by Adrian White
20 December, 2021 by
Lucija Johum

Gardening and agriculture today are often dominated by one universal growing technique: monoculture. 

What is monoculture? To break down its meaning, “mono” means one, with “culture” being an extension of the word agriculture. Putting these together, this describes a growing technique that only involves the cultivation of one type of plant in an entire system.

We see it all over the country and around the world. Corn, soybeans, canola, wheat, cane sugar, and tobacco, grown with nothing else: no weeds, no other plants, and in perfectly manicured rows. It seems that cohorts of conventional agriculture have evidently figured out the best growing method out there. But have they really?

Enter companion planting, an exciting approach to farming and gardening catching on in popularity today. This method involves the integrated, cooperative interplanting of different botanical species together in one space so that they benefit each other with completely natural and supportive advantages.

While it’s finally picking up speed among gardeners and hobby growers everywhere as a trend, for a long time it’s gotten a bad rap as a fanciful method of gardening with no practical application. However, that couldn’t be farther from the truth. 

Ancient cultures have used companion planting for thousands of years in agricultural systems all around the world. Today, science is confirming a lot of its observed benefits.  But more specifically: companion planting can be of incredibly important use within a greenhouse structure, and for reasons that are a bit different from conventional outdoor growing or indoor growing.

We’ll take a look at all of them here.


Some monocultural growers’ arguments against companion planting may be that it is a time-consuming, tedious, and complicated method. Not only does it take more time and effort to nurture so many different kinds of plants (each with its own different needs), but one must also do research on what to plant with what, ensuring that the benefits are there in the first place.

Compared to planning a system for just a single species, companion planting can certainly sound more complex. But what many may not know is that companion planting provides tons of benefits – both to plants and the farmer – that monoculture completely lacks.


While monocultural growers are busy spraying crops with pesticides to keep away pesky bugs and other critters, a plot of co-beneficial companions can actually manage a great deal of these problems on its own. Where a glut of one species of plant may signal an all-you-can-eat buffet for surrounding pests, add another plant that repels or discourages these same bugs, and you strike a healthier balance and some natural protection – without the chemicals or costs.


On the opposite end of the spectrum, planting one plant with another type can bring insects into the picture that wouldn’t have been attracted to the situation otherwise. The best growers know that not all insects are pests. In fact, some are central to gardening success – think bees, but this category does not just limit itself to our honey-loving friends. Spiders, ladybugs, and even wasps can be beneficial presences, too.

Just imagine: a single plant is at the mercy of a voracious pest. Then, imagine planting it with a companion plant that attracts that pest’s natural predators. Before your eyes, a completely different type of food web develops. Again, when you up diversity in your garden or growing system, then you also up the diversity of nature’s miniature denizens. 

Science shows that a good deal of them can be good for your garden, too, by how they keep the pests you fear away – and without all those chemicals.


Plants of different kinds do another miraculous thing: they have an effect on the tiny life in the surrounding soil, air, and water that our naked eyes cannot see. This includes the bacteria, fungi, viruses, nematodes, and more that over time inflict diseases and poor health on the plants we all enjoy growing. 

While some plants may hopelessly attract one kind of disease, other plants could have a knack at repelling that same illness. Now, imagine if you put those two plants together. What a wonderful, natural way to balance and protect against plant diseases!


Different interplanted species can also help one another with weed prevention. Planting low-growing plants at the base of tall ones (lettuce at the base of broccoli plants, for example) can create a natural mulch that prevents any pesky weed seeds from sprouting and making it through. In the long run, this can save farmers both time AND money.


Similar to the above benefits, some low-growing plants may also thrive from the shade of taller plants they are planted next to. With companion planting and shading patterns in mind, you may be able to push the seasonality of some produce beyond its usual parameters. Grow spinach or other greens at the base of runner beans or corn, for example, and the shade cast from these taller plants may help curb the sun-stress they would experience during hotter times of year.


Beyond the perks plants get with pests, diseases, shading, and more, did you know that companions can even lean on each other for physical support? Take vining plants, for example. Plant them at the base of more towering crops – such as okra, corn, or even sorghum – and your garden can provide a form of natural trellising that saves you some real work!


Did you know that when you plant certain plants of one type with another, you can improve the flavors of your bounty? Many growers know that basil can enhance the tastes of garden favorites like tomatoes and peppers, as well as many other veggies. According to Natural Living Ideas, there are tons of additional flavor combos: celery can enhance broccoli, chamomile improves cabbage, and so on and so forth.


It’s the overall benefit of companion planting in general: if you come up with a harmonious planting plan, you will ultimately minimize the competition your crops face! Reduce weeds, pests, structural issues, and soil diseases, and you have less obstacles for your plants. This will allow them to do what they do best (and what you want them to do): grow to amazing sizes and qualities, completely uninterrupted and in peace


Another big picture perk you get out of companion planting? Ultimately, it’s a gentle way of growing, taking advantage of the amazing abilities nature has to offer. What companion plants do for one another helps growers skip out on the use of potentially harmful chemicals: whether they be pesticides, herbicides, or fertilizers – plus, less use of these expensive amendments may  also save growers a buck or two.


