Can You Plant Kale and Cabbage Together? - Plant Care Guide

Yes, you can absolutely plant kale and cabbage together, as they are both members of the Brassica oleracea species and share very similar growing requirements. In fact, interplanting them can be a beneficial strategy in a practice known as companion planting, helping to optimize space, suppress weeds, and potentially deter pests. However, because they are closely related, they also share vulnerabilities to the same pests and diseases, requiring careful management.

Are Kale and Cabbage Related?

Yes, kale and cabbage are very closely related, so much so that they are actually different cultivars (cultivated varieties) of the same plant species: Brassica oleracea. This botanical relationship is fundamental to understanding why they can be successfully planted together and why they share similar care needs and vulnerabilities.

Here's a breakdown of their relationship:

• Same Species: Both kale and cabbage originate from a wild mustard plant found in coastal western and southern Europe. Through centuries of selective breeding by humans, different traits were emphasized, leading to the diverse forms we see today.
• Different Cultivars:
  • Kale was bred for its large, edible, typically curly or crinkled leaves that do not form a compact head.
  • Cabbage was bred for its densely packed, overlapping leaves that form a tight, round or conical head.
• Broccoli, Brussels Sprouts, Collard Greens, Kohlrabi, and Gai Lan (Chinese Broccoli): These are also all cultivars of Brassica oleracea. They are all "siblings" from the same botanical family.
• Family: They belong to the Brassicaceae family, commonly known as the mustard family or cabbage family. This family also includes many other popular vegetables like broccoli, cauliflower, Brussels sprouts, collard greens, kohlrabi, turnips, and radishes.

Implications of their close relationship for gardening:

• Similar Growing Needs: Because they are genetically so close, kale and cabbage have almost identical requirements for sunlight, soil type, watering, and fertilization. This makes them good companions in the garden.
• Shared Pests and Diseases: This is the main drawback of planting them together. Since they are the same species, they are susceptible to the exact same pests (e.g., cabbage worms, aphids, flea beetles) and diseases (e.g., clubroot, black rot). This means if one plant gets an issue, the other is highly likely to get it too.
• Crop Rotation: Due to their shared vulnerabilities, it's crucial to practice crop rotation by not planting any Brassica oleracea (or any Brassica family member) in the same spot year after year. This helps break pest and disease cycles.

Understanding that kale and cabbage are just different forms of the same plant highlights why they are such compatible growing partners while also emphasizing the need for a unified pest and disease management strategy.

What Are the Shared Growing Requirements for Kale and Cabbage?

Because kale and cabbage are so closely related, they share almost identical growing requirements. This botanical compatibility is precisely what makes planting kale and cabbage together a natural and often beneficial choice for gardeners.

Here are the shared growing requirements for kale and cabbage:

1. Sunlight:
   • Full Sun: Both plants thrive in full sun, meaning at least 6-8 hours of direct sunlight per day. Adequate sunlight is crucial for strong growth and good head/leaf development.
   • Partial Shade: In very hot climates, they can tolerate some partial afternoon shade to prevent bolting (going to seed prematurely) or stress, but they will still need at least 4-6 hours of direct sun.
2. Soil:
   • Rich, Well-Draining Soil: Both prefer fertile, well-draining soil that is rich in organic matter.
   • pH: They grow best in a soil pH between 6.0 and 7.0, which is slightly acidic to neutral. A soil test kit can help you determine your soil's pH.
   • Amendments: Incorporate plenty of compost or well-rotted manure before planting to improve soil structure and fertility.
3. Watering:
   • Consistent Moisture: Both kale and cabbage need consistent, even moisture. They do not like to dry out completely, as this can lead to stress, bolting, or bitter-tasting leaves.
   • Deep watering: Water deeply at the base of the plants, avoiding overhead watering which can encourage fungal diseases. Aim for about 1-1.5 inches of water per week, either from rain or irrigation.
   • Mulch: Applying a layer of organic mulch around the plants helps retain soil moisture, suppress weeds, and regulate soil temperature.
4. Temperature:
   • Cool-Season Crops: They are both cool-season vegetables and prefer cooler temperatures.
   • Ideal Range: They thrive in temperatures between 55-75°F (13-24°C).
   • Frost Tolerance: Both can tolerate light frosts, which can actually improve their flavor (making them sweeter).
   • Heat Stress: High temperatures (above 80°F or 27°C) can cause them to bolt, become bitter, or stop growing vigorously.
5. Nutrients:
   • Heavy Feeders: Both kale and cabbage are considered heavy feeders, meaning they require a significant amount of nutrients, especially nitrogen, for lush leafy growth.
   • Fertilization: Amend soil with compost prior to planting. During the growing season, a balanced fertilizer or one slightly higher in nitrogen can be beneficial, especially after about a month of growth.
6. Air Circulation:
   • Good air circulation is important to help prevent fungal diseases. Space plants adequately.

