Kohlrabi Companion Plants

Kohlrabi grows well alongside leafy greens and herbs that share its growing conditions, and choosing the right kohlrabi companion plants can make a real difference in your garden. By pairing this crunchy, above-ground bulb with the right neighbors, you can naturally deter pests, improve soil health, and get a better harvest. Let’s look at what to plant next to kohlrabi, what to avoid, and how to set up your garden bed for success.

Kohlrabi is a cool-season crop, part of the cabbage family. It likes full sun, consistent moisture, and fertile soil. Because it grows fast, it doesn’t need to stay in the ground for a long time, but it still benefits from good companions that don’t compete too hard for nutrients.

Why Companion Planting Matters For Kohlrabi

Companion planting is not just about filling space. It’s about creating a mini-ecosystem where plants support each other. Some plants repel pests, others attract beneficial insects, and some simply help shade the soil or mark rows.

For kohlrabi, the main threats are cabbage worms, aphids, and flea beetles. The right neighbors can confuse these pests or bring in predators that eat them. Also, because kohlrabi is a brassica, it has similar needs to cabbage, broccoli, and kale, so many of the same companion rules apply.

You don’t need a huge garden to benefit. Even a small raised bed or a few containers can work well if you choose the right plant combinations.

Now, let’s get into the specifics. The best companions for kohlrabi fall into a few groups: aromatic herbs, leafy greens, root vegetables, and flowers. Each one brings something different to the table.

Best Herbs To Plant With Kohlrabi

Herbs are often the most valuable companions because their strong scents confuse pests. Here are the top herbs to consider:

Dill: Dill attracts beneficial wasps that prey on cabbage worms. It also improves the overall health of brassicas. Just let it flower, and it will do its job.
Chamomile: This herb adds calcium to the soil, which kohlrabi loves. It also has a mild scent that helps mask the kohlrabi from pests.
Mint: Mint repels ants and aphids, but be careful. Mint is invasive, so plant it in a pot sunk into the ground to keep it contained.
Rosemary: Rosemary has a strong aroma that deters cabbage moths and flea beetles. It prefers drier soil, so plant it on the edge of the bed.
Thyme: Thyme is a low-growing herb that can act as a living mulch, keeping the soil cool and moist around kohlrabi.
Sage: Sage repels cabbage moths and carrot flies. It’s a woody herb, so give it some space to spread.

When planting herbs, don’t overcrowd the kohlrabi. Herbs need airflow, and kohlrabi needs room to form its bulb. A good rule is to plant herbs on the outer edges or between rows, not directly in the same hole.

Leafy Greens That Work Well

Leafy greens are great because they have shallow roots and don’t compete with kohlrabi for deep nutrients. They also provide ground cover, which helps retain soil moisture.

Lettuce: Lettuce grows fast and can be harvested before kohlrabi needs more space. It also shades the soil, keeping it cool.
Spinach: Spinach is another fast grower. It tolerates cool weather and won’t bother the kohlrabi.
Arugula: Arugula has a peppery scent that can deter some pests. It also matures quickly, so you can harvest it early.
Swiss Chard: Chard has deeper roots than lettuce, but it still won’t compete too much. Its colorful stems add beauty to the garden.
Beet Greens: If you grow beets for the roots, the greens are also edible. They work well as a companion because they don’t spread too wide.

One thing to note: avoid planting kohlrabi near other brassicas like cabbage or broccoli. They compete for the same nutrients and attract the same pests. If you have a small garden, this can be a problem. Instead, rotate your brassicas to different spots each year.

Root Vegetables That Share Space Well

Root vegetables are good companions because they use different soil layers. While kohlrabi feeds from the upper soil, root crops go deeper. This reduces competition.

Beets: Beets are a classic companion. They don’t mind the cool weather and they help break up the soil slightly.
Carrots: Carrots grow deep and don’t compete with kohlrabi’s shallow roots. They also don’t attract the same pests.
Radishes: Radishes are excellent trap crops. They attract flea beetles away from kohlrabi. Plant a few radishes early, and the beetles will go for them instead.
Onions: Onions have a strong smell that repels many insects. They also take up little space and can be planted between kohlrabi plants.
Garlic: Garlic is similar to onions. It repels aphids and adds a layer of protection. Plant it around the perimeter of the bed.

When planting root vegetables, make sure the soil is loose and not compacted. Kohlrabi doesn’t like heavy soil, and neither do carrots. If your soil is clay-heavy, add compost before planting.

Flowers That Help Kohlrabi

Flowers are not just pretty. They attract pollinators and beneficial insects that keep pests in check. Here are some of the best flowers for kohlrabi:

Nasturtiums: Nasturtiums are a top choice. They act as a trap crop for aphids and also repel whiteflies. Their bright flowers add color and they are edible too.
Marigolds: Marigolds repel nematodes and other soil pests. Their strong scent confuses cabbage moths. Plant them around the edges of the bed.
Calendula: Calendula attracts hoverflies, which eat aphids. It also has medicinal properties and looks lovely in the garden.
Alyssum: Sweet alyssum is a low-growing flower that attracts tiny beneficial wasps. These wasps parasitize cabbage worms. It’s a great ground cover.
Borage: Borage is a tall flower that attracts bees and other pollinators. It also adds minerals to the soil when it decomposes.

Flowers are easy to tuck in between rows or at the corners of your bed. They don’t need much space, and they make the garden more inviting for beneficial insects.

