What are Companion Plants?
Companion gardening is something that many people have heard of, but not many actually know or understand what it is or how it works! Companion gardening involves planting a combination of plants that actually complement each other and contribute to the growth and productivity of each other. Different companion plants help each other by deterring pests, promoting growth, improving flavor, and more! Similar to certain plants being compatible in this way, some plants are very incompatible and can even contribute to stunted growth and decreased productivity.
What are the Benefits of Companion Planting?
As we said above, there are many benefits to grouping compatible plants in your garden. Here are a few ways that companion plants help benefit and support each other:
Natural Supports
Plants that grow strong and tall can help benefit plants that are low-growing or vining plants. One example of such a pair could be sunflowers and snap peas. The peas can use the sunflowers as a sort of trellis, while also helping to stabilize the sunflower by giving it another point of contact to the ground. In this scenario, both plants help each other out.
Plant Health
Compatible plants will naturally not be in competition with each other for things such as nutrients or water in the soil. This makes it so that one plant can absorb what it needs without depriving its neighboring plant of its necessities. In addition to this, one plant pulling certain nutrients from the soil affects the makeup of the soil and the nutrients that another plant absorbs, which in turn can improve the flavor of other plants nearby, if paired correctly.
Nutrients in the Soil
Similar to what was just mentioned above, certain plants can also make different nutrients more readily available to other plants in the area. For example, plants with roots that reach deeper into the soil, such as carrots or parsnips, will help pull nutrients up into the more shallow layers of soil where they will be more accessible to other plants that need those nutrients.
Weed Prevention
Planting companion plants can help reduce the population of weeds in your garden as well! For example, alternating upright and sprawling plants results in the open space of your garden becoming more densely covered. The desirable plants in your garden will have the space they need due to the strategic alternation. However the increased density of your garden layout will not provide weeds with as much room under the sun to grow, and therefore this layout will help crowd out the undesirable weeds.
Regulate Shade and Wind
While your garden fruits and vegetables need lots of sun to grow strong and produce a healthy crop, too much sun can damage the more tender plants in your garden. Planting companion plants in the same vicinity will help to shade some of the more sun-sensitive plants while allowing the sun-thirsty plants all they could need. Similarly, plants that tend to grow taller and stronger will serve as a sort of wind block for plants that are more likely to be damaged by strong winds.
Popular Companion Plant Combinations
Now that you know what companion planting is and have had a chance to hear about all the benefits companion planting offers, we have compiled the following list of compatible plants, as well as a list of plants that should be kept separate, so that your garden can flourish like never before.
Asparagus
- Compatible plants: Basil, carrots, coriander, dill, marigolds, parsley, tomatoes
- Incompatible plants: Garlic, onions, potatoes
- Special notes: Marigolds, parsley, and tomatoes protect against asparagus beetles.
Basil
- Compatible plants: Asparagus, beans, beets, bell peppers, cabbage, chili peppers, eggplant, marigolds, oregano, potatoes, tomatoes
- Incompatible plants: Rue
- Special notes: Grow basil approx. 1 foot from tomato plants to increase the tomato plant's yield. It also improves the flavor of lettuce.
Beans
- Compatible plants: Beets, carrots, chard, cabbage, corn, cucumbers, peas, radishes
- Incompatible plants: Garlic, onions
- Special notes: Nasturtiums and rosemary deter bean beetles
Beets
- Compatible plants: Broccoli, Brussels sprouts, bush beans, cabbage, cauliflower, chard, kohlrabi, onions
- Incompatible plants: Charlock, field mustard, pole beans
- Special notes: Pole beans and beets will compete for growth. Composted beet leaves add magnesium to the soil when mixed. Magnesium plays an important role in photosynthesis.
Broccoli
- Compatible plants: Basil, beets, bush beans, carrots, celery, chamomile, cucumber, dill, garlic, lettuce, marigolds, mint, nasturtiums, onions, radishes, rosemary, sage, spinach, Swiss chard, thyme
- Incompatible plants: Asparagus, cantaloupe, climbing beans, mustard, pepper plant, pumpkins, strawberries, sweet corn, watermelon
- Special notes: Rosemary repels the cabbage fly that is detrimental to broccoli.