By providing these shared ideal conditions, you'll ensure that both your kale and cabbage plants thrive when grown together, leading to a productive harvest.

What Are the Benefits of Planting Kale and Cabbage Together?

Planting kale and cabbage together can offer several advantages, especially when considering principles of companion planting and maximizing garden efficiency. Their shared needs and growth habits often make them cooperative neighbors in the vegetable patch.

Here are the key benefits of interplanting kale and cabbage:

1. Space Optimization (Intercropping):
   • Efficient use of space: Cabbage forms a dense, compact head, while kale tends to grow more upright with open leaves. This allows you to plant them in close proximity, utilizing garden space more efficiently. You can plant kale slightly in between cabbage plants.
   • No competition for light: Their different growth forms mean they generally don't shade each other out excessively.
2. Shared Growing Requirements (Ease of Care):
   • As members of the same species, they have identical needs for sun, soil, water, and nutrients. This simplifies care, as you don't need to tailor specific conditions for each plant. What's good for kale is good for cabbage.
3. Weed Suppression:
   • When planted at appropriate densities, the combined foliage of kale and cabbage creates a canopy that shades the soil surface. This can help suppress weed growth by blocking sunlight, reducing competition for resources, and keeping the garden bed tidier.
4. Potential Pest Distraction/Trap Cropping (Limited):
   • While both are susceptible to the same pests, having more of the same family members in one area can sometimes offer a slight "dilution effect", meaning pests might spread out rather than concentrating on a single plant.
   • In some companion planting theories, one brassica might act as a "trap crop" for another, drawing pests away, though this is not a strong effect between kale and cabbage themselves. It's more effective when interplanted with non-brassica companions.
5. Aesthetic Appeal:
   • The different leaf textures and growth habits (curly kale next to smooth cabbage heads) can create an interesting and attractive visual contrast in the garden bed. Ornamental cabbage and kale are even used specifically for this purpose.
6. No Negative Interactions:
   • Crucially, there are no known negative allelopathic effects or competitive disadvantages when planting kale and cabbage directly together, unlike some less compatible plant pairings.

While their shared pest susceptibility is a point to manage, the combined benefits of space efficiency, simplified care, and natural weed suppression make planting kale and cabbage together a practical and often rewarding strategy for many gardeners.

What Are the Risks of Planting Kale and Cabbage Together?

While planting kale and cabbage together offers some benefits, their close botanical relationship also means they share the same vulnerabilities. Understanding these risks is crucial for effective garden management and preventing widespread issues.

Here are the key risks associated with interplanting kale and cabbage:

1. Shared Pest Susceptibility (Major Risk):
   • Same Pests, Double the Trouble: Since they are the same species (Brassica oleracea), kale and cabbage are attractive to and susceptible to the exact same insect pests. If pests like cabbage worms (cabbage loopers, imported cabbage worms, diamondback moths), aphids, or flea beetles find one plant, they will very quickly spread to the other.
   • Rapid Infestation: A localized outbreak can rapidly become a widespread infestation affecting both crops, potentially devastating your harvest of both kale and cabbage.
   • Pest Hotspots: Planting large blocks of brassicas together can create a "pest hotspot" that attracts and sustains higher populations of these specific pests.
2. Shared Disease Susceptibility (Major Risk):
   • Common Diseases: Just like pests, kale and cabbage are vulnerable to the same diseases, such as clubroot, black rot, downy mildew, and powdery mildew.
   • Quick Spread: If a fungal or bacterial disease appears on one plant, it can easily and quickly spread to the neighboring, genetically similar plant, leading to significant crop loss for both.
3. Nutrient Competition (If Soil is Poor):
   • Both are heavy feeders, requiring a good amount of nitrogen and other nutrients for lush growth. If your soil isn't sufficiently rich or adequately fertilized, kale and cabbage planted closely together can compete for available nutrients, potentially stunting the growth of both plants.
4. Space Competition (If Planted Too Closely):
   • While their growth habits are somewhat complementary, if planted too densely, the plants can still compete for sunlight, air circulation, and root space. Overcrowding can lead to smaller harvests and increase the risk of fungal diseases due to poor airflow.
5. Crop Rotation Challenges:
   • Because they are the same species, planting them together effectively means you've used that garden bed for a single Brassica crop. This makes crop rotation even more critical. You cannot simply plant cabbage in the same spot the next year just because it was a different "type" of plant from kale. The entire area should be avoided for any Brassica for 3-4 years to break pest and disease cycles.

