Companion planting for onion is an experience-based observation developed over centuries. People have noticed that planting certain plants side by side has a positive effect on each other, increasing the quality and quantity of the harvest.
Companion planting is not set in stone and it is the least you can do for your plants. You can get the right care from the individual plant article. You can see the companion and the enemy plants of onion below.
Companion plants for onion | Enemy plants of onion |
---|---|
Chamomile | Beans |
Beetroot | Asparagus |
Strawberry | Common sage |
Tomato | Garlic |
Pepper | Chives |
Mint |
Why does companion planting work?
Companion planting works due to several interconnected factors:
Pest Control: Certain plants emit natural chemicals or scents that repel pests, effectively acting as natural pest deterrents for nearby plants. This reduces the need for chemical pesticides and fosters a more balanced ecosystem.
Attracting Beneficial Insects: Some companion plants attract beneficial insects like ladybugs, hoverflies, and predatory wasps, which feed on common garden pests. This creates a natural form of pest control and helps maintain ecological balance.
Soil Improvement: Different plants have varying root structures and nutrient requirements. Companion planting can enhance soil health by reducing soil erosion, suppressing weeds, and improving nutrient uptake. For example, leguminous plants fix nitrogen in the soil, benefiting neighboring plants that require nitrogen for growth.
Competition Reduction: Companion planting can help reduce competition for resources such as water, sunlight, and nutrients by utilizing plants with complementary growth patterns and root structures. This allows for more efficient resource utilization and healthier plant growth.
Biodiversity and Resilience: Planting diverse species together increases biodiversity in the garden, which can enhance ecosystem resilience. A diverse ecosystem is better equipped to withstand pests, diseases, and environmental stresses compared to monocultures.
Maximizing Space: Companion planting allows gardeners to make the most of limited space by intercropping plants with different growth habits and maturity rates. This maximizes yield per square foot and promotes efficient land use.
Overall, companion planting capitalizes on the natural synergies between plant species, creating a thriving and sustainable garden ecosystem.
What are the companion plants of onion?
The following plants have positive effects on the growth of your onion. These plants can repel pests that damage your plants. These plants provide increased nutrition to the soil that your plants can use. Therefore, we recommend planting these plants next to your onion.

Chamomile
Chamomile thrives in diverse growing conditions. Flourishing in well-drained, loamy soil under gentle sunlight, it embodies adaptability and calmness. Consistent moisture and occasional pruning support lush growth and abundant flowering. Chamomile offers general benefits to neighboring plants by attracting beneficial insects, such as pollinators, and enhancing overall biodiversity.
Chamomile isn’t just a pretty flower; it actually helps onions grow stronger and taste better! This fragrant herb improves the soil around onions and attracts helpful pollinators, making sure your onions develop into big, flavorful bulbs.



Beetroot
Beetroots, celebrated for their earthy sweetness and nutrient-rich composition, thrive amidst fertile soil and ample sunlight. They prefer well-drained earth with a pH range of 6.0 to 7.0, ensuring optimal growth and development. Regular watering and loose soil encourage healthy root formation and vibrant foliage.
Beets and onions make great garden buddies because they don’t compete for space. While onions grow tall and slender above ground, beets form their tasty roots below, making the most of every inch of soil without getting in each other’s way.



Strawberry
Strawberries grow in loamy soil with a pH range between 5.5 and 6.5. Full sunlight and consistent moisture nurture their delicate fruits and lush foliage. Strawberries provide invaluable benefits to neighboring plants by attracting pollinators, suppressing weed growth with their dense foliage.
Strawberries love to spread out, creating a protective ground cover that helps keep weeds away from onions. Plus, onions’ strong scent confuses pests that would otherwise nibble on strawberry plants, keeping them safe and thriving.



Tomato
Tomatoes thrive in various soil conditions. Flourishing fertile soil with a pH range between 6.0 and 7.0. Full sunlight and consistent moisture nurture their sprawling vines and abundant fruiting. Tomatoes provide invaluable benefits to neighboring plants by attracting pollinators, suppressing weed growth with their dense foliage, and adding richness to culinary dishes.
Tomatoes can be a great companion for onions because they help enrich the soil with key nutrients. Since both plants thrive on nitrogen and phosphorus, using a tomato-friendly fertilizer can support strong onion growth. The nitrogen helps the onion plants develop lush green tops, while phosphorus encourages healthy bulb formation.



