Some factors prevent or impede the development of both plants if placed side by side. 

However, under certain circumstances, both plants can also benefit each other. So, we are going to discuss what goes against the cultivation of tomato and cucumber plants next to each other and what favors their interplanting. 

Why Should You not Plant Cucumbers near Tomatoes?

Here are some reasons why planting cucumbers and tomatoes together is not a good idea.

Shared Diseases

Cucumber and Tomato plants share some common diseases that can be spread if both plants are positioned and grown close to each other. Planting the cucumber and tomato plants with sufficient gaps between them lowers the chances for these diseases to spread from one to another. 

Besides, these practices help reduce the risk of diseases being transmitted between cucumber and tomato plants by pests and other cross-plant infections. Let’s see what the major shared diseases are for both cucumber and tomato. 

Phytophthora Blight

This is a fungal disease, also known as “late blight,” that affects both the cucumber and tomato. Fungal infections like Phytophthora Blight are more likely to develop in environments with moisture. When tomato and cucumber plants are within proximity, air can’t circulate freely among the plants, causing the area to be damp and attracting these types of diseases.

Moreover, an infected plant serves as a source for the rapid spread of the disease to neighboring plants. Some common symptoms of Blight are dark, water-soaked lesions on the leaves, stems, and fruits, leading to rotting and decay. 

Bacterial Wilt 

Normally, cucumbers are likely to be infected by this bacterial disease. But, the diseased cucumber can also affect the surrounding tomatoes to a lesser extent. That’s why it can be a good idea to plant both cucumber and tomato crops away from each other. The main symptom of this bacterial disease is severe wilting of the vines, followed by rapid death of the plant.

Cucumber Mosaic Virus 

Another common shared disease of both cucumber and tomato is Cucumber Mosaic Virus. A pest called “Aphid” normally transmits this disease. When cucumber and tomato plants are cultivated near each other, this increases the chance of transmission of this disease.

Restrict Air Circulation

Both cucumbers and tomatoes have lush foliage. Therefore, closely planted cucumbers and tomatoes can actually limit the circulation of air. Proper airflow between the plants is crucial to prevent plants such as cucumbers and tomatoes from moisture-related diseases. 

When recommended plant-to-plant distance is maintained, it allows adequate air circulation among the plants, controlling the humidity level and preventing the buildup of moisture on the cucumber and tomato plant surface. Besides, lack of air circulation can hinder the movement of pollen, which is important for fertilization and fruit growth.

One key fact to keep in mind is that the reduction in air circulation can also obstruct the process of photosynthesis by diminishing the intake of carbon dioxide (CO2).

Compete with Each Other for Resources

Like every plant, tomatoes and cucumbers also get water and nutrients from the soil, which play a crucial role in their growth and development. But, if planted closely, both the plants can compete for nutrients and water. 

As a result, there is an increased risk of nutrient deficiencies in both plants. While you can plant them near each other, you have to maintain a minimal spacing. Twenty-four inches of distancing between cucumber and tomato plants is considered a safe spacing to prevent them from competing for resources.  

Benefits of Interplanting Tomatoes and Cucumber Plants

There are also a good number of reasons for tomato and cucumber plants to be cultivated side by side. We have seen what prevents planting them close to each other. But that doesn’t completely conclude that you can’t interplant them at all. 

If the place has enough sunlight, and the environment is favorable for both the plants, you can indeed interplant them. Here are some benefits of interplanting tomato plants and cucumber vines:

Common Growing Condition

Both tomato and cucumber plants prefer a substantial amount of direct sunlight daily. The exposure to the sun helps these plants grow and thrive. Also, the soil requirement for the plants is quite identical. 

That’s why both plants can be good companions of each other if interplanted. Moreover, they have different nutrient needs, so they don’t compete with each other for the same soil nutrients as much if adequate spacing is maintained. Cucumbers need more nitrogen, while tomatoes need more phosphorus and potassium. 

It can be a good idea to use composted cow manure combined with seaweed for tomatoes and provide a little extra nitrogen for cucumbers. This is because cucumbers thrive with more nitrogen than tomatoes. However, be cautious not to over-fertilize your tomatoes with excess nitrogen, as it can lead to excessive foliage growth and fewer fruits.

