Growing basil as a companion plant to bok choi

Basil As A Companion Plant: 5 Plants You Can Grow With Basil For Best Results.

Basil is a wonderful herb that can be grown indoors and outdoors. It grows relatively quickly compared to many other herbs. Although there are several benefits to growing basil, some gardeners love it as a companion plant for other veggies and herbs.

Companion planting isn’t a modern agricultural development. In the US, the practice of growing squashes with corn and green beans (the three sisters’ cultivation) was there even before the Europeans arrived on the continent. In China, rice crops were cultivated with azole to fix nitrogen in the soil and block sunlight for other competing plants.

We then began planting herbs along with other plants. Most herbs have a distinct scent that repels insects, and with fewer insects, there are fewer diseases. This is the prime reason why we plant basil as a companion plant.

Reasons to do companion planting with basil

Most basil’s properties are helpful for other plants, too. Although companion planting has several benefits, some aren’t relevant to basil. For instance, basil doesn’t suppress weeds or enhance the soil. Here’s why basil is a perfect friend for your garden.

1. Basil repels most insects

If you grow plants like chilies, you’ll see that ants and insects love being around them. These insects are a threat to the plant. Some, like ants, don’t mess with the plant, but they can bring harmful pathogens from other infected plants. For instance, ants may carry pathogens that cause downy mildew in basil and kill the plant.

Basil’s scent is a mild repellant for ants. Yet, we can’t say basil cheeses every harmful inset miles away. Basil, too, gets infected. But its repellent effect would significantly improve the garden.

Although basil repels most insects, it doesn’t overdo it to the extent of eliminating bees and bugs that help pollination.

If you’re growing inside a polytunnel, greenhouse, or indoors, planting basils close to the windows and doors is a good idea. Insects will have difficulty climbing over the basil plant to reach other crops.

2. Basil flower attracts bees

While basil chases away many insects, it attracts many beneficial insects. When basil blooms, it attracts bees who come to drink nectar.

Most basil varieties flower at around four to six months. Some, like lemon basil, bloom faster, while the most common sweet basil takes time to produce flowers.

Yet, letting the basil plant bloom isn’t an excellent idea. Flowering and producing seeds may make the plant more mature. The leaves of a mature plant taste bland, and its aroma is not so strong.

To have an aromatic, flavourful basil plant, you must keep nipping the flowers as they appear. Also, as you harvest basil, you cut off the tip of each stem where basil flowers emerge.

Related: How often can we harvest basil?

3. Basil provides shade

Although plants depend on light to grow, not all plants need the same light. Basil is one of those plants that needs abundant sunlight. In hot, humid conditions with excellent direct sunlight, basil thrives. In calm and dim climates, basil growth tends to be stagnant.

Related: How Much Light Does Basil Need?

Conversely, some plants need shade. Mint, for instance, loves partial shade, although mint and basil belong to the same family. Popular herbs like Cilantro/Coriander, Lemon balm, Chives, and Parsley grow in shades too.

A good choice is to mix the two. You can plant basil alongside cilantro. Basil, which grows taller, gets the sun, while cilantro, which spreads wider, gets the shade from basil.

4. Maximum space utilization.

Gardners prefer to grow as much as possible in the given space. One excellent technique is to grow basil with other plants. Basil that grows taller doesn’t interrupt many other plants that grow in the ground. Thus, the other plant gets all the benefits we talked about before while we utilize the space to its fullest.

Five plants that grow well with basil as their companion

Basil rarely messes up with other plants. Some prefer to avoid basil’s company. Yet, the following benefits are incredibly beneficial when a basil plant is nearby.

1. Tomatoes

Many gardeners love tomatoes, and tomatoes love basil. Basil is a perfect companion plant for tomatoes for various reasons.

Most importantly, basil repels tomato hornworms and other destructive insect pests.

Basil and tomatoes don’t compete for nutrients. As basil is a leafy vegetative plant and tomatoes are primarily grown for fruits, they have different nutrient needs.

Secondly, tomatoes are giant plants with relatively fewer leaves. Likewise, basil is short and bushy. Thus, tomatoes and basil share the space very well.

Related: How to Grow Hydroponic Tomatoes Without Pollination

2. Root vegetables

Most root vegetables don’t have any scent. But when basil is around, they get an aromatic friend who protects them from insects. Root veggies like radishes, carrots, and potatoes grow well with basil. Sweet basil and radishes are a perfect combination.

