. Mint
Mint is effective at confusing pests like cabbage root flies, but it spreads too aggressively to be planted in the soil. Instead of planting mint with kale in the ground or in a raised bed together, you could try planting mint in a pot and positioning it near the plants you want to protect from pests.
Read More: The 13 Best Companion Plants for Mint
5. Fennel
A close relative of dill, fennel is another boon to a pollinator garden or vegetable garden. Its umbel flowers support a wealth of beneficial insects, including predatory insects and parasitic ones.
Unfortunately, fennel is also allelopathic, meaning it releases a chemical into the soil that can inhibit the growth of neighboring plants. This can be a non-issue in well designed flower borders, but it's more of a concern for vegetables like kale.
Common kale pests
Like other brassicas, kale suffers from a long list of pests. Some of them, like diamondback moths and cabbage white butterflies, plague gardeners and farmers around the world. Companion planting can help to create a more resilient garden, but it won't eliminate pest issues.
Here are the most common kale pests to keep an eye out for:
- Cabbage aphids
- Cabbage loopers
- Cabbage worms
- Diamondback moth
- Cutworms
- Armyworms
- Flea beetles
- Thrips
- Whitefly
- Nematodes
Cabbage aphids, cabbage worms, and diamondback moths are among the most common and most damaging garden pests. All of them can be controlled to some extent by parasitic wasps and flies, but it's often necessary to take a more proactive role.
In the spring, you can protect young brassica plants from flea beetles, whitefly, aphids, worms, and moths by covering the plants with a lightweight floating row cover. If you're growing an entire bed or row of kale plants, it's worth taking a few minutes every day or every couple of days to pluck off caterpillars. It's a tedious job, but manually removing pests and using a row cover can mean extra months of harvests.