Companion Planting 101 (w/ Garden Companion Planting Chart)

Companion planting is a funny thing. Some gardeners swear by it, while others say it is nothing but a bunch of baloney. And then trying to remember what planting combinations are suggested, or which are frowned upon? Talk about confusing! So, let’s explore the world of companion planting. This article will discuss the general concept, how important (or not) companion planting really is, tips to get started, and some of the real benefits of companion planting – such as attracting pollinators. I’ll also share our handy companion planting chart as an easy reference guide at the end.

What is Companion Planting?

In the most general terms, companion planting is the idea that some plants thoroughly enjoy growing near one another. Meanwhile, others would prefer not to. Thankfully, as you’ll see in the companion planting chart at the end of this article, there are far more plants that get along than those that don’t. The University of Massachusetts Center for Agriculture further explains: 

“Companion planting is growing two (or more) crops near each other with the theory that they help each other in nutrient uptake, improved pest management and reduced pesticide use, enhanced pollination and higher vegetable yields.” 

Beneficial Companions

A recommended companion planting combination usually provides some sort of benefit to one (or both) of the plants, or brings an added perk to your garden in general. I call these “good friends” in our companion planting chart. Some may have a profound relationship, relying on each others natural plant hormones to promote growth or protection. Other relationships may be as simple as one providing shade for the other.

Take the classic Native American “Three Sisters” companion planting combination of corn, squash and beans for example. It is perfect for maximizing yield in compact spaces. The corn grows tall and thin, leaving open space for sprawling squash plants below. They shade the soil and help it retain moisture. Pole beans add nitrogen to the soil (which feeds both the squash and corn) and can utilize the corn as a support trellis to climb.

Incompatible Plants

On the other hand, some plants are often recommended to not plant directly next to certain others – their known or suspected “foes” as I call them in our companion planting chart. Those combinations may cause each other issues, such as stunted growth.

A common no-no combination in the companion planting world is growing peas in close proximity to onions or garlic. Why? Well, there honestly isn’t much scientific evidence to support it, even though you’ll see this suggestion time and time again. A few theories are because garlic and onions are “heavy feeders” while peas are not. This makes their fertilizing needs incompatible. Peas also add nitrogen to the soil, while onions and garlic don’t like too much. Another idea is that the pea’s sensitive shallow root system may be disrupted by the growth or harvest of onions and garlic nearby. 

How Important or Scientific is Companion Planting?

Just like the pea and onion example above, much of companion planting “proof” is mostly based on theory or anecdotal evidence. This is especially true when it comes to the supposed incompatible plants. I’ve tried to research scholarly articles that back companion planting with science, and let’s just say they’re lacking. That doesn’t necessarily mean it’s all bunk though! Experimentation and personal observation is how all scientific theories get started, after all. If many gardeners have seen the results of companion planting in their own garden, I say it is worth considering. 

My thoughts and experience: 

Companion planting must have some truth behind it, or it wouldn’t be such a popular subject in the gardening world. However, I pay most attention to the beneficial planting combinations (described more below). Those make clear sense to me! When possible, I try to avoid the frowned-upon combinations too – but with less scrutiny.

I like to think of the “no-no” planting combos like neighbors. We don’t adore all of them, right? We all have different needs, lifestyles, and tolerance for nuisance. But will I up and die if I have to live in close proximity to someone I don’t particularly care for? No, probably not. I will chug along and live my life, perhaps just a little less happily…

For instance, we have inter-planted beans with peppers in the past, as well as garlic near peas – both supposed incompatible foes. They still grew, though I do admit they seemed less healthy and vigorous than usual. Perhaps it was just an off year? Or maybe it was the nuisance neighbor.

In all, I try to set my plants up to live their best life, with as few hindrances as possible. My suggestion is to make a modest effort to follow the “rules” of companion planting. Yet if limited space or other circumstances leads you to break the rules – don’t stress about it too much!

 BENEFITS OF COMPANION PLANTING

Companion Plants Attract Pollinators & Beneficial Insects

Pairing fruit or vegetable plants with flowers like calendula or borage is the perfect way to attract pollinators such as bees and butterflies to your garden. Some vegetables like tomatoes, green beans, peppers, and peas are considered self-fertile. That means they do not require the action of a pollinator to develop fruit. In contrast, many other crops like squash, cucumber, melons, okra, and many berries and fruit trees rely on pollinators to produce.

Fruit or no fruit, I always encourage planting for pollinators! They need all the help they can get. Check out our list of Top 7 Easy Annual Companion Flowers to grow from seed. In that article, I dive deeper into the unique benefits and uses of each flower. Or see our overall favorite Top 23 Plants for Pollinators for more ideas. 

Bees and butterflies aren’t the only good guys we want to encourage in our gardens though. Companion planting with herbs like basil, fennel, cilantro, sage and dill will create habitat, food, or otherwise attract other small beneficial insects like lacewings, parasitic wasps, hover flies, predatory mites, or ladybugs. Those guys all play an important role in natural pest control.

Companion Planting for Pest Control

Predatory insects

Companion planting can help reduce pest issues in a number of ways. As we already explored, some companion plants attract beneficial insects – and some of those are predatory in nature! Our little ladybug and lacewing buddies ferociously feed on aphids, mealybugs, and other soft-bodied pest insects. Parasitic wasps help keep pest caterpillar populations down by laying their eggs and larvae on them. Spiders and praying mantis also feed on pest insects, though they don’t discriminate against the beneficial ones either.