Growth Habit

The growth habits of cucumbers and tomatoes are also different but are complementary to each other. The cucumber vine grows and spreads horizontally, and the tomato plants have more vertical growth. That’s why they are less likely to be involved in competition for space due to their varied growth habits.

While both plants love to be under direct sunshine, tomatoes are sensitive to scorching heat and humid environments, which, by the way, the cucumber can endure. So, cucumber vines can provide enough shade to the tomatoes during extremely humid weather. 

The shade from cucumber vines helps keep the soil around the tomatoes slightly cooler and evenly moist. Tomato plants don’t do well when soils get too hot and dry out. Besides, their distinct growth helps you optimize the space of your garden. 

Trellis

Tomato plants have more upward development, while the cucumber is known for vining horizontally. Using a trellis to support the cucumber vine allows for vertical growth. And doing so can lead to a two- to threefold increase in cucumber crop production. 

Surprisingly, the upright tomato plant can act as a trellis for cucumbers to grow and thrive vertically, which will produce more yield compared to those spread horizontally. 

Can Tomatoes And Cucumbers Be Planted Side by Side?

While tomatoes and cucumber plants are not the best of companions, you can still plant them next to each other. We have discussed a good number of reasons why you should avoid planting neighboring tomatoes and cucumbers and also shed light on how they benefit each other after being planted together. 

Normally, if you want to plant tomatoes and cucumbers, you must follow and stick to the recommended spacing for both plants. Cucumber and tomato plants should be spaced between 20 to 24 inches apart. This spacing allows each plant to have sufficient room to grow, develop healthy foliage, and produce fruit without crowding.

Row spacing is also important if it concerns you. You keep a minimum 3 feet distance between each row of plants. Wider row spacing ensures that the plants have ample room to spread and promotes good air circulation, reducing the risk of fungal diseases.

What are the Best Companion Plants for Cucumbers?

Companion plants are various species of plants that can thrive and adapt successfully in each other’s presence. Companion plants not only avoid inhibiting the growth of nearby plants but also enhance each other’s development. They achieve this by avoiding competition for the same nutrients and offering pest protection.

Companion plants can be anything that helps in the growth of the main plant. It can be other vegetable plants like cucumber and tomato or can be flowers and herbs. Among vegetables, carrots and onions are good companions for cucumbers. 

The reason for them being friendly with cucumbers is that they don’t spread as much or compete for space with cucumbers. If you want the soil to be nutrient-rich for cucumber, you can consider some legumes like peas, corn, and beans. Their root system increases the nitrogen concentration in the soil, which is a key nutrient for cucumbers. 

Some flowers can also be a good neighbor of cucumbers as well. For example, the Marigolds flower can drive away harmful insects from the cucumber crop. Some similar companion flowers for cucumber are borage, sunflower, chives, etc. 

If you grow cucumbers in your landscape, utilizing these flowers can be an excellent addition to help in the growth of cucumbers and elevate the visual aesthetic of your landscape. 

What are the Best Companion Plants for Tomatoes?

Similarly to Cucumbers, you can choose the flowers, herbs, and vegetables that can be excellent neighbors of tomatoes. In fact, you can consider the companion plants based on the needs of your current tomato plant. 

For example, some flowers like Lavender and Sunflowers attract bees and butterflies and play a vital role in tomato pollination. And for controlling weeds, Crimson clover can be a wonderful addition.

Vegetables, to name a few, carrots and garlic can be examples of good companions of tomato. Carrots repel carrot flies, which can damage tomato plants and also help loosen the soil. On the other hand, garlic can discourage aphids and other insect pests that can harm tomatoes.

Conclusion

It is possible to cultivate tomato plants and cucumber vines alongside each other, but there are better approaches to gardening. If you have the opportunity to avoid interplanting tomatoes and cucumbers, it’s recommended to plant them separately. 

Nevertheless, if you choose to plant them together, maintaining proper spacing is essential. The condition of healthy growth for both cucumbers and tomatoes is similar. So, interplanting them can be feasible under the right conditions and in an appropriate environment. 

And lastly, this guide will enlighten you enough regarding the topic, and you can make a better decision in the end.