The Truth About Companion Planting: What Works & What Doesn’t
If you’ve spent any time researching gardening on social media, you’ve probably seen those colorful companion planting charts promising bigger harvests and fewer pests—just by planting the “right” crops together. That may have led you to wonder – does companion planting TRULY work?
But here’s the truth:
Some companion planting methods work really well… some barely make a difference… and a few can actually cause problems.
I started gardening over 13 years ago with some plants in my backyard. I had no idea what I was doing besides tossing some plants I purchased at the store into the ground and hoping for the best.
Over the years, I tried so many different suggested companion plant pairings. Any gardener wants their plants to thrive, so it’s natural to want to give anything a try that may lead to a larger yield and reduced pests.
Pests really are the bane of our existence as gardeners!
So, we’re going to cut through the noise and focus on what actually works in a real backyard garden—so you can grow healthier plants without wasting time or space. I’ve wasted enough of both for all of us.
Related: 10 Beautiful Flowers to Plant with Vegetables in Your Garden
What is Companion Planting?
Companion planting is the practice of growing certain plants together to benefit one or both crops. The idea is that some plants act as buddies, enhancing some or potentially driving away pests.
Gardeners typically use it to:
- Reduce pests
- Improve plant growth
- Attract pollinators and beneficial insects
- Make better use of their limited space
It’s a helpful tool—but it’s not magic. Think of it as one piece of a bigger puzzle that includes healthy soil, proper spacing, and good watering habits. Just because you grow marigolds near your tomato plants does NOT immediately mean everything will turn out wonderful.
The real truth about gardening is that you can do all the “right” things and still not have a great growing year.
Why Companion Planting Works (Sometimes)
Many times, this practice only works SOMETIMES for me. When companion planting does work, it’s usually because of a few simple natural principles:
1. Biodiversity Confuses Pests
Large areas of a single crop attract pests quickly. Mixing plants makes it harder for insects to find what they’re looking for. Monoculture planting works in large farms because they tend to spray more pesticides, but a small gardener can reap the benefits of biodiversity in their backyard garden.
2. Strong Scents Can Mask Crops
Plants like onions, garlic, and herbs can help disguise nearby vegetables from pests. Some plants have stronger scents than others, masking the smell of the plant they really want to find.
3. Some Plants Attract Beneficial Insects
Flowers like dill and alyssum bring in predators like ladybugs and parasitic wasps that feed on garden pests. Many plants also rely on pollinators for a harvest. If you attract a variety of pollinators to your garden, that improves the odds of having a wonderful harvest of zucchini, cucumbers, and other crops.
4. Trap Crops Pull Pests Away
Certain plants (like nasturtiums) attract pests away from your main crops. The pests leave the plants you want to harvest alone in exchange for a sacrifice of another plant.
That said, many popular companion planting claims haven’t been scientifically proven, and results can vary depending on your location.
Related: How to Get Rid of Tomato Hornworms: 12 Tricks That Work
Companion Planting Pairs That Actually Work
Ok, now the good stuff – what companion planting pairs ACTUALLY work in the average backyard garden?
Related: 13 Companion Planting Combinations That Actually Work
1. Pest-Repelling Pairings
These combinations can help reduce pest pressure (not eliminate it):
- Tomatoes + Basil
Basil may help deter some pests and is easy to tuck between plants. - Carrots + Onions
Onion scent can help confuse carrot flies. - Cabbage + Dill
Dill attracts beneficial insects that prey on cabbage worms. - Squash + Nasturtiums
Nasturtiums act as a trap crop for aphids and squash bugs.
I think it’s really important to stress that, by planting these pairs together, you are NOT guaranteed to have NO pests in your garden. Instead, you should have FEWER. Tomatoes and basil together work great (I mean, they’re delicious together too!), but it isn’t magic.
I often keep basil on the edges of my tomato beds; it seems to work to reduce the pests I see on my plants. Nasturtiums grow well around the edges of raised beds as well!
2. Plants That Attract Beneficial Insects
This is one of the most reliable companion planting strategies.