Pepper
Peppers expand in diverse soil conditions. Flourishing in well-drained, loamy soil with a pH range between 6.0 and 7.0. Full sunlight and consistent moisture nurture their vibrant foliage and prolific fruiting. Peppers provide invaluable benefits to neighboring plants by deterring pests with their pungent compounds, attracting pollinators, and adding diversity to the garden landscape.
Onions and peppers don’t compete for nutrients, making them perfect neighbors. While onions keep certain pests away, peppers thrive in the same soil conditions, growing alongside onions without causing any trouble.



Mint
Mint thrives in various soil conditions. Flourishing in well-drained, moist soil with a pH range between 6.0 and 7.0. Partial shade and consistent moisture nurture its lush foliage and aromatic leaves. Mint provides invaluable benefits to neighboring plants by repelling pests, attracting beneficial insects, and promoting a sense of freshness in the garden.
Mint is a great companion for onions because it naturally repels insects like aphids and onion flies. Its strong scent confuses pests, making it harder for them to find your onions. Just be sure to keep mint contained, or it might take over your garden!
What are the enemy plants of onion?
Planting these plants next to onion has a huge negative effect on the development of your plant. Growing enemy plants can appeal detrimental insects, change the taste of the grown plant and even consuming all of the nutrients and water from your onion. Because of these negative effects, we don’t recomment growing the plants below next to your onion.



Beans
Beans are thriving in well-drained soil and basking in ample sunlight, these leguminous wonders enrich the soil with nitrogen, enhancing the vitality of their botanical companions. As stalwart providers of sustenance and greenery, beans epitomize the essence of garden bounty and vitality.
Beans and onions just don’t see eye to eye. Onions release compounds into the soil that can slow down bean growth, while beans take up space and nutrients that onions need. It’s best to plant them far apart so both can do their thing without interference.



Asparagus
Asparagus, revered for its tender spears and nutritional prowess, stands as a stalwart sentinel in the realm of companion gardening. With a penchant for well-drained, sandy soil and ample sunlight, this perennial delight thrives in environments where winters are cold and summers are warm. As a symbol of grace and gastronomy, asparagus enriches both the palate and the garden landscape, embodying the essence of verdant vitality.
Asparagus plants are heavy feeders, and onions don’t like the competition. Since both plants need plenty of nutrients to grow well, keeping them together can leave your onions small and struggling. Give them separate spots in the garden for the best results.



Common sage
Common Sage grows in diverse soil conditions. Flourishing in well-drained, sandy or loamy soil. Full sunlight and moderate moisture nurture its aromatic foliage and sturdy growth. Common Sage provides invaluable benefits to neighboring plants by repelling pests, attracting beneficial insects, and adding culinary richness to the garden.
Sage is a wonderful herb, but it just doesn’t play nice with onions. This strong-scented plant prefers dry, well-drained soil, while onions like things a bit more moist. Their growing needs don’t match up, and when planted together, neither one thrives.



Garlic
Garlic flourishes in well-drained, fertile soil with a pH range between 6.0 and 7.5, it embodies adaptability and strength. Adequate sunlight and consistent moisture support robust growth and bulb development. Garlic provides invaluable benefits to neighboring plants by deterring pests with its strong aroma and acting as a natural fungicide against soil-borne diseases.
Onions and garlic may seem like a natural pair, but they’re actually too similar for their own good. Both are from the allium family and need the same nutrients, which means they’ll end up competing rather than helping each other grow.



Chives
Chives thrive in well-drained, fertile soil enriched with compost, they embody adaptability and finesse. Adequate moisture and sunlight support lush growth and abundant foliage. Chives extend general benefits to neighboring plants by repelling pests and attracting beneficial insects, enhancing overall garden biodiversity.
Chives and onions are closely related, but that’s exactly why they don’t make great neighbors. They take up similar resources and can lead to overcrowding, which stunts growth. Plus, planting them together can increase the risk of spreading diseases between them.