When dreaming of an ideal garden, one often imagines a neat and orderly, well-weeded and organized garden, not necessarily an overgrown forest, right?  Well…in some ways a forest can set a great example for your garden.  Biodiversity is nature’s very organized plan for mixing things up.  The wide range of plants and animals found in natural fields and forests can be a model for our gardens in creating a diverse inter-planting of crops called polyculture. The term polyculture, as defined by Wikipedia, is “agriculture using multiple crops in the same space, in imitation of the diversity of natural ecosystems, and avoiding large stands of single crops, or monoculture,” and is a fancy word for Companion Planting.  It will enhance your ability to fend off pests and disease, make the best use of your garden space, protect your soil, and increase yields… and maybe even beauty.  Method to your Madness Companion planting does not necessarily imply a mixed-up mess of a garden.  In addition, it does not mean that interplanting any crops will work in your favor either.  There is actually a science to all of this, which can lead to a very intricate dance for the experienced companion planter.  For the beginner, a few simple guidelines can propel you into a love affair with the polycultural medley of companion gardening:
  • Plant a diverse array of crops in wide rows or blocks instead of mono-cropping in single rows;
  • Interplant flowers and herbs to attract beneficial birds and insects and fend off the pesky ones; and
  • Provide habitat to attract and perpetuate the beneficials.
I have included a chart (see below) from The Encyclopedia of Organic Gardening that lists crop types and their time-tested companions, which may help you to organize your efforts.  Furthermore, there are a few companion planting rules that I gleaned from the book Great Garden Companions by Sally Jean Cunningham. It’s a Beautiful Day in the Neighborhood “Choosing plants and grouping them into families and friends to make garden neighborhoods” is one of Cunningham’s “favorite parts of companion gardening.”  She recommends that you group together crop families from your veggie wish list, from which you can assign their favorite plant friends to interplant.  Together these families and friends create neighborhoods. Each year, you can easily rotate each neighborhood to a different location of your garden for the purpose of crop rotation. The first step is to categorize your crops into families, keeping in mind that plant families can be grouped in many different ways, such as:
  • Genetically related crops with similar growing needs,
  • Crops with similar nutrition requirements,
  • Crops that help each other to grow symbiotically, and
  • Crops that lure or repel pests from one another.
Herbs and Flowers Make Great Friends Once you have grouped your crop families, next you will want to find plant “friends” to interplant among your families, thus a neighborhood is created. In many instances, these garden friends consist of flowers and herbs which provide a wide array of aromas that either attract beneficial insects or repel the pesky ones, while adding splashes of color and visual diversity…and in some instances include living mulches that help protect and build the soil while suppressing the weeds. Examples of different attributes of your garden companions are:
  • attracting beneficial insects,
  • repelling pests,
  • trap crops for luring pests away from your desired harvest,
  • weed suppression,
  • attracting pollinators,
  • providing ground cover, and
  • soil building.
While you can’t go wrong with interplanting herbs and flowers among your vegetable crops, some choices are better than others.   For example, strong smelling plants like marigolds and basil, while toted as pest repellants, actually serve to confuse pests from finding their desired meal.  Flowers in the Aster family attract beneficial insects.  Nasturtiums provide a nice habitat for predatory insects.  Sweet alyssum can be under-sown as a living mulch among Brassicas.  Dill attracts predatory wasps and works well interplanted with Brussels sprouts.  Tansy is “the singe best plant for luring beneficial (insects) to the garden and keeping them there,” says Cunningham.  For a complete example of Sally Cunningham’s neighborhood planting scheme, you’ll have to get her book, which is, in my opinion, a worthwhile investment for the beginner companion gardener. The Hospitable Habitat One of the most important aspects of the companion planting theory is attracting beneficial insects, birds, and reptiles to your garden…and more importantly, keeping them there.  All living beings require food, water, and shelter.  Aside from the obvious meal (garden pests), benficials love to indulge in pollen and nectar, which will be abundant in your diverse array of veggies, herbs, and flowers. Adding rocks and pebbles to your birdbath will provide a way for insects to access water as well as the birds, or creating “bug-baths” on the ground using pie plates or something of the like.  Shelter can be created using hedges, perennials, living mulches, and even rock piles. There is lots of advice out there for organic gardeners about natural pest control, building organic matter in your soil, attracting pollinators, etc., but companion gardening wraps it all up in a single package.  It will allow you to create a symbiotic relationship between your crops, insects, wildlife, and ultimately your dinner plate.   Companion Planting chart from The Encyclopedia of Organic Gardening, J.I. Rodale
Plant Companion(s) and Effects
Asparagus Tomatoes, parsley, basil
Basil Tomatoes (improves growth & flavor); said to dislike rue; repels flies & mosquitoes
Bean Potatoes, carrots, cucumbers, cauliflower, cabbage, summer savory, most other veggies & herbs
Bean (bush) Sunflowers (beans like partial shade, unless you live up north, sunflowers attract birds & bees for pollination), cucumbers (combination of heavy and light feeders), potatoes, corn, celery, summer savory
Bee Balm Tomatoes (improves growth & flavor).
