Certain plants can hinder tomato growth, attract pests, or compete for nutrients. To ensure a thriving tomato harvest, avoid planting tomatoes near brassicas like broccoli and cauliflower, as well as fennel, corn, and walnut trees. These companions can negatively impact your beloved tomato plants.

Why Companion Planting Matters for Tomatoes

Companion planting is an age-old gardening technique that leverages the natural relationships between plants. When done correctly, it can enhance growth, deter pests, and improve soil health. However, some plant pairings can be detrimental. Understanding what not to plant near your tomatoes is just as crucial as knowing what to plant.

Plants That Stunt Tomato Growth

Some plants release substances into the soil that can inhibit the growth of tomatoes. Others directly compete for essential resources like water and nutrients.

• Brassicas (Cabbage Family): Plants like broccoli, cauliflower, kale, and Brussels sprouts are heavy feeders. They deplete the soil of nutrients that tomatoes also need. Additionally, brassicas can attract certain pests that may transfer to your tomato plants.
• Fennel: This aromatic herb is known to inhibit the growth of many garden plants, including tomatoes. It releases certain compounds that are toxic to tomato seedlings and can stunt their development.
• Corn: While seemingly a good companion, corn can attract the corn earworm, which is also a significant pest for tomatoes. Planting them together increases the risk of infestation for both crops.
• Walnut Trees: If you have a walnut tree on your property, avoid planting tomatoes anywhere near its drip line. Walnut trees release a substance called juglone, which is toxic to many plants, including tomatoes.

Pests and Diseases to Avoid

Certain plants can attract pests or harbor diseases that are harmful to tomatoes.

• Potatoes: Potatoes are susceptible to late blight, a devastating fungal disease that can easily spread to tomato plants. Since tomatoes and potatoes are in the same family (Solanaceae), they share many of the same pests and diseases.
• Eggplant: Similar to potatoes, eggplant can also attract potato beetles and is susceptible to verticillium wilt, a soil-borne disease that affects tomatoes.
• Dill: While often recommended for other vegetables, dill can attract spider mites and aphids, which can then move to your tomato plants. It can also attract swallowtail butterflies, whose caterpillars (cabbage worms) can damage tomato foliage.

Competition for Resources

Some plants simply require the same nutrients or water as tomatoes, leading to competition that benefits neither.

• Tomatoes are heavy feeders. They require ample nitrogen, phosphorus, and potassium. Planting other voracious eaters nearby can lead to nutrient deficiencies, resulting in stunted growth and poor fruit production.
• Water competition is also a significant issue, especially during dry spells. Ensure your tomato plants have adequate space and aren’t competing with large, thirsty plants for moisture.

Plants to Keep Away from Your Tomato Patch

Here’s a quick reference guide to some of the common garden inhabitants you should avoid planting in close proximity to your tomatoes.

Why These Combinations Don’t Work

The reasons behind these unfavorable pairings are rooted in plant biology and ecology.

Nutrient Depletion: Plants like broccoli and kale are notorious for their high nutrient demands. They can quickly deplete the soil, leaving tomatoes with insufficient food to produce healthy fruits. This leads to yellowing leaves and reduced yield.

Pest and Disease Transmission: Tomatoes, potatoes, and eggplants are all part of the Solanaceae family. This shared heritage means they are susceptible to the same pests and diseases. Planting them together is like rolling out the red carpet for blight and wilts.

Allelopathy: Fennel is a prime example of a plant that exhibits allelopathy. It releases chemicals that actively inhibit the growth of other plants. This is a survival mechanism to reduce competition for resources.

Predator Attraction: While some insects are beneficial, others can be detrimental. Planting corn near tomatoes can attract the corn earworm, a pest that readily switches to tomato plants.

What About Plants That Are Good Companions?

While avoiding certain plants is key, knowing your beneficial companions can significantly boost your tomato success. Herbs like basil, mint, and parsley can deter pests. Flowers such as marigolds and nasturtiums attract beneficial insects and repel nematodes.

Benefits of Good Companion Planting

• Pest Deterrence: Certain plants release scents that repel common tomato pests like aphids and whiteflies.
• Attracting Beneficial Insects: Flowers can draw in pollinators and predatory insects that feed on pests.
• Improving Soil Health: Some plants can fix nitrogen in the soil, benefiting nearby tomatoes.
• Enhancing Flavor: Anecdotal evidence suggests some companions can improve the taste of tomatoes.

People Also Ask

### What herbs should not be planted near tomatoes?

You should avoid planting fennel near tomatoes, as it can inhibit their growth. Dill can also be problematic as it may attract spider mites and aphids, which can then transfer to your tomato plants.

### Can I plant basil near tomatoes?

Yes, basil is considered an excellent companion plant for tomatoes. It is believed to deter tomato hornworms and whiteflies, and some gardeners swear it improves tomato flavor.

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

Avoid planting potatoes and eggplant next to tomatoes. These plants are in the same family and share common pests and diseases like blight and wilts. Brassicas like broccoli and cauliflower should also be avoided due to heavy nutrient competition.

### Are tomatoes and corn good neighbors?

No, tomatoes and corn are generally not considered good neighbors. Corn can attract the corn earworm, a pest that also readily feeds on tomato plants, increasing the risk of infestation for both crops.

### What plants repel tomato pests?

Marigolds are well-known for repelling nematodes in the soil. Basil can deter tomato hornworms and whiteflies. Nasturtiums can act as a trap crop for aphids and also deter some beetles.

Conclusion and Next Steps

By understanding which plants to keep out of your tomato patch, you are taking a significant step towards a healthier, more productive garden. Avoiding brassicas, fennel, corn, potatoes, and eggplant will help prevent nutrient competition, pest infestations, and disease spread.

Ready to plan your