Trap Crops

Other companion plants DO attract pest insects – but distract the pests away from your fruit and vegetables plants instead! These are referred to as “trap crops”, or sacrificial crops. Nasturtium is a prime example of a trap crop. Nasturtium attracts both aphids and cabbage worms, while the nearby plants are often spared. When trap crop plants become heavily infested they should be removed from the garden. Nasturtiums also provide pollen and nectar, making them a favorite for bees and hummingbirds. 

Pest Deterrents

A third way that companion plants deter pests is through their unique biology. Some plants have characteristics or substances that are either undesirable or detrimental to select garden pests.

For example, hot pepper plants contain a substance within their root system that is effective at warding off and preventing root rot diseases, such as Fusarium rot. This helps keep root rot away from other companions in the same planting bed. Additionally, basil and other other fragrant herbs like dill, chives, and cilantro help to repel aphids. The sharp smell of marigold flowers also reportedly keeps pest insects away.

A note about marigolds and root-knot nematodes

French marigolds are possibly one of the most famous companion plants. That is because the roots of French marigolds contain a natural nematocide that kills root-knot nematodes. Root-knot nematodes are a microscopic and harmful nematode that feed on root systems, reducing plant health and yields.

This makes marigolds an excellent companion to plant with tomatoes, squash, melon, and other crops frequently affected by root-knot nematodes. Furthermore, this particular companion planting benefit IS scientifically backed! Yet it is often misunderstood by the well-intended gardener. See, planting one little marigold plant next to a tomato may not be all that effective…

In order to reap the benefits of French marigold companion planting, the marigold root system must be left in place. This means cutting the marigold plant out at the soil line (no-till style) rather than pulling it out at the end of the season. Even better results are achieved if many marigold plants are grown prior to planting the veggie crop in the same location. Root knot nematodes aside, marigolds are attractive to beneficial insects and bring a beautiful pop of color to the garden!

Companion Planting for General Garden Health

Variety is the spice of life! Beyond the benefits of companion planting we’ve already discussed, variety is generally desirable in a garden. Each unique plant can fill a niche and add value. Some are edible. Others attract or deter insects. Many are medicinal (probably more than you realize)! Cover crops like fava beans are edible too, but also naturally enrich soil with their ability to fix nitrogen in their roots. Not to mention, many companion plants are absolutely beautiful!

Companion planting is a form of polyculture, or planting several types of crops together in a small space. Polyculture and companion planting help increase the biodiversity in your garden – an esteemed achievement in organic gardening. When you compare a thriving biodiverse garden (a mini-ecosystem) to traditional agriculture, the small diverse garden is less likely to be overrun with disease or pests. It reduces the need for pesticides or other chemical products. Diverse gardens also have more robust immune systems to handle environmental stress such as drought, heat, or cold snaps.

Tips to Get Started with Companion Planting

• Some of the best and easiest companion plants to grow amongst your vegetables are flowers and herbs. Calendula, nasturtiums, basil, cilantro, oregano, parsley, thyme, and rosemary all have no known “foes” – so feel free to tuck them in where ever you can! Calendula is my all-time favorite companion plant, flower, and medicinal herb, so you’ll find it in almost every one of our garden beds. Learn more about how to grow, harvest, and use calendula here.
  
  
• When you are planting many things in one space, do remember to practice good plant spacing – companions included. I know… this is easier said than done! I need to try to heed my own advice. Because over-crowding plants can thwart the benefits you’re trying to gain with companion planting in the first place! Crowded plants compete for nutrients, water, sunlight and air flow. They’re more prone to disease like mildew and blight. Pests and disease also more easily pass between them. The good new is: most companion flowers and herbs take kindly to pruning, so feel free to cut them back as needed to give your veggies the space they need.
  
  
• Make a plan. Rather than heading outside with a bunch of seedlings and stuffing them in a bed willy-nilly, sketch out a plot plan of where you want to plant them first. That way, you can reference your companion planting chart as you go. You’ll be less likely to run out of room and – Oops! have to plant two foes next to each other. Of course, it doesn’t need to be set in stone, but making a plan definitely helps me stay more organized.
  
  

Companion Planting Chart

And now… what you likely came here for! Please enjoy this companion planting chart that I put together, just for you. I gleaned and complied information from dozens of different gardening books and online resources to create one comprehensive guide.

Truth be told, I actually made this as part of the 20-page Homestead and Chill subscriber Garden Planning Toolkit! In addition to the companion planting chart, the toolkit includes a garden journal, plot plan template, planting calendars, and more. The planting calendars show when to start seed indoors, transplant outdoors, or sow seeds directly outside – for every USDA hardiness zone 2 through 12! Enter your email below if you’d like to receive a copy.

Alright, back the chart. I realize the font is small. Sorry! It was tough fitting everyone on one page. If it is too difficult to view here on the blog, simply click download below for a printable PDF version. We keep a copy of the companion planting chart on the fridge, along with our zone planting calendar.

And that is the low-down on companion planting.

Have you experimented with companion planting yet? What are your thoughts? Do you think it works, or is the jury still out? As far as I am concerned, there is no harm in trying. Plus, the more flowers and herbs, the better! Please feel free to ask questions, leave feedback, or share this article. Happy (companion) planting!

Other organic gardening articles you may enjoy:

• Seed Starting 101: How to Sow Seeds Indoors
• How to Amend & Fertilize a No-Till Garden Bed Between Seasons
• Composting 101: What, Why & How to Compost at Home
• Organic Pest Control: Over 25 Ways to Stop Pests from Destroying Your Garden
• How to Design & Build a Raised Garden Bed