Beet Onions, kohlrabi
Borage Tomatoes (attracts bees, deters tomato worm, improves growth & flavor), squash, strawberries
Cabbage Family (broccoli, brussels sprouts, cabbage, cauliflower, kale, kohlrabi) Potatoes, celery, dill, chamomile, sage, thyme, mint, pennyroyal, rosemary, lavender, beets, onions; aromatic plants deter cabbage worms
Caraway Loosens soil; plant here and there
Carrot Peas, lettuce, chives, onions, leeks, rosemary, sage, tomatoes
Catnip Plant in borders; protects against flea beetles
Celery Leeks, tomatoes, bush beans, cauliflower, cabbage
Chamomile Cabbage, onions
Chervil Radishes (improves growth & flavor).
Chive Carrots; plant around base of fruit trees to discourage insects from climbing trunk
Corn Potatoes, peas, beans, cucumbers, pumpkin, squash
Cucumber Beans, corn, peas, radishes, sunflowers
Dead Nettle Potatoes (deters potato bugs)
Dill Cabbage (improves growth & health), carrots
Eggplant Beans
Fennel Most plants are supposed to dislike it.
Flax Carrots, potatoes
Garlic Roses & raspberries (deters Japanese beetle); with herbs to enhance their production of essential oils; plant liberally throughout garden to deter pests
Horseradish Potatoes (deters potato beetle); around plum trees to discourage curculios
Hyssop Cabbage (deters cabbage moths), grapes; keep away from radishes
Lamb's Quarters Nutritious edible weeds; allow to grow in modest amounts in the corn
Leek Onions, celery, carrots
Lemon Balm Here and there in the garden
Marigold The workhorse of pest deterrents; keeps soil free of nematodes; discourages many insects; plant freely throughout the garden.
Marjoram Here and there in the garden
Mint Cabbage family; tomatoes; deters cabbage moth
Nasturtium Tomatoes, radish, cabbage, cucumbers; plant under fruit trees; deters aphids & pests of curcurbits
Onion Beets, strawberries, tomato, lettuce (protects against slugs), beans (protects against ants), summer savory
Parsley Tomato, asparagus
Pea Squash (when squash follows peas up trellis), plus grows well with almost any vegetable; adds nitrogen to the soil
Petunia Protects beans; beneficial throughout garden
Potato Horseradish, beans, corn, cabbage, marigold, limas, eggplant (as a trap crop for potato beetle)
Pot Marigold Helps tomato, but plant throughout garden as deterrent to asparagus beetle, tomato worm & many other garden pests
Pumpkin Corn
Radish Peas, nasturtium, lettuce, cucumbers; a general aid in repelling insects
Rosemary Carrots, beans, cabbage, sage; deters cabbage moth, bean beetles & carrot fly
Rue Roses & raspberries; deters Japanese beetle; keep away from basil
Sage Rosemary, carrots, cabbage, peas, beans; deters some insects
Soybean Grows with anything; helps everything
Spinach Strawberries
Squash Nasturtium, corn
Strawberry Bush beans, spinach, borage, lettuce (as a border)
Summer Savory Beans, onions; deters bean beetles
Sunflower Cucumber
Tansy Plant under fruit trees; deters pests of roses & raspberries; deters flying insects, also Japanese beetles, striped cucumber beetles, squash bugs; deters ants
Tarragon Good throughout garden
Thyme Here and there in garden; deters cabbage worm
Tomato Chives, onion, parsley, asparagus, marigold, nasturtium, carrot, limas
Valerian Good anywhere in garden
Wormwood As a border, keeps animals from the garden
Yarrow Plant along borders, near paths, near aromatic herbs; enhances essential oil production of herbs