When planning your garden, understanding what not to plant next to certain vegetables and herbs is crucial for a thriving ecosystem. Companion planting involves strategically placing plants together to deter pests, attract beneficial insects, and improve soil health, while avoiding detrimental combinations that can stunt growth or invite disease.

The Art of Companion Planting: What to Avoid in Your Garden

Successful gardening isn’t just about what you plant, but also where you plant it. Certain plant pairings can lead to competition for resources, attract pests to vulnerable neighbors, or even release chemicals that inhibit growth. Learning these "don’ts" is as important as knowing the "dos" for a bountiful harvest.

Why Plant Combinations Matter

Every plant has unique needs and interactions with its environment. Some plants are natural allies, offering protection or nutrients to their neighbors. Others, however, can be detrimental, creating an unfavorable environment that leads to poor yields and increased susceptibility to pests and diseases.

Avoiding Plant Rivals

Just like people, some plants simply don’t get along. This incompatibility can stem from several factors:

• Nutrient Competition: Some plants are heavy feeders, depleting the soil of essential nutrients that their neighbors need. For example, corn is a very hungry plant and can deplete nitrogen from the soil, affecting beans that also need nitrogen.
• Pest and Disease Attraction: Certain plants can act as magnets for specific pests or diseases. Planting them near susceptible crops can lead to an infestation that devastates your garden. For instance, planting brassicas (like broccoli and cabbage) together can concentrate cabbage worms.
• Allelopathy: Some plants release biochemicals into the soil that can inhibit the growth of other plants. This is a natural defense mechanism that can be a gardener’s worst nightmare if not understood.
• Root System Interference: Plants with aggressive or sprawling root systems can crowd out or damage the roots of their neighbors, limiting their access to water and nutrients.

Common Garden Pairings to Avoid

Understanding specific plant dislikes can save you a lot of gardening heartache. Here are some common vegetables and herbs that generally do not fare well when planted next to each other:

Brassicas (Cabbage Family)

The brassica family, which includes broccoli, cauliflower, cabbage, kale, and Brussels sprouts, are notorious for attracting a variety of pests, especially the cabbage worm. Planting them in close proximity can create a buffet for these hungry caterpillars.

• Avoid planting near: Strawberries, tomatoes, pole beans, and most herbs.
• Why? Strawberries can be susceptible to similar fungal diseases. Tomatoes can attract blight that may spread. Pole beans are nitrogen fixers, and brassicas don’t benefit from this in the same way.

Legumes (Beans and Peas)

Beans and peas are nitrogen fixers, meaning they enrich the soil with nitrogen. While beneficial for many plants, they can be detrimental to those that prefer lower nitrogen levels or are susceptible to fungal diseases exacerbated by excess moisture that legumes can encourage.

• Avoid planting near: Onions, garlic, chives, and other alliums.
• Why? Alliums can inhibit the growth of beans and peas. Conversely, beans can stunt the growth of alliums.

Alliums (Onions, Garlic, Chives)

These pungent plants are often used as pest deterrents, but they can be too aggressive for some garden companions. Their strong scent can overwhelm or inhibit the growth of certain vegetables.

• Avoid planting near: Asparagus, beans, peas, and cabbage family plants.
• Why? Alliums can stunt the growth of asparagus and legumes. They can also attract pests that harm cabbage family plants.

Tomatoes

Tomatoes are susceptible to various fungal diseases like blight, and certain companions can exacerbate these issues or compete heavily for resources.

• Avoid planting near: Brassicas, corn, and dill.
• Why? Brassicas can attract pests that also affect tomatoes. Corn can compete for nutrients and may host pests that damage tomatoes. Dill can attract spider mites and can stunt tomato growth.

Cucumbers and Melons

These vining plants require ample space and can be susceptible to powdery mildew. Certain companions can worsen these issues.

• Avoid planting near: Potatoes and aromatic herbs like sage.
• Why? Potatoes can attract blight that affects cucumbers. Sage can stunt the growth of cucumbers and melons.

Strategic Planting for Success

Understanding these negative pairings allows for more strategic garden planning. Instead of just planting what you want, consider the needs and interactions of each plant.

Example of a Bad Pairing: Planting a row of broccoli right next to a row of pole beans. The broccoli will attract cabbage worms, and the beans, while nitrogen fixers, might not thrive in the same microclimate as the brassicas, and the pests can easily move between them.

Example of a Good Pairing: Planting basil near tomatoes. Basil is believed to deter tomato hornworms and whiteflies, while also improving tomato flavor.

Companion Planting Considerations

People Also Ask

What vegetables should not be planted together?

You should avoid planting brassicas near strawberries or tomatoes, legumes near onions or garlic, and tomatoes near brassicas or corn. These combinations can lead to increased pest infestations, disease spread, or stunted growth due to nutrient competition or allelopathic effects.

Can I plant basil next to tomatoes?

Yes, planting basil next to tomatoes is generally considered a beneficial companion planting strategy. Basil is thought to deter pests like tomato hornworms and whiteflies, potentially improving tomato health and yield.

Why shouldn’t I plant onions and beans together?

Onions and beans are not good companions because alliums like onions can inhibit the growth of beans and peas. Conversely, beans can sometimes stunt the growth of onions. They compete for resources and can negatively impact each other’s development.

What is the worst companion plant for tomatoes?

While several plants can be problematic, brassicas are often cited as poor companions for tomatoes. They can attract pests that also affect tomatoes, and some gardeners report that brassicas can stunt tomato growth due to competition or allelopathic interactions.

Can dill be planted near tomatoes?

No, dill is generally not recommended to be planted near tomatoes. Dill can attract spider mites, which can harm tomato plants, and it is also believed to stunt the growth of tomatoes. It’s best to keep a good distance between these two.

By understanding these plant relationships, you can create a more harmonious and productive garden.