To successfully plant kale and cabbage together, these shared risks must be actively managed through vigilant pest and disease monitoring, proper spacing, adequate fertilization, and strict crop rotation in subsequent seasons.

What Are Good Companion Plants for Kale and Cabbage?

While kale and cabbage are natural companions for each other, interplanting them with other, non-Brassica species can significantly boost their health, deter shared pests, and improve overall garden productivity. This strategy, known as companion planting, leverages the diverse characteristics of different plants.

Here are some good companion plants for kale and cabbage, along with their benefits:

1. Aromatic Herbs (Pest Deterrents):
   • Mint (in containers!): The strong scent can confuse and repel cabbage worms, aphids, and flea beetles. Plant in containers near brassicas to prevent mint from taking over.
   • Rosemary: Similar to mint, its strong aroma can deter various pests.
   • Thyme: Good ground cover, can deter cabbage moths.
   • Sage: Repels cabbage moths and flea beetles.
   • Dill: Attracts beneficial insects like parasitic wasps and ladybugs, which prey on aphids and cabbage worms. It can also deter cabbage moths.
   • Chamomile: Believed to improve the growth and flavor of nearby plants.
2. Onion Family Plants (Pest Repellents):
   • Onions, Garlic, Chives, Leeks: The strong sulfurous scent of alliums is known to deter many common brassica pests, including aphids, slugs, and cabbage worms.
3. Marigolds (Pest Repellents & Attractors):
   • French Marigolds (Tagetes patula): Release compounds from their roots that deter nematodes. Their strong scent can also confuse other pests.
   • African Marigolds (Tagetes erecta): Can act as a trap crop for spider mites, drawing them away from your brassicas.
4. Nasturtiums (Trap Crop & Visual Deterrent):
   • Trap Crop: Aphids absolutely love nasturtiums. Planting them nearby can draw aphids away from your kale and cabbage. Once heavily infested, you can remove and destroy the nasturtiums (and the aphids).
   • Visual Deterrent: Their bright flowers might confuse cabbage moths.
5. Lettuce & Spinach (Ground Cover & Weed Suppression):
   • Benefits: These low-growing greens act as a living mulch, shading the soil, retaining moisture, and suppressing weeds. They also have different nutrient needs and pest vulnerabilities.
6. Celery & Potatoes:
   • Can be beneficial neighbors, potentially improving growth or deterring certain pests.
7. Beans (Nitrogen Fixers - avoid directly near, good in rotation):
   • While not directly interplanted in the same small space, beans are legumes that fix nitrogen in the soil. They are excellent in a crop rotation before brassicas, providing a nitrogen boost. Avoid planting them too close if the brassicas are large, as they can compete.
8. Beneficial Insect Attractors:
   • Sweet Alyssum, Borage, Yarrow: These plants produce small flowers that attract a wide range of beneficial insects like hoverflies (larvae eat aphids), parasitic wasps, and ladybugs. Planting them nearby creates a "pest police" force.

What to Avoid (Bad Companions):

• Strawberries: Can hinder growth of brassicas.
• Tomatoes, Peppers, Eggplant: Can inhibit growth.
• Grape Vines: Also inhibit growth.

By strategically incorporating a variety of these companion plants around your kale and cabbage, you can create a more resilient, diverse, and pest-resistant garden ecosystem, leading to healthier and more abundant harvests.

How to Manage Pests When Planting Kale and Cabbage Together

Given that kale and cabbage share the same pest vulnerabilities, effective pest management is absolutely critical when planting them together. A proactive, integrated approach will be necessary to protect both crops from common nuisances like cabbage worms and aphids.

Here’s how to manage pests when planting kale and cabbage together:

