Kohlrabi Companion Plants

If you’re growing kohlrabi in your garden, you’ll want to know about kohlrabi companion plants. Choosing the right neighbors can make a big difference in your harvest. This guide will walk you through the best and worst plants to grow alongside this unique vegetable. You’ll learn how to boost growth, deter pests, and make the most of your garden space.

Companion planting is a simple and effective gardening method. It involves placing certain plants close together so they can help each other. This help can come in many forms. Some plants repel harmful insects, while others attract beneficial ones. Some improve soil nutrients, and others provide needed shade or support.

For kohlrabi, a cool-season crop from the brassica family, smart pairings are especially useful. They can help prevent common issues like cabbage worms and clubroot. Let’s look at the plants that make excellent companions for your kohlrabi.

Best Companion Plants for Kohlrabi

These plants offer clear benefits when grown near kohlrabi. They are your top choices for a healthy and productive bed.

1. Aromatic Herbs

Strong-smelling herbs are fantastic at confusing and repelling pests. Their scents mask the smell of kohlrabi from insects looking for a meal.

Dill, Mint, and Sage: These herbs deter cabbage moths, which lay eggs that become destructive worms.
Rosemary and Thyme: Their pungent aroma helps keep a variety of bugs at bay.
Chamomile: Known as a “plant doctor,” it can improve the health and flavor of kohlrabi.

Just be careful with mint, as it can be invasive. It’s often best grown in a container near your kohlrabi, rather then directly in the bed.

2. Alliums (Onion Family)

Plants like onions, garlic, leeks, and chives are powerhouse companions. Their strong smell is a major turn-off for many pests.

They repel aphids, cabbage loopers, and even rodents.
Chives and garlic have shown some ability to hinder fungal diseases.
They take up little space, making them easy to tuck between kohlrabi plants.

3. Nasturtiums and Marigolds

These are two of the most popular companion flowers for a reason.

Nasturtiums: They act as a “trap crop,” attracting aphids and cabbage worms away from your kohlrabi. Their bright flowers also attract pollinators.
Marigolds (French & Tagetes): Their roots release a substance that suppresses nematodes in the soil. These microscopic pests can damage kohlrabi roots.

4. Leafy Greens and Other Vegetables

Many common garden vegetables get along very well with kohlrabi.

Beets and Lettuce: These are shallow-rooted. They won’t compete with kohlrabi for nutrients and help utilize space efficiently.
Swiss Chard and Spinach: They have similar water and light needs, making them easy to manage together.
Celery: Some gardeners find it helps repel the white cabbage butterfly.
Cucumbers and Bush Beans: Beans fix nitrogen in the soil, which kohlrabi can use. Cucumbers can be grown nearby if they have ample space.

Plants to Avoid Near Kohlrabi

Just as some plants help, others can hinder. Avoid planting kohlrabi next to these.

1. Other Brassicas

This is the most important rule. Do not plant kohlrabi with its close cousins.

Avoid: Broccoli, Cauliflower, Kale, Brussels Sprouts, Cabbage, and Collards.
Reason: They all attract the same pests and diseases. Grouping them together makes it easy for problems to spread rapidly. They also compete for the same exact soil nutrients.

2. Nightshades

Tomatoes, peppers, and eggplants are generally poor companions.

They have different growing requirements, needing more heat.
Tomatoes in particular are heavy feeders and can out-compete kohlrabi for nutrients.

3. Pole Beans and Strawberries

These two have specific conflicts with kohlrabi.

Pole Beans: They are said to inhibit the growth of plants in the brassica family, including kohlrabi. Stick with bush beans instead.
Strawberries: They can attract slugs, which will also happily munch on kohlrabi leaves and stems.

Planning Your Kohlrabi Garden Layout

Knowing what to plant is half the battle. Now, let’s put it into practice with some layout ideas.

Interplanting for Space Efficiency

Kohlrabi grows relatively quickly. You can plant fast-growing crops between them.

Plant your kohlrabi seedlings at their recommended spacing (usually 6-8 inches apart).
Between each kohlrabi, sow seeds for lettuce, spinach, or radishes.
These quick crops will be harvested long before the kohlrabi needs the extra space.

Border Planting for Protection

Use the edges of your bed to create a protective barrier.

Plant a row of marigolds around the entire perimeter of your kohlrabi patch.
Add clumps of chives or onions at the corners.
This creates a first line of defense against invading pests.

Succession Planting with Companions

Time your plantings for a continous harvest.

After harvesting an early spring crop of kohlrabi with its companions, replant the space.
You can follow with a summer crop of bush beans, which will add nitrogen back to the soil.
Then, plant another round of kohlrabi with leafy greens in the late summer for a fall harvest.

Common Kohlrabi Problems and Companion Solutions

Companion planting is a key part of natural pest and disease management.

Preventing Cabbage Worms and Moths

This is the most common issue. The white cabbage butterfly lays eggs on leaves.

Solution: Interplant with plenty of aromatic herbs like dill, sage, and rosemary. Use nasturtiums as a sacrificial trap crop on the outskirts of the garden.

Deterring Aphids

These small sap-sucking insects can cluster on stems and undersides of leaves.

Solution: Plant alliums like garlic and chives nearby. The strong scent repels them. Also, attract beneficial insects like ladybugs by planting dill and marigolds.

Improving Soil Health

Healthy soil grows healthy plants that resist problems better.

Solution: Plant bush beans nearby to naturally add nitrogen. After harvest, chop the bean plants and leave them as green mulch to decompose.

Frequently Asked Questions

Can I plant kohlrabi next to tomatoes?

It is not recommended. Tomatoes and kohlrabi have different growing needs and compete for nutrients. They are generally considered incompatible companions.

What is a good companion for kohlrabi to repel bugs?

Onions, garlic, and herbs like mint and sage are excellent for repelling common kohlrabi pests such as cabbage worms and aphids.

How far apart should companion plants be from kohlrabi?

They can be quite close. For herbs and onions, you can plant them within 6-12 inches of your kohlrabi. For larger plants like cucumbers, give them there own space at least 12-18 inches away.

Can I grow carrots with kohlrabi?

Yes, carrots are a neutral companion. They have deep roots that don’t interfere with kohlrabi’s more shallow root system, so they make good use of space without competing.

What should you not plant near kohlrabi?

Avoid other brassicas (like broccoli and cabbage), pole beans, tomatoes, peppers, and strawberries for the best results.

Using companion planting for your kohlrabi is a smart, natural way to garden. It reduces the need for chemical interventions and creates a more resilient ecosystem in your backyard. By choosing friends like herbs, onions, and marigolds, and avoiding competitors like other brassicas, you set your kohlrabi up for success. Start with a few pairings this season and observe the benefits. You’ll likely find healthier plants, fewer pests, and a more bountiful harvest from your garden efforts.