Companion Planting

Did you know plants have best friends and enemies?  Your garden beds might as well be a catty high school cafeteria and you don’t want the potatoes sitting down at the tomato’s table.  Ok maybe it’s not quite that bad (maybe I just have too many teenagers running around my house!).  But plants do have “friends” and just like human friendships, plant friends help each other grow.  This is called companion planting.

Science behind Companion Planting

There are plenty of ways plants can help each other out.  Tall plants (like sunflowers) can help shade shorter shade loving plants (like lettuce).  Sometimes a companion can deter pests that like to go after their friend.  For instance, nematodes love to eat melons, but hate the smell of marigolds so by planting them together you can naturally deter nematodes.

Bean vines attract beneficial insects (like spiders) that like to prey on insects that will eat your corn.  Onion’s strong smell can deter many kinds of pests.  Some companions can also enhance the taste of plants they are sharing soil with.  Basil will improve most plants, but works especially well with tomatoes.  Dill & cucumbers are another obvious pairing.

Companion plants could also be plants that compliment rather than compete for resources.  Beans help fix soil by adding in extra nitrogen – something that nitrogen loving tomatoes would appreciate. Calendula attracts a wide range of pollinators so makes a great friend for lots of plants that flower like squash and cucumbers.

The entire concept of companion planting just reinforces my belief that your garden is meant to be a diverse mix, not rows and rows of the exact same plant!  A great way to showcase companion planting is in a square foot garden – click here to learn about square foot gardening

tomatoes & calendula

Bad Pairings

With every good there comes some bad.  There are some plant pairings that you should avoid.  Potatoes & tomatoes are both members of the nightshade family and are effected by the same types of blight.  Planting them together can contribute to the spread of disease.  They also are both heavy nitrogen feeders so they could compete for resources, stunting the growth of both.  Carrots planted near tomatoes will have stunted growth due to tomato’s extensive root systems.  Onions & beans can also stunt each other’s growth.

Companion Planting Guide for Common Backyard Plants

Following is a guide to some of the most commonly found plants for gardeners.  “Friends” are plants that will help that plant, “enemies” are ones that will hinder that plant.  They aren’t always the same!  A good example is with carrots & tomatoes.  When you plant carrots near tomatoes, the carrots will be stunted by the huge root structure of the tomato.  But the tomato will grow better & be more flavorful.  So carrots are a friend of tomatoes, but tomatoes are an enemy of carrots.  Planting flowers like marigolds, calendula, sunflowers & nasturtiums not only make your garden gorgeous and more diverse, they also attract a ton of pollinators and beneficial insects so it’s a great idea to sprinkle them all around!

Asparagus
friends: tomatoes, parsley
enemies: onions, garlic, potatoes

Basil
friends: pretty much everyone, but especially tomatoes, asparagus & peppers
enemies: none

Beans, Bush
friends: beets, cabbage, carrots, cauliflower, corn, cucumbers, marigolds, potatoes, strawberries
enemies: garlic, leeks, onions, shallots

Beans, Pole
friends: corn, marigolds, potatoes, radishes
enemies: beets, garlic, leeks, onions, shallots

Brassicas (broccoli, Brussels sprouts, cabbage, cauliflower..)
friends:  beets, chamomile, dill, mint, rosemary, sage, onions, garlic
enemies: tomatoes, potatoes, eggplant, strawberries

Carrot
friends: lettuce, onions, peas, radishes, rosemary
enemies: dill, parsnips, tomatoes, potatoes

Corn
friends: beans, cucumbers, melons, peas, pumpkins, squash, sunflowers
enemies: tomatoes, celery

Cucumber
friends: beans, cabbage, corn, radishes, sunflowers, marigolds, carrots, dill
enemies: late potatoes

Eggplant
friends: green beans, peppers, potatoes, tomatoes, peas, spinach
enemies: none

Garlic
friends: cabbage, cane fruits, roses, tomato, celery, lettuce, potatoes, tomatoes
enemies: peas, beans

Lettuce
friends: beets, carrots, parsnips, radishes, strawberries, onions, cucumbers, sunflowers
enemies: cabbage, celery, parsley

Marigold (Calendula)
friends: everyone!
enemies: none

Melons
friends: corn, marigolds, nasturtiums, pumpkin, radish, squash, sunflowers
enemies: potatoes

Nasturtiums
friends: apples, beans, cabbage, potatoes, pumpkins, radishes, squash, cucumbers, tomatoes
enemies: none

Onion
friends: beets, cabbage, carrots, lettuce, parsnips, dill, strawberries, tomatoes
enemies: beans, peas, asparagus

Oregano
friends: everyone!
enemies: none

Peas
friends: beans, carrots, corn, cucumbers, early potatoes, radishes, turnip, mint, strawberries, eggplant
enemies: garlic leeks, onions, shallots

Peppers
friends: basil, carrots, eggplant, onions, parsley, tomatoes, sunflowers
enemies: beans, kale, Brussel sprouts

Potato
friends: basil, beans, cabbage, corn, eggplant, marigolds, peas, squash, garlic
enemies: carrots, sunflowers, cucumber, pumpkin, tomato, melons

Spinach
friends: celery, cauliflower, eggplant, strawberries, peas, beans
enemies: potato

Strawberries
friends: bush beans, lettuce, spinach, garlic, onions, peas
enemies: brassicas

Sunflowers
friends: cucumbers, squash, pumpkins
enemies: potatoes

Tomatoes
friends: asparagus, basil, cabbage, carrots, parsley, onions, rosemary, sage, marigold, corn, beans
enemies: fennel, potatoes, dill, walnut trees

Sorry Beyonce, you nibble on too many of my plants – chickens are not a friend of the garden! But thanks for the compost