1. Physical Barriers (Row Covers):
   • Most effective preventative: This is the best defense against flying pests like cabbage moths (which lay the eggs for cabbage worms) and flea beetles. Immediately after planting, cover your kale and cabbage beds with lightweight floating row covers.
   • Seal edges: Ensure the edges are firmly secured to the ground (with soil, rocks, or pins) to prevent pests from crawling underneath.
   • Remove for pollination (if needed): Remember to temporarily remove covers if your brassicas are flowering and need insect pollination (though kale and cabbage are mostly grown for leaves/heads before flowering).
2. Vigilant Monitoring:
   • Daily checks: Inspect your plants daily, especially the undersides of leaves, for signs of pests. Look for eggs, small larvae, aphids, or flea beetle damage (small holes). Early detection is key.
   • Sticky traps: Use yellow sticky traps to monitor flying pests.
3. Manual Removal:
   • Hand-picking: For cabbage worms, hand-picking them off the leaves and dropping them into a bucket of soapy water is very effective, especially for small infestations. Do this in the early morning.
   • Water blast: For aphids, a strong blast of water from a hose can dislodge them. Repeat every few days.
4. Organic Pest Control Sprays:
   • Bt (Bacillus thuringiensis): This is a naturally occurring bacterium that is very effective against cabbage worms (caterpillars). It's safe for humans, pets, and beneficial insects. Apply as soon as you see small caterpillars. Organic Bt spray is widely available.
   • Neem Oil: An organic pesticide that acts as an antifeedant, growth disruptor, and repellent. Effective against aphids, whiteflies, and young caterpillars. Apply thoroughly, covering all leaf surfaces.
   • Insecticidal Soap: Effective against soft-bodied pests like aphids and spider mites. Works by suffocating them. Direct contact is necessary.
5. Encourage Beneficial Insects:
   • Plant companion flowers and herbs like dill, fennel, calendula, sweet alyssum, and borage to attract predatory insects like ladybugs, lacewings, and parasitic wasps, which prey on aphids and cabbage worms.
6. Crop Rotation (Long-Term Strategy):
   • Because they share the same vulnerabilities, strict crop rotation is essential over multiple seasons. After harvesting your kale and cabbage, do not plant any other Brassica family member (broccoli, cauliflower, mustard greens, radishes, etc.) in that exact spot for at least 3-4 years. This breaks the life cycles of pests and diseases that might overwinter in the soil.
7. Cleanliness:
   • Remove and destroy any heavily infested or diseased leaves/plants immediately. Do not compost diseased material.
   • Clean up all plant debris at the end of the season to remove overwintering sites for pests.

By combining physical barriers with vigilant monitoring and targeted organic treatments, you can successfully manage pests when planting kale and cabbage together, ensuring a healthy and productive harvest from both crops.

How to Manage Diseases When Planting Kale and Cabbage Together

Just as with pests, kale and cabbage share susceptibility to the same diseases because of their close botanical relationship. When planting them together, a proactive and preventative approach to disease management is essential to avoid widespread crop loss.

Here’s how to manage diseases when planting kale and cabbage together:

1. Start with Healthy, Certified Disease-Free Plants/Seeds:
   • Purchase seeds or seedlings from reputable sources that guarantee disease-free stock. This is your first line of defense.
   • Consider disease-resistant varieties if available in your area.
2. Practice Strict Crop Rotation (Most Important Strategy):
   • Avoid planting brassicas in the same spot: This is paramount. Do not plant kale, cabbage, or any other member of the Brassica family (broccoli, cauliflower, Brussels sprouts, radishes, mustard greens, etc.) in the exact same garden bed for at least 3-4 years.
   • Why it works: Many soil-borne diseases (like clubroot, black rot, Fusarium wilt) can remain in the soil for years. Rotating crops to different families breaks the disease cycle by removing the host plant.
3. Ensure Good Drainage:
   • Prevent root diseases: Many fungal diseases (like damping-off or root rot) thrive in wet, poorly drained soil. Amend your soil with compost to improve drainage and aeration. Plant in raised beds if your native soil is heavy clay.
   • Use well-draining soil: Ensure your planting medium is never waterlogged.
4. Provide Adequate Spacing and Air Circulation:
   • Prevent fungal issues: Plant kale and cabbage with enough space between them to allow for good airflow around the foliage. Overcrowding creates humid, stagnant conditions that are ideal for the development and spread of fungal diseases like downy mildew and powdery mildew.
5. Water Properly:
   • Water at the base: Water deeply at the base of the plants. Avoid overhead watering (especially in the evening), which keeps foliage wet for extended periods and encourages fungal diseases.
6. Maintain Garden Hygiene (Sanitation):
   • Remove diseased plants/leaves: As soon as you spot any signs of disease (e.g., spots, wilting, discoloration), immediately remove and destroy the affected plant or leaves. Do NOT compost diseased material, as this can spread pathogens throughout your garden. Bag it and send it to a landfill.
   • Clean tools: Sterilize your gardening tools (pruners, trowels) with rubbing alcohol or a bleach solution after working with diseased plants to prevent cross-contamination.
   • Clear debris: Remove all plant debris at the end of the season. Don't leave old brassica leaves in the garden, as they can harbor disease spores and overwintering pests.
7. Soil Solarization (for severe issues):
   • If you have persistent, severe soil-borne diseases in a specific bed, soil solarization (covering moist soil with clear plastic in hot summer sun for 4-6 weeks) can help kill pathogens.

By proactively implementing these disease management strategies, you can significantly reduce the risk of diseases when planting kale and cabbage together, ensuring a healthier and more productive harvest from both crops.