The Best Companion Plants for Leeks

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Leeks are an excellent addition to your garden. They are visually stunning, growing upright and perfect, adding texture and height to the garden. As a vegetable, they taste amazing, especially fresh from the garden. Growing them isn’t tricky either; they are generally fuss-free! But picking a few companion plants for leeks can help prevent pests and even make your leeks tastier.

Fresh raw leeks on white background.

The Benefits of Companion Planting

Companion planting brings a whole host of benefits to the organic home garden. All plants have beneficial partners who can help improve growth, taste, yield, and deal with pests and disease problems. Benefits of companion planting:

Attract pollinators: Plants with bright flowers colors and lots of pollen and nectar attract pollinators like bees. We all want extra pollinators in our gardens to increase our yields!

Attract beneficial predatory insects:  Many plants will attract helpful bugs like parasitic wasps and ladybugs to the garden to help eradicate insect pests.

Repel harmful insects: Some plants have intense scents that control common garden pests, like squash bugs, and tomato worms. Or they attract harmful pests and work as a trap crop to keep these pests away from your precious crops/

Help improve the soil: Some flowers like marigolds help destroy root-knot nematodes that live in the ground and destroy roots from below. While other plants like leafy greens can act as living mulch to help control moisture. In other instances, plants with large taproots like parsnips can help break up heavy soils.

Help control weeds: Densely underplanting with vegetables like spinach or with leafy trailing flowers like nasturtiums will help manage weeds.

Companion planting can help with disease issues. Diseases are spread more quickly through your garden when plants of the same type are grouped. Adding different species throughout the planting can help break up the garden and slow the spread of diseases like powdery mildew or blight.

Closeup into a french formal garden in autumn with Brussels sprouts, lettuces, leeks and pumpkins. The image is to illustrate the many companion plants for leeks.

Planting Tips For Leeks

Leeks are not hard to grow but need a long growing season. This means starting three months before the last frost date for zones with short seasons. You can also pick up starts at garden centers in the spring. I am always surprised more people don’t grow leeks in vegetable gardens!

Leeks are incredibly cold-hardy. If I can chip through the snow and ice to get at my leeks, I can harvest them in the middle of winter!

Seed Starting: Sow indoors in early spring and move to a protected cold frame if you have one.

Sun Requirements: Will do best in full sun but tolerate partial shade.

Soil requirements:  Requires rich, loamy, fertile soil that holds moisture well.

Fertilizer:  In late summer, drench plants thoroughly with water-soluble plant food.

Spacing:  Space plants 8 inches in all directions.

Blanching: When leeks are almost the size you want, blanch them for 2-3 weeks by mounding soil, mulch, or cardboard tubing around the base of each stem.

What are the best companion plants for leeks?

These are the plants that make good companions for leeks:

  • Carrots
  • Parsnips
  • Chilli Peppers
  • Peppers
  • Tomatoes
  • Celery
  • Strawberries
  • Beets
  • Brassicas
  • Onions
  • Rosemary
  • Thyme
  • Chamomile
  • Nasturtium
  • Marigolds
2 rows of leeks growing next to a brassica patch as companion plants.

Vegetable and Fruit Companions For leeks

There are so many beautiful vegetables and fruit you can plant side by side with your leeks, from root crops like carrots, beets, and parsnips to nightshades and brassicas and a few in between:

Carrots

I always interplant my carrots with my leeks. Every year, my favorite-looking bed is the leeks and carrots; they always look perfect together.

Carrots make the best companion plants for leeks, hands down. Both plants have fly pests that cause damage and spread disease. Carrots will help repel onion flies and leek moths, and leeks will help repel carrot rust flies.

I have never had a problem with carrot rust flies in all my years of gardening, but I have had issues with onion fly maggots but never in my leek and carrot bed.

Carrots are also said to help improve the flavor of leeks.

Parsnips

Parsnips also make good companion plants for leeks. Like carrots, the leeks help disguise the scent of the parsnips, warding off pests like carrot flies.

Parsnips and carrots will also help break up soil and improve aeration.

Chili peppers, sweet peppers, and tomato plants

Leeks will help deter pests like aphids and ants from your nightshade vegetables like peppers and tomatoes.

Leeks also take up very little growing space in the garden and can be interplanted around the tomatoes and peppers to help fill in gaps.

Learn More:

Beets

Beets and leeks share similar care preferences and will grow side by side. As a result, leeks will help deter some pests that attack beet greens. In addition, interplanting vegetables like leeks in between root crops like beets help make the most out of small garden spaces.

Learn More: Best Beet Companion Plants

Strawberries

Leeks and strawberries make good friends. Companion planting leeks will keep many strawberry pests away. 

Learn More: Strawberry Companion Plants

Apple Trees

If you have fruit trees in your garden or plan to add fruit trees, you should consider building a guild. For those unfamiliar, a fruit tree guild is a permaculture method of planting a tree in combination with other plants. The tree and plants will collectively grow together to create a mini-ecosystem around the tree.

For apple trees, leeks are one of the best plants to add to a guild. Plant the leeks around the tree’s base to help prevent apple scab and other fungi that can impact apple trees. Leeks will also help prevent and repel pests.