Cabbage
- Compatible plants: Beets, celery, chard, lettuce, spinach, onions
- Incompatible plants: Kohlrabi, tomatoes
- Special notes: Hyssop, mint, and sage deter cabbage moths
Carrots
- Compatible plants: Beans, lettuce, onions, peas, peppers, tomatoes
- Incompatible plants: Dill
- Special notes: Chives improve flavor, rosemary deters carrot flies
Corn
- Compatible plants: Climbing beans, cucumber, marjoram, peas, pumpkins, squash, sunflowers, zucchini
- Incompatible plants: Tomatoes
- Special notes: Tomato worms and corn earworms like both plants. Beans and peas supply nitrogen.
Marigolds
- Compatible plants: Marigolds help virtually any vegetable, particularly tomatoes.
- Incompatible plants: Beans, cabbage
- Special notes: Marigolds ward off many insects including nematodes which like to attack the root systems of vegetables.
Mint
- Compatible Plants: Oregano, marigolds, carrots, cabbage, cauliflower, kale, tomatoes, eggplant, peas, beans
- Incompatible Plants: Other herbs such as lavender, rosemary, sage, and thyme.
- Special notes: Mint is great for repelling unwanted insects such as cabbage moths, flea beetles, aphids, spider mites, and other varmints.
Onions
- Compatible plants: Cabbage, carrots, chard, lettuce, peppers, tomatoes
- Incompatible plants: Beans, peas
- Special notes: Chamomile improves growth and flavor
Potatoes
- Compatible plants: Basil, beans, celery, corn, garlic, horseradish, lettuce, marigolds, onions, peas, radishes, spinach
- Incompatible plants: Asparagus, broccoli, Brussels sprouts, cabbage, cauliflower, carrots, cucumbers, eggplant, kohlrabi, melons, peppers, raspberries, squash, sunflowers, strawberries, tomatoes
- Special notes: Cucumbers, tomatoes, and raspberries attract harmful pests to potatoes. Horseradish increases disease resistance.
Pumpkins
- Compatible plants: Beans, corn, marigolds, nasturtiums, squash
- Incompatible plants: Potatoes
- Special notes: None.
Radishes
- Compatible plants: Beets, cabbage, carrots, chives, cucumbers, kale, lettuce, spinach, squash
- Incompatible plants: Hyssops
- Special notes: Radish plants will work as a trap crop to protect against certain beetles.
Squash
- Compatible plants: Beans, corn, dill, marigolds, nasturtiums, peas, radishes, strawberries, sunflowers
- Incompatible plants: Potatoes
- Special notes: Squash has similar traits to pumpkin in terms of companion plants.
Strawberries
- Compatible plants: Bush beans, caraway, chives, lettuce, onions, sage, spinach, squash
- Incompatible plants: Cabbage family, eggplants, peppers, potatoes, tomatoes
- Special notes: None
Tomatoes
- Compatible plants: Asparagus, carrots, celery, onions, parsley, peppers, dill, basil
- Incompatible plants: Corn, dill, kohlrabi, potatoes
- Special notes: Basil, mint, and bee balm improve growth and flavor. Dill and basil naturally protect tomato plants from hornworms.
Zinnias
- Compatible plants: Zinnias pair well with any garden vegetable, especially beans, tomatoes, squash, and peppers.
- Incompatible plants: None
- Special notes: Zinnias are excellent garden companions as they attract ladybugs which help keep unwanted bug populations at a minimum. They also attract many other pollinators.
Zucchini
- Compatible plants: Beans, corn, dill, garlic, marigolds, nasturtiums, oregano, peas, radishes, spinach
- Incompatible plants: Potatoes and pumpkin
- Special notes: None
Have Questions About Companion Gardening?
This is certainly not an exhaustive list of all of the different fruits, vegetables, flowers, and herbs that can benefit each other. There is so much to know on the topic of companion gardening that it is impossible to cover it all in one blog post! So, if you have any questions at all, please let us know! We are happy to help in any way we can and it is our greatest joy to help gardens across Colorado flourish and thrive.
Sources:
"Marry Your Flowers and Veggies: Companion Planting Guide to Your Garden." Gilmour. Date Accessed: 14 July 2021. https://gilmour.com/companion-planting-chart-guide