- Kelsey Andrus
- Thursday, April 18
Did you know that some plants can help or hinder other plants in your garden? Choose partners wisely.
Companion planting has been around for millennia, and is particularly useful for organic gardens that do not use chemical pesticides and fertilizers. This gardening method utilizes the strategic placement of certain herbs, flowers, and vegetables near other plants to employ mutual benefits and enhance crop production. These benefits can be retaining moisture in the soil, providing shade, attracting beneficial insects and pollinators, building nutrients in the soil, or deterring pests and the spread of disease. When looking for good planting partners, one must understand which plants help each other and which plants compete with each other.
In this post, I will cover the basic knowledge needed to start companion planting and offer some suggestions for which plants are advantageous in the same area and which like to be a bit farther away from each other, paying particular attention to what is available in our Seed Library collections across the system.
One of the most well known examples of companion planting is the Native American Three Sisters Garden, which has corn, beans, and squash growing together. The corn grows tall, providing a natural trellis for the beans to grow up. The beans, in turn, fix nitrogen into the soil, feeding the corn and squash plants. The squash has broad fuzzy leaves which shade the soil, retaining moisture and suppress weeds, while deterring grazing animals with the fuzzy spikes. This grouping of plants yields stronger crops with high production when grown together, requiring less input from the gardener.
When utilizing the companion planting method, the first basic principle is knowing which plants do or don't do well near each other. Plants that are well suited, should be planted within 2 rows, or a few feet, of each other. Plants that don't do well should be planted 2-3 rows, or several feet, apart. This will intermingle your herbs, flowers, and vegetables in the same beds or containers for a beautiful and productive display.
Another principle of good companion planting is to utilize crop rotation for annual crops year to year. This means not planting the same plant (or plant family) in the same spot in the garden from one year (or season) to the next. This will ensure that pests or diseases that predate on certain plant families don't build in the soil. For instance, last year my potatoes got a disease known as blight which attacks anything in the nightshade family, so I should not plant tomatoes, peppers, eggplant, or potatoes in that bed for a few years to let the fungus that causes blight to die out.
The final principle to start you on your companion planting journey is to plant a wide variety of flowers, herbs, and vegetables. This will help deter disease and will call a diversity of beneficial insects to the garden, encouraging pollination of vegetables as well as calling predator insects that will help control pests. There are many insects and birds that act as pollinators, so having an array of flower head types will attract pollinators of different mouth and feeding types. Having an assortment of flowers, herbs, and vegetables will also benefit the soil by bringing in different growth types and nutrient fixers into the space. For example, having root vegetables like radishes will alleviate soil compaction while deep rooted plants, like asparagus and sunflowers, help draw nutrients and water closer to the surface.
Planting Partners
Universal companions
- basil, borage, calendula, mints (in pots), nasturtiums, thyme
Asparagus
- companions: lavender, marigolds, oregano, strawberries
- avoid: beans, garlic, leeks, onions, potatoes
Beans
- companions: clover, corn, cosmos, dill, potatoes (among many others)
- avoid: chives, garlic, gladiolus, onion, peppers
Beets
- companions: bush beans, cabbage, carrots, lettuce, onions
- avoid: mustard greens, pole beans
Cabbage Family
- companions: alyssum, beets, chard, dill, onions, rosemary, sage, spinach, sunflowers
- avoid: beans, fennel, strawberries, tomatoes
Carrots
- companions: cabbage family, chives, cosmos, lettuce, onions, peas, peppers
- avoid: dill, tomatoes
Celery
- companions: cabbage family, onion, tomatoes
- avoid: corn, potatoes
Chives
- companions: cabbage family, parsley, sage, tomatoes
- avoid: asparagus, beans, peas, spinach
Corn
- companions: beans, cucumber, peas, pumpkins, squash, sunflowers
- avoid: celery, tomatoes
Cucumbers
- companions: clover, corn, dill, lettuce, onions, parsley
- avoid: sage
Lettuces
- companions: alyssum, broccoli, carrots, dill, onions, radish, spinach, squash, tomatoes
- avoid: celery, parsley
Onion family
- companions: alyssum, beets, cabbage, carrot, cosmos, lettuce, strawberries, tomatoes
- avoid: asparagus, beans, peas
Peas
- companions: cabbage family, carrot, lettuce, mustard, potatoes
- avoid: garlic, onion
Peppers
- companions: basil, garlic, golden alexanders, onion, oregano, parsley, sunflower, tomatoes
- avoid: beans, cabbage family
Squash
- companion: beans, clover, corn, golden alexanders, radishes, zinnias
- avoid: plant hubbard squash well away as a decoy for pests
Tomatoes
- companion: basil, borage, celery, marigold, nasturtium, onion family, parsley, radish
- avoid: cabbage family, carrots, fennel, potatoes