COMPANION PLANTING

Companion planting is the practice of growing plants next to each other for mutual benefit.  Companion's attract beneficial or repels harmful insect and it can also improve the flavor or growth.  I personally have planted sweet basil next to my tomato plants because it will repel flies and mosquitoes and improve growth and flavor of the tomato.  I have planted Marigolds next to beans, peas and tomatoes because it is a natural way to deter beetles and other harmful insects.  I also love to grow mint next to beans and carrots to help improve the growth and flavor.  I have made flower and vegetable arrangements in containers for customers keeping in mind companion planting.   There is a wealth of information on the internet related to this topic.  I have tried to simplify it here for you and try to get you thinking about the planning process of your gardern.   I have attached a chart to help you get started it is published by Encyclopedia of Organic Gardening for companion planting ideas.   

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

This link is also a free reference guide that I like to refer back to.

http://www.almanac.com/content/plant-companions-list-ten-common-vegetables