Companion Planting: Eliminating the Need for Pesticides

Companion Planting: I’ve been spending a lot of time recently reading about the use of pesticides in commercial agriculture. It seems there’s a furore going on about whether it’s good and whether the pesticides used on organic crops are better or worse. As you might expect, there are experts sitting on both sides of the fence, and those choosing to sit right in the middle. I guess it’s up to us as consumers to decide for ourselves which is right. 

By Dawn Cowles

I, for one, have decided that while both man-made and natural pesticides have their pros and cons, I will circumvent the whole issue by growing my own fruit and veg. I’ll be looking to mother nature to help me keep those pesky pests at bay. How am I planning to do it? With the help of companion planting. But before I share some ideas, let’s look at why they use pesticides in commercial farming.

Companion Planting: Organic Fruits and Vegetables Market

The Problem of Pesticides

Why Has Commercial Agriculture Come to Rely on Pesticides?

Pesticides have been used for thousands of years. There’s evidence, for example, that the Roman’s used ashes, crushed cypress leaves and diluted urine to protect their crops. 

The problem with pesticides today is that modern commercial agriculture relies on them heavily. More than 1 billion pounds of pesticides, for example, are applied to crops in the US every year. Our escalating use of pesticides has become a public health hazard, is disastrous for the environment, and has caused the evolution of superweeds which require ever more toxic pesticide formulas to kill them. 

But why do producers use them if they’re considered to be so bad? They use them because it means they can increase their yields and improve revenue. If they didn’t use pesticides, there would be an increased risk of losing a crop because of pests and diseases.

Let’s not forget as well, the multi-billion dollar agrochemical industry that has a huge impact on the continued use of pesticides around the world. The agrochemical industry has far-reaching political power, particularly in the US. With the money and influence to lobby Congress this industry can keep regulation of pesticides and practices extremely limited. 

The agrochemical industry is also very influential in the area of scientific research that guides policy making. It provides the lion’s share of funding, thereby influencing what does and doesn’t get investigated and even withholding results if they don’t like the outcome.

All that being said, decades of sound research has shown there is a definite link between the use of pesticides and long-term detrimental health impacts on humans and the environment. 

The Health Impacts of Pesticides

  • Can increase the risk and can cause certain types of cancers.
  • Can lead to severe respiratory problems.
  • Might cause kidney damage and lead to kidney disease.
  • Can cause cognitive decline and lead to brain disorders.
  • Can cause severe birth defects.
  • Can increase the risk for developing autism.
  • Can have lasting and disrupting effects on your hormones.

The Environmental Impacts of Pesticides

  • They kill important pollinators such as honey bees.
  • Excessive pesticide use disrupts the food chain and essential ecosystems.
  • They reduce the quality of the soil and degrade the nutritional content of food.
  • They contaminate the water supply.
  • They are bad for farmworkers. 

One way to get around the whole problem of pesticides in your food is to grow your own and use natural pesticides as much as possible. You can do this by making homemade pesticides that won’t harm the environment or your own health. It’s also possible to use certain insects as predators against some pests in your garden. I’ll be looking at some of these options in later articles because for now I want to concentrate on companion planting. 

What is Companion Planting?

Do you have a companion in your life right now? I know I do. If you do, what was it about them that made you choose them? Was it their caring and understanding nature? Was it that they were a little different and complemented you perfectly? Or was it the colour of their eyes you simply couldn’t resist? We’re very lucky that we can choose our own companions, plants, on the other hand, don’t have it so good.

In our gardens, in particular, they get plonked in the ground wherever we see fit. I’m a prime example of people planting something just because there was a space. Until now, I’ve given little thought to soil conditions, the availability of light, colour combinations, and whether plants can be beneficial partners. This year, that’s about to change and I’m starting with companion planting. 

Companion planting is a way of maximising growth and crops by planting mutually beneficial plants next to each other. 

What Are The Benefits of Companion Planting?

There are many reasons to start companion planting:

  • Pest prevention: A companion plant might protect its partner from pests that are typically attracted to it.
  • Improved soil fertility: Nitrogen-fixing plants can help our non-nitrogen fixing plants.
  • A natural trellis: tall plants can help provide scaffolding for climbing plants.
  • Regulating shade: low shade-loving plants can get protection from tall sun-loving plants.
  • Weed control: you can discourage weeds from growing around upright, thin plants by planting wide ground-covering plants.

Three Sisters Planting

Almost every article I read online mentioned something called three sisters planting. It’s an example of companion planting that the Native American’s have been practising for centuries. The three sisters in question are sweetcorn, climbing beans, and squash or pumpkin. Several Native American tribes used this planting trio because they thrived exceedingly well together.

They plant the corn first and as the older sister it offers support for the beans. The beans pull nitrogen from the air and bring it to the soil for the benefit of all the sisters. As they grow the beans wind their way up the corn stalks and hold the sisters together. The large pumpkin leaves protect the roots of the sisters by creating a living mulch to shade the soil. The leaves help to keep the soil cool and moist while also preventing weeds.      

Some Companion Planting Suggestions

The list of companion planting suggestions is as long as your arm. There’s not enough room here to include them all so let’s look at some common garden plants and possible companions.


Basil and tomatoes is a match made in heaven, not just in the kitchen but in the garden too. This pungent herb not only repels flies and mosquitoes, it also improves the tomatoes yield. Another great companion for tomatoes are marigolds. They repel several garden pests including nematodes. Other companions for tomatoes include:

  • Asparagus
  • Carrots
  • Celery
  • Lettuce
  • Parsley
  • Spinach
  • Members of the onion family 

Cabbage, beets, fennel, dill, peas, and rosemary are not good bedfellows for tomatoes. Potatoes and corn should also be grown far away from your tomatoes. 