Add these throughout your garden:
- Alyssum – attracts hoverflies (aphid predators)
- Dill – attracts parasitic wasps
- Calendula – draws pollinators and helpful insects
- Marigolds – may help with soil nematodes (varies by type)
With these plants, I highly suggest scattering them throughout your garden beds. The more you have (in general), the more beneficial insects you can attract. Plus, calendula has medicinal benefits you can reap later when harvesting the plants.
3. Space-Saving Combinations (Highly Effective)
This is one of the most overlooked benefits of companion planting. If you don’t have a large garden space, combining these companion planting pairs will help your garden grow more food (that’s the goal) without needing to add more pots or raised beds.
- Tomatoes + Lettuce
Lettuce benefits from shade under tomato plants. - Corn + Beans + Squash (Three Sisters)
- Corn = support
- Beans = nitrogen
- Squash = ground cover
- Carrots + Radishes
Radishes grow quickly and loosen the soil for slower carrots.
This form of companion planting works because you’re maximizing the sunlight, soil depth, and your space. Growing carrots and radishes has always been a favorite for me. Radishes sprout quite fast, but carrots take time. Try growing a row of radishes, then a row of carrots, etc. You’ll easily be able to spot where your rows of carrots are.
The Three Sisters method is one of the most well-researched trios of plants. We know Native Americans used this trifecta to plant their crops, and if it works for them, we can surely use their wisdom to grow food in our backyard today.
4. Soil-Improving Pairings
One of the most overlooked benefits of companion planting isn’t pest control—it’s improving your soil naturally while your garden is growing. Some plants ADD nutrients back into the soil, and when you plant these next to a plant that needs more of that particular nutrient, it’s a pairing meant to be.
- Beans & Peas with Heavy Feeders
These legumes help add nitrogen to the soil. Legumes like beans and peas have a unique ability: they work with beneficial bacteria in the soil to pull nitrogen from the air and convert it into a form plants can use. - Deep-Rooted Plants (Advanced Tip)
Some plants have deep root systems that mine nutrients from lower soil layers and bring them closer to the surface. Examples of these plants include comfrey, borage, and dandelion. You can plant these crops along the edges of raised beds or use them chopped as mulch.
Some examples of heavy feeders include corn and squash! Try growing beans and corn together or beans and squash.
Companion Planting Pairs That DO NOT Work
Now, let’s go to the opposite side – the companion planting pairs that don’t work. This is where a lot of gardening advice goes wrong, and you’ll see A LOT of overhyped suggestions with little evidence to support their claims.
Some overhyped companion planting pairs include:
- “Marigolds repel all pests.” → Not true
- “Basil makes tomatoes taste better” → No solid evidence
Is there anything wrong with planting marigolds in your garden beds? Absolutely not! I plant them because they DO repel pests, but once again, it’s not a magic wand that will eliminate all pests in your garden. However, the pop of color is my favorite part.
Planting Combinations You Should Avoid
Some plants simply don’t grow well together:
- Beans + Onions or Garlic
These can stunt bean growth. - Tomatoes + Corn
They attract the same pests. - Potatoes + Tomatoes
Both are prone to blight—planting together increases risk.
Try to remember that plants in the same family often attract the same pests and diseases. Planting them together increases the risk of pests coming in and wreaking havoc in your garden!
How to Make Companion Planting Work in Your Garden
It’s a great idea to give companion planting a try in your garden, but don’t get overwhelmed! You don’t have to try every combination immediately. Here are some tips to make this garden trick work for you.
- Pick a Main Crop. Start with a main crop in your garden, such as tomatoes or peppers. You don’t need to find companions for ALL your garden plants.
- Add a Helpful Companion. Now, pick one or two companion plants to add alongside your main crop. For example, I always grow basil with my tomato plants.
- Avoid Overcrowding. One of the problems with companion planting is that gardeners tend to get excited and plant TOO much in one area. Overcrowding is a real issue in a vegetable garden. It will cause increased diseases, reduced airflow, and smaller harvests.
- Take Notes. Watch how your garden does, especially the main crops. Did you see a noticeable difference? Record what you learn and adapt for the following year. Next year, you may try another combination!
Perhaps what I want you to understand the most is that this is not magic. Using the companion planting method CAN work, but not every combination you see online is the answer. You should start simple and pay attention to what works, adjusting each season.
