Companion Planting

Dear Readers,

Today I would like to touch on something I feel quite passionate about which is companion planting in the vegetable garden.

I have found that is is a difficult method to use when growing biodynamically due to the proximity of the other plants and the guidelines for biodynamic gardening include tending plants on certain days; leaf plants on leaf days for example.  This means that you are not meant to hoe/weed or fertilize plants unless it is at the correct growing period when the moon lies in the corresponding astrological signs to the plant such as Waterman for leaf plants or Taurus (The Bull) for root plants.  This is quite difficult and fiddly if you have under-planted certain crops or growing other plants very close to encourage a beneficial relationship.

What is companion planting?  Essentially, when two or more crops or plants are grown together for the benefit of either plant or both plants.  Plants are grown together for many reasons such as attracting beneficial insects to pollinate or to deter pests with odors.  This type of planting is popular in permaculture (permanent culture growing) for example, strawberries growing under fruit bushes.  It also mirrors the way nature grows for example, in a woodland or forest area, the trees grow tall whilst smaller shrubs and ground cover plants grow underneath.

Companion planting works be harnessing the natural affinities of plants such as scent caused by essential oils in the plant which deter pests for another plant.  There are some well know examples of these companion planting combinations such as:

• Tomatoes and French marigolds (Tagetes patula); the marigolds are said to deter whitefly and are popular planted inside greenhouses by the door in colder climates to reduce whitefly from entering and attacking the tomato plants within.
• Basil and tomatoes are not only a delicious combination to eat but the basil is said to be hated by aphids and will steer those pesky pests away from tomatoes and any other nearby crop favored by aphids.
• Peas and poached egg plant are an interesting combination; only the peas can be eaten but the poached egg plant is great for attracting pollinating insects like bees with their simple flowers which help to pollinate the pea flowers to get a higher yield of peas on the plants.  The poached egg plant is quite a favorite of hoverflies which their larvae love to munch on aphids.
• Clover growing in pasture fixes nitrogen in the air and releases the excess nitrogen to the grasses which improved the yield of grass.
• The Three Sisters (squash or pumpkin, corn and beans) is a companion planting system where all the plants benefit; The beans fix nitrogen from the air for food for the corn and the squash, the corn acts as a support for the beans to grow up and the pumpkin or squash grow underneath the corn and beans acting as a mulch; suppressing weeds and retaining moisture.
• The scent of the tomato plant is said to deter cabbage white butterflies and their caterpillars from brassica crops such as cabbage, kale and cauliflower.  Broken leaves of the tomato can be strewn along the row or block of plants to deter these destructive insects.
• Carrots and onions grown together deter the flies which attack them.  Onions deter carrot fly and carrots deter onion fly.
• Nasturtiums grown under corn act as a mulch, keeping the soil moist and the weeds numbers down and attract many pollinating insects.  The corn stalks support the nasturtiums as they grow.
• Radishes grown in a circle around cucumber plants reduce cucumber beetle.
• Onions or garlic grown next to lettuce are said to ward off some of the slug and snail onslaught faced by gardeners worldwide.
• Herbs such as yarrow (Achillea) and hyssop attract hoverflies and other beneficial insects to the garden.
• Parsley helps to deter pests from tomato plants.
• Onion plants sown between rows of cabbages, Brussels sprouts, cauliflower etc. masks the smell of these brassica plants to the cabbage white butterfly.
• Chrysanthemums planted about the plot reduce soil nematodes as do English pot marigolds (Calendula officinalis) and French marigolds.
• Mint is said to aid the growth of squashes and brassicas but should really be planted in a container and buried in the soil to try and keep it contained since mint is quite invasive in the ground.
• Carrots and beets (beetroot) are said to make Swiss chard thrive.
• Tansy is said to repel ants, aphids and beetles but like mint can be invasive in the ground.
• Chamomile grown next to other aromatic herbs such as rosemary is said to improve their essential oil production making them taste and smell stronger.
• Berry bearing plants attract birds to the garden which will then feed on pests such as caterpillars, aphids, beetles etc.

The list below is a combination of common plants and their companions.  The list is by no means exhaustive and some combinations may not work in your area of gardening, the key to this method of gardening is to experiment in your area to find what works for you and your climate.

Apples
Chives, nasturtiums, garlic, onions

Apricots
Basil, tansy

Asparagus
Basil, parsley, tomatoes

Beans
Carrots, cucumbers, brassicas, lettuce, peas, spinach,  parsley, potatoes, corn

Beets (beetroot)
Onions, kohl rabi, lettuce, bush (dwarf) beans

Brassicas
Beans, beets, nasturtiums, celery, mint, tomatoes, chamomile, thyme, sage, onions, leeks, potatoes, wormwood, tansy, cilantro (coriander)

Carrots
Peas, radishes, lettuce, onions, leeks, chives, sage

Celery
Tomatoes, dill, beans, leeks, brassicas

Grapes
Geraniums, tansy, basil, hyssop

Parsnips
Peas, potatoes, peppers, radishes, beans, garlic

Raspberries
Tansy

Spinach
Strawberries

Squash/pumpkins
Corn, beans, sunflowers

Strawberries
Borage, sage, lettuce, spinach

It should be noted that there are some combinations of plants which are not beneficial and hinder the growth of one another.  As mentioned above, this is only a small list and gardeners should experiment with combinations to see what combinations do not work in the garden.

Common plant antagonists include:

Asparagus
Onion, potato

Beans
Chives, fennel, garlic

Tomato
Potatoes

Carrots
Dill

Potato
Squashes, pumpkins

Do you have any plant combinations which grow successfully in your area or combinations which antagonize the growth of each other?  Let us know in the comments.