When I first dipped my toes into gardening, cucumbers were the stars of my veggie dreams. But like most beginners, I learned the hard way—there’s more to a thriving garden than just sunshine and water.
My first cukes came out small, sad, and far from salad-worthy. I followed every rule in the book, so the real troublemakers had to be the plants growing nearby. And trust me, they were not good neighbors.
These greedy companions hogged all the nutrients, elbowed in on space, and even rolled out the red carpet for pests.
Turns out, not every plant plays nice in the garden patch.
If your cucumbers are struggling too, these bad buddies might be to blame. Let’s take a look at the worst offenders…
1. Mint, A Lovely Herb That Can Take Over Your Garden
We all love mint, but there’s a huge downside to it – it loves to spread out and take over your garden!
With these types of plants, it’s best to keep them in pots and planted away from cucumbers. If you plant it in the garden, mint will take up all the space and nutrients, leaving little for your cukes to thrive.
Learn from my mistakes and give mint its own spot so it doesn’t crowd out the cucumbers!
2. Sunflowers Can Only Slow Down Your Cukes
It’s hard to believe that cheery sunflowers could have a dark side, but it’s true! They release natural compounds that can slow down the growth of nearby plants, especially cucumbers.
They cast such a heavy shade that your cukes can barely get any sunlight. Poor nutrient and sunlight availability can significantly cut down on their harvest (you won’t even get to pickle one jar of cucumbers).
So, to keep both plants happy, I would recommend you give sunflowers and cucumbers their own separate places in the garden.
Related: Here Are The Best And Worst Plants To Grow Near Your Sunflowers
3. Fennel Ruins Your Cucumbers By Releasing Chemicals In The Soil
I know fennel can be delicious, but if you’re thinking about adding it to your garden, keep in mind that it releases chemicals that tend to slow down neighboring plants (including our beloved cucumbers).
Cukes planted close to fennel won’t grow as well, with smaller harvests and lower-quality fruit. This tasty plant also attracts pests like aphids and caterpillars, which could do extra harm to your cucumbers.
If you were to grow both of them in the garden, make sure there’s some distance between the two!
4. Squash And Cucumbers Are Relatives That Don’t Get Along
Planting squash too close to cucumbers can invite a whole crowd of pests to the scene.
That’s because squash and cucumbers are in the same plant family, so they share pests like powdery mildew and squash vine borers. One annoying critter (the pickleworm) will even go after both squash and cucumber fruits.
To keep your cucumbers safe, it’s best to give these family members a little space.
5. Melons Attract Pests That Can Harm Your Cukes As Well
Same family alert!
Watermelon, cantaloupe, and honeydew are cousins to cucumbers in the Cucurbitaceae family, meaning they attract the same pests and diseases, such as cucumber beetles and powdery mildew.
Growing them together can mean more bugs and disease spreading around, which often leads to lower yields and poorer fruit quality.
Keeping these plants separated can help reduce the risk of cross-infection and keep your harvest healthier.
Related: Cucumber Leaves Turning Yellow? 5 Causes And Their Solutions
6. Zucchini And Cucumbers Need Similar Care But Aren’t Exactly The Best Neighbors
Even though cucumbers and zucchini come from the same family and share growing needs (plenty of sunlight, well-drained soil, and lots of water), they still aren’t the best garden neighbors.
Since they attract the same pests and diseases, like gray mold, mildew, and cucumber mosaic virus, planting them side by side can make these issues even worse.
Some distance between them helps reduce the spread and keeps both plants in top shape!
Related: Save Your Zucchinis From 5 Awful Pests With These Simple Tricks
7. Sage Won’t Cleanse Or Heal Your Cucumbers
Sage isn’t exactly the best buddy for cucumbers in the garden.
For one, its strong aroma can mess with that fresh cucumber flavor we all love. They’ll also end up competing for water, which can leave cucumbers thirsty and possibly stunting their growth.
It would probably be a good idea to keep sage and other herbs away from your cukes (I usually grow mine in pots!).
Related: Popular Herbs You Shouldn’t Grow Near Cucumbers
8. Potatoes Are Big Feeders That Can Take Up All The Nutrients
Even though potatoes grow underground, they are still not good companions to cucumbers.