Good neighbours for peas are beans, carrots, cucumbers, corn, radishes, and turnips. Chives are also a good companion because they ward off aphids. If you want to improve the flavour and health of your peas, consider planting mint nearby. 

For a natural trellis for your peas, plant corn or sunflowers. 


A good companion for peppers is basil. It helps to repel aphids, mosquitoes, flies, and spider mites. There’s also a school of thought that thinks basil improves the flavour of the peppers. Might have to do some A/B testing of my own to see whether there’s any truth in that statement. Onions, tomatoes, and spinach also make good companions for peppers.

Keep peppers away from beans to avoid the bean vines getting tangled in the pepper plants.

Green Beans

If you don’t want to go to the bother of building a trellis for your beans plant them in amongst corn. The beans also help out the corn by fixing nitrogen in the soil. To help keep the pests away from your beans you can plant marigolds, nasturtiums, summer savory, and rosemary. These flowers and herbs repel bean beetles. Other companions include:

  • Brussel sprouts
  • Broccoli
  • Other members of the cabbage family
  • Cucumbers
  • Peas
  • Potatoes
  • Radishes

Beans don’t like to grow alongside beets or members of the onion family.


Good companion plants for cucumbers include:

  • Beans
  • Celery
  • Corn
  • Dill
  • Lettuce
  • Peas
  • Radishes

Plant marigolds and nasturtiums to repel aphids and beetles.

One plant you should not plant near your cucumbers is sage. It can stunt the growth of the cucumbers. 


Plant carrots near onions because the onions will repel carrot fly. Onions are also a very effective aphid deterrent, which makes them perfect for planting alongside plants that are prone to aphid infestations. Cabbage, lettuce, parsnips, tomatoes and beets are also good companions for onions. Rosemary, marjoram, and savory are good herbs to grow alongside. 

Keep your onions away from peas, beans, and asparagus.   


A common problem if you grow lettuce, particularly in the UK, has to be slugs. Thankfully slugs aren’t a problem here in Bulgaria. It’s not wet enough and probably too hot. Nevertheless, I like the idea of planting mint among the lettuce, together with chives and garlic to repel aphids. Other good companion plants include:

  • Beets
  • Beans
  • Broccoli
  • Corn
  • Carrots
  • Radishes
  • Peas 

And let’s not forget the veg gardeners favourite flower the marigold. 

It doesn’t seem like lettuce has many plants it doesn’t get along with apart from parsley, and that’s only because it might have a tendency to crowd the lettuce out. 


Carrots don’t like the heat which for me means growing them in the spring and autumn. I didn’t realise, until doing my research, that they can grow well when planted in among tomatoes. It not only provides much needed shade, it also produces a natural insecticide called solanine. This natural insecticide targets pests that are a problem for carrot plants. 

The relationship between tomatoes and carrots is not one-sided. The tomatoes benefit from the carrots because they aerate the soil around the roots of the tomato, letting more air and water reach the roots. 

Leeks also make good companions for carrots, together with rosemary, sage, and chives. 


I love growing radishes because you get a crop within 30 days. None of that waiting around for months and having to lavish it with loads of attention. I like the idea of planting them among carrots. You harvest them before the carrots, so they loosen the soil for the carrots just as they’re about to take off. Radishes also have several other friends such as:

  • Onions
  • Beets
  • Cabbage
  • Lettuce
  • Spinach
  • Kale
  • Squash 

The only plant radishes don’t get along with is hyssop.  


A favourite bedfellow for sweetcorn is something that fixes nitrogen in the soil. Hence the reason beans make such good companions. Sweetcorn also makes a great natural trellis for cucumbers, peas, pumpkins, and melons. Courgettes also grow well planted among sweetcorn. 

Tomatoes and corn shouldn’t be planted close together because corn earworms can attack both of them. 

Companion Planting Herbs

I’ve become a big fan of herbal teas in recent years, after ditching caffeine, but hadn’t thought of growing them in amongst my vegetables. I will try a few of the following suggestions this year.

  • Rosemary: Deters bean beetles, cabbage moths, and carrot flies.
  • Parsley: Plant near asparagus, corn, and tomatoes.
  • Oregano: Good to plant amongst all vegetables.
  • Mint: Deters white cabbage moths.
  • Chives: Good to plant with carrots.
  • Basil:  repel flies and mosquitoes from your tomato plants. 

If you want to know more about companion planting, there’s a fantastic list on The Old Farmer’s Almanac website.

I, for one, will be putting some of these companion suggestions into practise this year. We’ve got an aim here in Bulgaria for the coming year. To grow everything we need to eat (fruit and vegetable wise) in our garden. It will be a lot of hard work but it will be worth it. I hope you’ve enjoyed reading this article, and it inspires you to get out there and get your hands dirty. Even if you’ve just got a small patio, there are plenty of opportunities for growing some of your own food. 

Managing pests in an organic garden is a complex and challenging–though often rewarding–endeavour, depending just as much on patience, trial-and-error, and the understanding of local types of soil and insects as it does on time-honoured traditions and universal rules-of-thumb. Had success or failure with companion planting? Learned any techniques in your own garden that might be useful to others? Wish to share any deeper understanding of the complex interactions between plants? Share your thoughts in the comments section below, leave a comment on this article’s Facebook post, or reply on Twitter.

Want to know more? The team at First Tunnels has also produced an excellent companion planting guide.