Plants To Avoid Near Kohlrabi

Just as some plants help, others can hurt. Avoid these plants near kohlrabi:

Strawberries: Strawberries can harbor pests and diseases that affect brassicas. They also compete for space and nutrients.
Tomatoes: Tomatoes need more warmth and nutrients than kohlrabi. They also attract different pests, but they can shade the kohlrabi too much.
Pole Beans: Beans fix nitrogen in the soil, but pole beans can shade kohlrabi and compete for space. Bush beans are a bit better, but still not ideal.
Other Brassicas: Cabbage, broccoli, cauliflower, and kale should not be planted next to kohlrabi. They share the same pests and diseases, and they compete for the same nutrients.
Fennel: Fennel is allelopathic, meaning it releases chemicals that inhibit the growth of nearby plants. Keep it far away.

If you have limited space, focus on the herbs and flowers first. They give the most benefit without taking up too much room.

How To Plan Your Kohlrabi Garden Bed

Planning is key to a successful companion planting setup. Here’s a step-by-step guide to help you organize your bed:

Choose a sunny spot: Kohlrabi needs at least 6 hours of sun. Morning sun is best, with some afternoon shade in hot climates.
Prepare the soil: Kohlrabi prefers well-draining soil with a pH between 6.0 and 7.5. Mix in compost before planting to add nutrients.
Plant kohlrabi first: Space kohlrabi plants about 6-8 inches apart. They need room to form their bulbs.
Add companions around them: Plant herbs and flowers on the edges. Tuck in leafy greens between the kohlrabi plants, but don’t overcrowd.
Water consistently: Kohlrabi needs steady moisture. Inconsistent watering can make the bulbs woody. Use mulch to retain moisture.
Monitor for pests: Check your plants regularly. If you see cabbage worms, pick them off by hand. Use row covers if pests are severe.
Harvest at the right time: Kohlrabi is ready when the bulb is about 2-3 inches in diameter. Don’t let it get too large, or it becomes tough.

Following this plan will give you a healthy, productive bed. The companions will do their part, and you’ll have less work to do.

Companion Planting In Containers

If you don’t have a garden bed, you can still grow kohlrabi in containers. Use a pot that is at least 12 inches deep and wide. Plant one kohlrabi per pot, and add small companions like thyme or alyssum around the edges.

Containers dry out faster, so check the soil daily. You may need to water more often, especially in warm weather. Use a high-quality potting mix and add a slow-release fertilizer.

Container gardening is a great option for balconies or small patios. Just make sure the pot has drainage holes and gets enough sun.

Common Problems And Solutions

Even with good companions, you might run into issues. Here are some common problems and how to fix them:

Flea beetles: These tiny black bugs chew small holes in the leaves. Plant radishes as a trap crop, or use floating row covers.
Cabbage worms: Green caterpillars that blend in with the leaves. Check the undersides of leaves and remove them. Beneficial wasps from dill and alyssum will help.
Aphids: Small green or black insects that cluster on new growth. Spray them off with water, or introduce ladybugs. Nasturtiums will attract them away.
Bolting: If the weather gets too hot, kohlrabi may bolt and go to seed. Plant early in the season and provide shade if needed.
Woody bulbs: This happens when the plant gets too much heat or too little water. Keep the soil moist and harvest on time.

Most of these problems can be prevented with good companion planting and consistent care. If you notice an issue early, it’s easier to fix.

Seasonal Tips For Kohlrabi

Kohlrabi is a cool-season crop, so timing matters. Here are some seasonal tips:

Spring planting: Plant kohlrabi 4-6 weeks before the last frost. It can tolerate light frost, and the cool weather helps it grow sweet and tender.
Fall planting: For a fall crop, plant kohlrabi 6-8 weeks before the first frost. The cooler temperatures in autumn are ideal.
Summer care: If you live in a hot climate, kohlrabi may struggle in summer. Provide afternoon shade and keep the soil cool with mulch.
Succession planting: Plant a few kohlrabi seeds every 2-3 weeks to have a continuous harvest. This works well in spring and fall.

By timing your planting well, you can enjoy kohlrabi for a longer period. The companions will also thrive in the same cool conditions.

Frequently Asked Questions

Can I plant kohlrabi next to tomatoes?
No, it’s best to avoid tomatoes. They need different growing conditions and can shade the kohlrabi. Stick with cool-season companions.

What is the best companion for kohlrabi?
Nasturtiums and radishes are two of the best. Nasturtiums repel aphids, and radishes attract flea beetles away from the kohlrabi.

How much space does kohlrabi need?
Kohlrabi needs about 6-8 inches between plants. If you’re planting in rows, space the rows about 12 inches apart.

Can kohlrabi be planted with lettuce?
Yes, lettuce is a great companion. It grows fast, shades the soil, and doesn’t compete with kohlrabi for nutrients.

Does kohlrabi need full sun?
Kohlrabi prefers full sun but can tolerate partial shade, especially in warmer climates. Aim for at least 6 hours of sun daily.

How do I know when kohlrabi is ready to harvest?
Harvest when the bulb is 2-3 inches in diameter. It should feel firm and look slightly swollen at the base. Don’t wait too long, or it becomes woody.

Final Thoughts On Companion Planting

Companion planting is a simple way to make your garden healthier and more productive. By choosing the right kohlrabi companion plants, you can reduce pest problems and improve your harvest without using chemicals.

Start with a few easy companions like lettuce, radishes, and nasturtiums. As you get more comfortable, add herbs like dill and thyme. You’ll notice the difference in both plant health and your own gardening experience.

Remember to keep the soil moist, provide good airflow, and harvest at the right time. With a little planning, you can enjoy fresh, crunchy kohlrabi straight from your garden. And your companion plants will make the whole process easier and more rewarding.

If you’re new to this, don’t worry. You’ll learn as you go. The key is to observe your plants and adjust as needed. Gardening is a hands-on activity, and every season teaches you something new. So get out there, plant your kohlrabi with some good neighbors, and watch your garden thrive.