That’s because they’re both susceptible to blight, which can take out both plants if it spreads. And they’re both big feeders, so they’ll end up fighting over nutrients – potatoes usually take the upper hand with their deep roots, leaving cucumbers a bit deprived.
So, plant one or the other if you have a small garden. But if you have enough garden space, I’m sure you’ll find room for both of these plants!
Just remember, if you want your cucumbers to thrive, it’s important how you grow them and where you grow them. Not all plants are allies, so pick and choose wisely!
9. Peppers Might Be Too Hot For Your Cucumbers To Handle
I love growing peppers, but I’ve learned the hard way that they don’t always play nice with cucumbers. At first, I thought they’d make great companions—after all, they both love warm weather and plenty of sunlight. But nope!
Peppers and cucumbers have different watering needs, and cucumbers love moisture way more than peppers do. When I planted them together, my peppers weren’t happy with all that extra watering, and my cukes didn’t appreciate the drier soil that peppers prefer.
Not to mention, they both attract aphids, which made my garden feel like a free buffet for these tiny pests. So, while peppers and cucumbers are delicious, I now keep them separate to avoid the struggle.
10. Corn Might Steal The Show (And The Resources)
Corn is such a summer garden staple, and I totally get why people want to grow it. I tried planting it near my cucumbers once, thinking it would provide some nice shade during the hottest part of the day. Big mistake!
Corn is a heavy feeder, which means it takes up a ton of nutrients from the soil—nutrients that my cucumbers desperately needed. The result? My cucumbers were struggling while my corn was thriving.
On top of that, corn attracts pests like corn earworms and aphids, which, you guessed it, also love cucumbers! Since that failed experiment, I’ve made sure to give my corn and cucumbers their own separate spaces so they can both grow happily.
Related: Find Out If Cucumbers Are Friendly To Each Other And How Far Apart They Should Be Planted
11. Broccoli Brings In Bugs And Competes For Resources
Broccoli might seem like a healthy and harmless veggie to grow, but it turns out it’s not a great neighbor for cucumbers.
Both of these plants are heavy feeders, which means they’ll be constantly fighting over nutrients in the soil. On top of that, broccoli can attract cabbage worms and flea beetles—pests that don’t mind making a pit stop on your cucumbers too.
Trust me, it’s better to plant broccoli away from your cukes so neither of them has to compete or suffer from unwanted bugs.
12. Rosemary Is A Pest Magnet In Disguise
While rosemary is a fragrant and hardy herb, it’s not exactly the kind of plant you want too close to your cucumbers.
It tends to attract spider mites and whiteflies, which love to feast on tender cucumber leaves. Plus, rosemary prefers drier conditions and doesn’t like the consistently moist soil that cucumbers crave—meaning one plant will always be left unhappy.
For a smoother gardening experience, give rosemary its own sunny, well-drained spot far away from your cucumbers.
13. Basil Might Be Great In Salads, But Not Beside Cucumbers
Basil is a kitchen favorite, but it’s not a match made in garden heaven for cucumbers.
While basil does help repel some pests, it thrives in drier conditions and well-drained soil—exactly the opposite of what cucumbers prefer. When planted nearby, either your cukes stay too dry or your basil stays too soggy. Nobody wins.
Plus, basil’s strong aroma and essential oils can interfere with cucumber pollination and flavor development (yes, even subtle scent interactions can matter!). So, plant your basil closer to tomatoes or peppers, where it’ll be happier and more helpful.
14. Garlic Might Ward Off Vampires—And Your Cucumber’s Growth
Garlic is a powerful pest deterrent and a staple in many gardens, but it doesn’t pair well with cucumbers.
Why? Garlic and other alliums (like onions and shallots) release compounds into the soil that can inhibit the growth of nearby plants—especially cucumbers, which are more sensitive to these chemical interactions.
They also compete for nutrients and can make the soil less hospitable for moisture-loving cukes. For best results, give garlic its own bed away from your cucumber patch and enjoy both harvests without the silent struggle underground.