Basil is a favorite herb for many gardeners, known for its aromatic leaves and versatility in the kitchen. Whether used for making pesto, garnishing dishes, or adding flavor to meals, basil thrives in sunny spots and is easy to grow in containers or garden beds. However, while basil is a resilient plant, it has specific requirements that must be met to ensure its success. One of the most effective ways to promote healthy basil growth is through companion planting—strategically selecting nearby plants that support each other’s growth.
However, not all plants make good companions for basil. Some can stunt its growth, attract pests, or cause diseases. In this article, we’ll discuss the worst companion plants for basil and why you should avoid planting them together. We’ll also provide tips on how to create a healthy, thriving garden for your basil.
The Importance of Companion Planting
Companion planting is the practice of planting different species of plants in close proximity to each other to help with growth, pest control, and overall garden health. Plants that work well together tend to have similar environmental needs, help each other by attracting beneficial insects, or improve the soil condition for neighboring plants. On the other hand, some plants can negatively impact each other, causing stunted growth, pest problems, or disease transmission.
When it comes to basil, it’s essential to avoid plants that may hinder its growth or introduce harmful pests. Incompatible plants might compete for space, water, and nutrients, making it difficult for basil to thrive. By choosing the right companions, you can enhance basil’s health, flavor, and overall productivity.
Bad Companion Plants for Basil
Here are some of the worst plants to grow near basil and why they should be avoided:
1. Rue (Ruta graveolens)
Rue is a herb known for its distinctive smell and medicinal properties. While it’s often used in various herbal remedies, it does not make a good companion for basil.
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Why it's bad: Rue is allelopathic, meaning it produces natural chemicals that inhibit the growth of nearby plants. These chemicals can negatively affect basil, stunting its growth and making it more vulnerable to disease. The strong fragrance of rue can also interfere with basil's ability to thrive.
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Planting tip: If you’re growing rue, keep it well away from basil to prevent it from harming your plants. It’s best to plant rue in a separate garden bed or container.
2. Sage (Salvia officinalis)
Sage is a popular herb, often planted alongside basil due to its similar culinary uses. However, this combination can lead to problems.
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Why it's bad: Both sage and basil have similar growing needs, but sage is often more aggressive in the garden. It can compete with basil for space, nutrients, and water, causing basil to struggle. Additionally, sage can release substances that inhibit the growth of nearby plants, including basil.
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Planting tip: If you want to grow both herbs, give them enough space in your garden to avoid competition. But for the best results, it’s advisable to plant sage in a different area away from basil.
3. Cabbage and Other Cruciferous Vegetables (Brassica spp.)
Cruciferous vegetables like cabbage, broccoli, and kale are staples in many gardens, but they are not ideal companions for basil.
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Why they’re bad: Cabbages and other members of the Brassica family are heavy feeders, meaning they consume a lot of soil nutrients, especially nitrogen. This can leave basil with fewer resources to grow, ultimately stunting its development. Additionally, cabbage and other cruciferous plants often attract pests, such as aphids, which can also target basil.
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Planting tip: Keep cruciferous vegetables separate from basil and ensure there’s adequate space between plants. Consider planting them in separate garden beds to reduce the risk of pest infestations.
4. Fennel (Foeniculum vulgare)
Fennel is an aromatic plant with feathery leaves and yellow flowers, often used in cooking or as an ornamental plant. However, it’s not a good companion for basil.
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Why it’s bad: Fennel produces chemicals that can inhibit the growth of surrounding plants, including basil. It’s allelopathic and can significantly stunt the growth of basil if planted too close. Fennel’s root system is also quite extensive and can outcompete basil for space and resources.
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Planting tip: Keep fennel in a separate area of the garden, preferably in a pot, to prevent it from affecting nearby plants like basil. This way, you can still enjoy its beauty and aroma without harming your basil.
5. Mint (Mentha spp.)
Mint is another herb that can easily overrun your garden if not properly contained. Though it’s useful in culinary dishes, mint can be harmful to basil when planted nearby.
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Why it’s bad: Mint is highly invasive and spreads quickly through its roots, which can smother basil and take over garden beds. Mint competes for space, nutrients, and water, leaving basil with insufficient resources for healthy growth.
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Planting tip: If you want to grow mint, plant it in containers or raised beds to control its spread. Avoid planting mint directly in the ground next to basil to prevent it from overtaking your herb garden.
6. Thyme (Thymus vulgaris)
Thyme is a hardy herb that grows well in full sun, much like basil. However, it’s not always the best companion for basil.
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Why it’s bad: Though thyme and basil share similar growing conditions, thyme can be quite aggressive and may outcompete basil for water and nutrients. Thyme’s deep root system may also draw nutrients and moisture from the soil that basil needs for optimal growth.
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Planting tip: If you grow thyme, give it its own space in your garden to ensure both plants have enough room to grow. Plant thyme away from basil to prevent competition and maximize both plants’ health.
7. Carrots (Daucus carota)
Carrots and basil don’t mix well in the garden, though they may seem like compatible plants at first glance.
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Why they’re bad: Carrots are root vegetables, and their deep-growing roots can compete with basil’s shallow roots for nutrients and water. Additionally, carrots can attract pests like root flies, which can also affect basil’s root system.
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Planting tip: To avoid competition, plant carrots in a separate bed or row from basil. This will ensure that both plants have the space and resources they need to grow well.
8. Tomatoes (Solanum lycopersicum)
Tomatoes and basil are often paired together in the kitchen, but these two plants may not always make good garden companions.
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Why they’re bad: Tomatoes and basil have similar nutrient and water needs, but tomatoes are typically larger and can overshadow basil. They also attract pests and diseases, such as aphids and blight, which can spread to basil. Additionally, tomatoes may require more water than basil, leading to overwatering and potential root rot for the basil plant.
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Planting tip: While tomatoes and basil can be grown near each other, it’s best to space them apart to reduce the risk of disease transfer. Be sure to meet the water and soil needs of both plants separately.
9. Potatoes (Solanum tuberosum)
Potatoes are another plant to avoid growing near basil.
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Why they’re bad: Potatoes, like tomatoes, are heavy feeders and can deplete the soil of essential nutrients, leaving basil with fewer resources to grow. Additionally, potatoes attract pests like aphids and beetles, which can also target basil, leading to pest infestations.
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Planting tip: To minimize competition and pest issues, plant potatoes away from basil. Keep them in separate garden areas where they can grow without competing for nutrients or attracting pests to basil.
10. Peppers (Capsicum spp.)
Peppers are often seen as a suitable companion for basil, but there are a few reasons why they may not always work well together.
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Why they’re bad: Like tomatoes, peppers share many of the same growing requirements as basil. However, peppers can overshadow basil, leading to competition for nutrients and space. Peppers also attract aphids and other pests that can spread to basil.
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Planting tip: To avoid competition, plant peppers in a different part of your garden from basil. This will help both plants grow to their full potential without struggling for resources.
Conclusion
While basil is a versatile herb, it’s essential to be mindful of the plants you choose to grow alongside it. Some plants, such as rue, fennel, and mint, can hinder basil’s growth, while others, like tomatoes and potatoes, compete for nutrients and attract pests. By avoiding these bad companions and selecting plants that complement basil’s growth, you can create a thriving garden that supports healthy, vibrant basil plants. Ensure your basil has enough space and resources to grow, and your herb garden will be both beautiful and productive.