Monocultural practices give farmers a leading edge in some ways, including the large boost of quantity you get from a single crop in a specified space. However, growers who adopt companion planting cultivate a wider diversity of crops, making more options available to their markets (or just their home use as a hobby grower, if they so choose). With the benefits of a well-planned companion system, however, it’s arguable that the quality is loads better too.


Companion planting has plenty of incentives, as you can see. But why pursue this method in a greenhouse, of all places?


Simply put (and as you very well may know already), greenhouses create intense little microclimates for your plants that give them amazing advantages. A plastic-covered area heightens the effects of sunlight, humidity, and even moisture, at the control and discretion of the greenhouse grower, and for the favor of what they grow. 

Now: think of how living things (like bugs, spiders, grasshoppers, and more) will also respond – or even be attracted – to such environments! In truth, greenhouses can make it incredibly easy for certain pests to thrive; and due to their covered nature, it’s hard to get rid of them, or even get them to naturally escape. 

This is why good greenhouse management involving some companion planting is especially helpful. With a harmonious interplanting of botanical species, you’ll be able to attract a larger diversity of insects and life within your enclosed structure – versus an enormous, overwhelming population of one negative pest species.


In extension, companion planting may be beneficial for greenhouses because it can be part of a larger crop rotation. Monoculture (or “monocropping”) doesn’t just encourage the same species of pest to be trapped in your greenhouse environment again and again (since you continue to grow that same single plant they love). It also fosters the same soil diseases year after year, drawn to your plants and thus practically becoming an inherent part of your soil (especially if you don’t container plant).

Combining companionship with crop rotation – that is, changing what type of plant you sow in one place, from month to month, season to season, and year to year – is one of the best methods to prevent this from happening. It will ensure that your greenhouse environment stays healthy and balanced for any plants you choose to grow within, and help with soil building, conditioning, and diversity for those working to get the earth beneath their structures to be more viable.


You know all the benefits and perks of companion planting, and within a greenhouse as well. So what are some examples of great companions?


Just as they pair beautifully on the table, so do they pair in the garden. Basil is an aromatic herb known by many gardeners to enhance the flavors of tomatoes (and peppers, too). Not only that, they help keep certain pests away that love tomatoes: including fleas, flies, hornworms, and aphids.


Bright orange annual flowers with sunny dispositions, marigolds also do an interesting thing to the soil: they release a chemical that confuses and repels nematodes. Nematodes are microscopic, worm-like soil creatures that enjoy munching away at tomato roots. Plant marigolds at their base, however, and you’ll send these littler guys running for the hills.


Ever had to handle cabbage loopers? They’re cute caterpillars, but devastating to your brassica family of vegetables (which include cabbage, kale, kohlrabi, radishes, turnips, mustard, broccoli, and many other crops). In the height of summer, you’re bound to notice that flock of bright white butterflies descending on your brassicas to make their homes, hatch their young, and then munch away. 

But there’s one herb that butterflies won’t want to hang around: sage. If you strategically plant sage bushes around your precious broccoli or cabbage, these can help get rid of these pests, and keep your crops hole-free.


This trio of veggies may possibly be one of the oldest examples of vegetable companion planting in the world, having first been utilized by the Iroquois and other First Nation peoples thousands of years ago in North America. Each plant provides benefits for the other two in certain ways: corn gives a natural trellis for the climbing peas, the beans provide nitrogen for the squash and corn, while the squash covers the soil around the bases of the corn and beans, acting as a living mulch. 

In addition, the prickly and dense nature of the squash help keep some of the bigger pests away that love to munch on corn especially (think deer and raccoons).


They’re tasty together in a salad, but they’re even better when they grow together. There are a couple ideas around the companionship between this fruit and this green: spinach produces saponins in the soil around where it grows, which may encourage some soil-bound pests to keep their distance. It is also thought that the bushy nature of spinach blocks the view of strawberries from potentially hungry pests, particularly birds.


We all know horseradish as an incredibly hot, spicy food. Apparently, the root uses these same properties as a natural pest repellent when it is alive. In the soil and surrounding areas, its antimicrobially pungent oils keep away even the most tenacious of insects and bugs. 

This makes it an excellent companion for potatoes, since these tubers can be at the mercy of many subterranean worm species that enjoy munching away at your cash crop. Just make sure you control your horseradishes, because they do love to spread!


A growing combination of cucumbers and sunflowers is another popular favorite. Plant sunflowers just a little earlier, and then surround them with your planted cucumber seed mounds just a week or two later. As these spindly flowers tower over the mounds, the cucumbers will grow up their stems, providing a natural trellis while making these tasty squashes easier to harvest.


Okra and peas also make a great match, in the similar tradition of cucumbers and sunflowers. As okra grows taller, peas can use their stalks as a sturdy trellis. This will boost their production and make peas easier to harvest. 

Even better, planting peas on the north side of an okra row when the season warms up can make okra cast some much needed shade on this cool weather crop. With companion planting here, you can create some natural season extension!


As you put together your greenhouse plan, keep in mind that companion planting is not just a gardener’s fancy: it’s also an amazing tool for the cleverest farmers. Greenhouse environments create attractive, favorable environments for your plants, but also for the soil diseases and pests that love to consume them! 

To keep them at bay, foster healthy relationships between a larger diversity of plants. It will be better for your business (or hobby), and potentially even better for your pocket and the environment.

Lucija Johum 20 December, 2021
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