Tomatoes thrive when planted away from certain plants that can stunt their growth, attract pests, or compete for nutrients. Understanding these companion planting principles helps ensure a bountiful harvest of delicious, healthy tomatoes.

What Plants Should You Avoid Planting Near Tomatoes?

When planning your vegetable garden, it’s crucial to know which plants can negatively impact your tomato plants. Certain vegetables and herbs can inhibit growth, attract harmful pests, or even spread diseases. Avoiding these specific pairings will significantly improve your tomato yield and overall plant health.

The Brassica Family: Broccoli, Cabbage, and Cauliflower

Plants in the Brassica family, such as broccoli, cabbage, cauliflower, and Brussels sprouts, are generally not good companions for tomatoes. These vegetables are heavy feeders and can compete fiercely with tomato plants for essential nutrients in the soil.

Furthermore, Brassicas can attract specific pests that might also bother tomatoes. For instance, the cabbage worm, while not directly targeting tomatoes, can be a sign of a generally pest-prone garden. This competition for resources and potential pest overlap makes them poor neighbors.

Corn: A Nutrient Competitor

Corn is another plant that tomatoes generally do not like to grow with. Both corn and tomatoes are heavy feeders, meaning they require a significant amount of nutrients from the soil to thrive. Planting them too close together leads to intense competition for these vital resources.

This nutrient depletion can result in stunted growth for both plants. The corn may not reach its full potential, and your tomato plants might produce fewer, smaller fruits. It’s best to give both of these popular garden crops ample space and separate planting locations.

Fennel: A Known Inhibitor

Fennel is widely recognized as a plant that tomatoes dislike growing near. It is believed that fennel releases certain compounds into the soil that can inhibit the growth of many other plants, including tomatoes. This allelopathic effect can cause significant stress to tomato seedlings.

While fennel has its own gardening benefits, such as attracting beneficial insects, its negative impact on tomatoes is well-documented. Gardeners often report poor germination and stunted growth in tomatoes planted in close proximity to fennel.

Potatoes: A Shared Disease Risk

Potatoes and tomatoes share a common enemy: late blight. This devastating fungal disease can affect both plants, and planting them together increases the risk of the blight spreading rapidly. If one crop gets infected, the other is highly susceptible.

Late blight can wipe out an entire crop in a matter of days, especially in humid conditions. To protect your tomato harvest, it’s advisable to keep potatoes in a separate area of the garden. This separation is a crucial step in disease prevention.

Walnuts: Toxic Neighbors

While not a vegetable, walnut trees pose a significant threat to nearby plants. Walnut trees, particularly black walnuts, release a chemical called juglone from their roots, leaves, and bark. This compound is toxic to many plants, including tomatoes.

Juglone can cause wilting, yellowing leaves, and even death in sensitive plants like tomatoes. If you have a walnut tree in your yard, it’s best to plant your tomatoes a considerable distance away, or avoid planting them in that area altogether.

Why Does Companion Planting Matter for Tomatoes?

Understanding what tomatoes don’t like to grow with is a key aspect of companion planting. This gardening practice involves strategically placing different plants near each other to promote growth, deter pests, and improve soil health.

When you choose the right companions, you can create a more harmonious garden ecosystem. This leads to healthier plants, reduced need for pesticides, and ultimately, a more abundant harvest. Conversely, poor companion choices can lead to a weaker garden, more pests, and disappointing yields.

Nutrient Competition

As mentioned, some plants are heavy feeders and can deplete the soil of essential nutrients that tomatoes need. Tomatoes require a good balance of nitrogen, phosphorus, and potassium, along with various micronutrients. Planting them with other demanding crops leads to a race for these resources.

This competition can result in stunted growth, fewer flowers, and smaller fruit. It’s like trying to feed two growing children with only enough food for one; both will likely end up undernourished.

Pest and Disease Transmission

Certain plants can attract pests that also target tomatoes, or they might harbor diseases that can easily spread. For example, the tomato hornworm is a common pest, and while it primarily targets tomatoes, other plants in close proximity might attract generalist predators that can then find your tomatoes.

More critically, diseases like early blight and late blight can affect solanaceous plants (the nightshade family, which includes tomatoes and potatoes). Planting susceptible plants together creates a breeding ground for these pathogens.

Allelopathic Effects

Some plants release chemical compounds into the soil that can inhibit the growth of other plants. Fennel is a prime example, but other plants can also have similar, though perhaps less potent, effects. This is known as allelopathy.

These chemicals can interfere with seed germination, root development, and overall plant vigor. It’s a subtle but significant factor in garden success.

What Does Grow Well With Tomatoes?

While it’s important to know what to avoid, it’s equally beneficial to know which plants are good companions for tomatoes. These beneficial pairings can help deter pests, attract pollinators, and even improve the flavor of your tomatoes.

Some excellent companions include:

• Basil: Repels tomato hornworms and whiteflies. Many believe it improves tomato flavor.
• Marigolds: Known to deter nematodes in the soil and other pests.
• Carrots: Their deep roots help aerate the soil, which benefits tomatoes.
• Onions and Garlic: Their strong scent can deter pests like aphids.
• Borage: Attracts pollinators and is thought to deter tomato hornworms.

By strategically planting these beneficial herbs and vegetables, you can create a more resilient and productive tomato patch.

People Also Ask

### What vegetables should not be planted next to tomatoes?

Tomatoes should not be planted next to corn, as both are heavy feeders and compete for soil nutrients. Brassicas like broccoli and cabbage can also compete and attract pests. Potatoes share a risk of late blight disease. Fennel is known to inhibit tomato growth due to chemical compounds it releases.

### Can I plant tomatoes and peppers together?

Yes, tomatoes and peppers can generally be planted together. Both belong to the nightshade family (Solanaceae) and have similar growing needs. They don’t typically compete aggressively for nutrients and don’t share major disease vulnerabilities that would make co-planting risky.

### What herbs are bad for tomatoes?

Fennel is the primary herb widely considered bad for tomatoes due to its allelopathic properties that inhibit growth. While most other common culinary herbs like basil, mint, and rosemary are beneficial or neutral, fennel stands out as a plant to keep separate from your tomato plants.

### Why are my tomato plants not growing well?

Several factors can cause tomato plants to not grow well. These