Unlike herbs like mint, most root vegetables need light for better yield. Thus, growing basil and root vegetables together does not save much space. Each plant would need about one square foot of space to grow.

Yet root vegetables and basil use different nutrients, so there’s very little competition between them.

3. Cabbages

Cabbages and basil mutually enjoy each other’s insect-repellent properties. A compound found in cabbages, glucosinolates, and basil’s natural aroma produces a scent bugs hate. As a result, both plants experience fewer pests and diseases.

Many other plants in the cabbage family can be good partners with basil. For instance, broccoli, cauliflower, and Kale belong to the same cole crop family. They all produce glucosinolates and have the same effect.

4. Asparagus

Asparagus and basil do somewhat the opposite of what basil does with cabbage. Instead of chasing bugs, the combined scent of asparagus and basil attracts ladybirds.

Ladybirds are known to be natural predators of many other insects. Adults can feed on about 50-100 aphids daily, and a single ladybird larva can eat about 200 – 300 aphids in its lifetime.

Further, basil’s scent keeps the asparagus beetle away. This insect eats the young tips of asparagus shoots.

5. Mint

Mint and basil belong to the same family, Lamiaceae. Yet basil loves the sun, and mint can tolerate a bit of shade. Mints don’t grow taller; although basil grows bushy, it doesn’t spread in the ground. Thus, mint can take over the ground while basil grows taller, providing mint the shade it needs. Besides, mint’s flavor repels most of the basil’s common pests.

Worst companion planting with basil.

Basil goes well with many other plants, but not all of them. Some plants compete with basil, and either one may eventually lose in the battle. Here’s a list of such plants and why you shouldn’t grow them with basil.


Cucumbers are vegetative plants that grow tall—often taller than 12 feet. They block all sunlight from the tiny basil plant below, so basil that grows sideways may not stand a chance to grow. Further, the aroma of basil could degrade the taste of cucumbers, too.


Thyme grows well in dry, sandier soil. Basil, however, likes moist, nutrient-rich soil. Thus, basil and thyme can’t be grown together.


Gardners find Fennel toxic to many other plants. It’s a good idea to grow fennel as a monoculture. Basil next to a fennel plant may experience stunted growth.

Concerns about companion planting

Although companion planting has been practiced since humans started growing food, research on this is very limited. Most of these friendly plants were chosen based on several gardeners’ experiences, but a scientific study may change our perception.

Just because two plants have mutually beneficial properties doesn’t guarantee a successful growing season together. Other factors, such as crop density, ratio, and relative planting time, all impact yield and quality.

Questions like how many basil plants to have per every tomato plant, whether they should be 25 cm apart or 40 cm apart, whether they should be planted simultaneously, or whether the basil should be ready to welcome the tomato seedlings need to be tested scientifically.

Companion planting in hydroponics

The rules of companion planting change a bit in the hydroponics context. Notably, the competition for nutrients is almost irrelevant in hydroponics. Yet, other factors, like the root mass, nutrient mix, and the size of the companion plant, matter.

We grew basil with bok choi. They made a good combination. Basil kept the pests and bugs away, and bok choi grew healthy. Yet, they were both in the same Kratky container. The vigorous growth of bok choi soon took over the container. Even worse, the roots of bok choi grew too large, and it started drinking more nutrients than the basil. It forced us to transplant basil into a new container.

One more thing to consider is the nutrient mix and EC level. Basil grows well at around 1.5 – 2.4 EC. Yet most leafy vegetables like lettuce grow at 0.8 -1.5. Fruiting plants like tomatoes need about 3.5 -4.0 EC when they fruit. We’ve noticed basil tolerates high EC than low EC. Thus, you may grow basil and tomatoes at the same nutrient concentration. But, if you try to grow them with lettuces, basil leaves turn yellow, their growth will be stunted, and their flavor and aroma, too, will be lost.

Finally, when choosing a companion plant for basil, you should also know about the hydroponic system you’re using. We’ve already discussed how bok choi drank more nutrients than basil in a Kratky container. Likewise, if you’re growing basil in NFT along with a larger plant like tomato, tomato roots may grow faster and take up the entire NFT channel.


Basil is an excellent herb on its own. Besides, it makes an excellent choice as a companion plant for many. Its insect-repelling property is one of the prime reasons basil makes friends in the garden. Although basil grows well with many, there are some plants we need to avoid as well. Further, you may have to think differently if you companion plant basil in hydroponic systems.

This post has discussed a list of plants that grow well with basil and three that don’t. I hope it helps you grow an abundance of vegetables and herbs.

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