Celery

Celery and leeks are grown in a trench, making growing both together an easy endeavor. The two plants enjoy similar growing environments and share the same nutrient needs, like potassium.

Leeks protect celery from carrot root flies, aphids, and leaf miners.

Learn More: Celery Companion Plants

Onions (Yes and No)

You can grow other allium plants like onions, green onions, garlic, and shallots alongside leeks. They require similar growing environments and can get along very well planted side by side.

But only plant onions and other alliums sparingly near your leeks. Although the plants can grow together just fine, having a monoculture (planted area of the same family) can cause environmental challenges. Members of the allium family share similar pests and diseases, and if one gets a foothold into your garden bed, it can spread rapidly and be a challenge to treat and stop.

Learn More:

Brassicas

Members of the cabbage family, like Brussels sprouts, cabbage, cauliflower, kale, and broccoli, make decent neighbors for leeks. The plants do not compete at the same root level for water or nutrients, and all generally enjoy the same growing environment.

The strong scent of the leeks can help deter aphids and cabbage worms.

 

Leeks growing adjacent to strawberries and carrots. The image is to illustrate the many companion plants for leeks.

 

Aromatic Herbs As Companions For Leeks

Interplanting herbs in the vegetable garden is always a good idea. Herbs entice pollinators like bees and butterflies to the garden. They also attract beneficial insects like lacewings, ladybugs, and parasitic wasps, which will help deal with harmful pests.

Rosemary & Thyme

Rosemary and thyme are said to help enhance the flavor of leeks. In addition, both herbs will encourage beneficial insects to the garden bed to help with insect pests.

Plus, rosemary and thyme look fabulous growing in the garden.

Chamomile

This flower has plenty of benefits for the garden and is an excellent neighbor to plant next to leeks. It attracts pollinators with its sweet scent and is anti-fungal and anti-bacterial, which will help protect your leeks. Chamomile is also said to help improve the taste of members of the allium family (leeks, onions, shallots, garlic).

  • Learn More: Chamomile is a wonderful addition to any flower garden and makes a fantastic companion plant, but have you ever considered creating a dedicated tea garden? We have a guide for you if a tea garden has always been something you want to grow!

Flowers as Companion Plants With Leeks

Who doesn’t love a little pop of flower color in the garden? Beyond the lovely addition of color, flowers make to a veggie patch, they also provide several incredible benefits:

Nasturtiums

Nasturtiums help repel insect pests like squash bugs and cucumber beetles. They also act as a trap crop for flea beetles and aphids.

The flowers will help attract beneficial insects like ladybugs and parasitic wasps, which will help deal with insect pests.

Provide ground cover. Plants like nasturtiums that spread across the ground serve as a living mulch that will help suppress weeds and keep moisture from evaporating in the mid-day sun.

Marigolds

Marigolds make excellent companions for leeks. The strongly scented flowers have many benefits!

Attract beneficial predatory insects:  Marigolds attract helpful insects like parasitic wasps hoverflies, and ladybugs. Ladybugs, in particular, will feast on aphids infestations.

Repel harmful insects: Marigolds’ strong aroma works as pest control for common garden pests such as squash bugs and tomato hornworms. The flowers are also a favorite food of slugs, spider mites, and Japanese beetles, making them an excellent trap crop in the garden.

Help improve the soil:  Turning the marigold flowers into the ground at the end of the season helps kill pests like root-knot nematodes. Or the plants provide a living mulch to help keep the soil cool and moist. Be sure to use French marigolds and Mexican marigolds if you intend to help fend off nematodes.

They help control weeds: Densely planting marigolds around veggies like beans or in open spaces around other veggies makes it difficult for weeds to take hold.

Companion planting can help with disease issues. Diseases are spread more quickly through your garden when plants of the same type are planted in a large grouping. Adding different species throughout the planting can help break up the garden and slow the spread of diseases.

Leeks growing size by side with marigolds in a sunlit garden. The image is to illustrate the many companion plants for leeks.

 

What Not To Plant With Leeks

It is important to pick the right companion plants for your garden. Not every plant will be beneficial; some will cause poor growth and encourage disease and pests. You will want to avoid these bad companions for leeks:

Beans, Bush Beans & Peas

Beans are considered allelopathic plants, which means they produce biochemicals that can hinder the growth of leeks. Therefore, growing beans, broad beans, pole beans, peas, or any member of the legume family next to leeks will cause stunted growth of beans and leeks.

Asparagus

Asparagus and leeks require much different growing environments. To accommodate one, you will need to disadvantage the other. It’s best to keep alliums out of your asparagus bed.

Learn More: Curious what you CAN plant with asparagus? Check out this list of asparagus companion plants!

 

An image of freshly harvested leeks and onions in a rustic setting.

Want to Learn More About Companion Planting?

We have loads of information about companion planting in your home gardens:

Author: Laura Kennedy

Writer & Owner of Little Yellow Wheelbarrow

Laura is a highly skilled gardener and fervent flower enthusiast. Despite her playful battle with plant spacing guidelines, Laura’s work inspires gardeners to create thriving, beautiful spaces that reflect both creativity and sustainability.

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