Good Friends/Bad Friends. We all know folk we love to spend time with, and some we'd rather avoid. It's life. Some folk benefit us and some drag us down. So it is with plants. Being aware of this can give the vegetable gardener a huge advantage! Knowing which neighbors benefit from being close and ones that really can't stand each other can boost success in the raised vegetable bed.
What is it that makes a plant a good neighbor? For some it may be pest control. For example

caterpillars love nasturtiums. They also like cabbage and lettuce, as vegetable gardeners' know only to well! Thing is they much prefer nasturtiums and so planting them near to the leaf crops can distract egg laying insects. Marigolds, planted close to crops that suffer from aphids can not only repel the insect but also attract aphid predators such as the hover fly, thus delivering a double whammy. Horseradish can increase the disease resistance of potatoes when planted nearby. Peppers can benefit from the shade of tomato plants. Although the pepper plants needs direct sunlight to grow, it's fruit can be damaged by the sun. Tomatoes love the

sun and can shade the peppers. All good neighbors.

Another thing that makes a good neighbor is sharing. At times we've all enjoyed the hospitality of

neighbors whom, having extra food, have invited us round to share. Probably done the same thing yourselves. Well Plants have left overs too. For example, most varieties of bean will enrich the soil with nitrogen. They take nitrogen from the air and release it to the soil through their root system. Planting beans close to nitrogen hungry plants such as carrot, potato, strawberry and corn will benefit them a good deal. Native American Indians used to allow beans to grow up through their corn, like a trellis, thus the bean gained support and the corn gained nitrogen. Good neighbors.
Psst! Wanna know a not so secret, secret? Not all neighbors get along! Similarly, some plants just can't live next to each other. Take Alliums, for example. While some plants flourish with onions next door, others, it is said, suffer as a consequence of living next to the onion family. Carrots, lettuce and cabbage are fine but peas and beans tend to do less well. . Other poor neighbors include potatoes and tomatoes. They should be kept apart as they both can suffer from blight and may contaminate each other.

Lettuce and cabbage don't get along as the latter can damage both the growth and flavor of the former.
There is much the raised bed, vegetable gardener can gain from considering which plants are good and bad companions. The very nature of planting in beds, where the plants are much closer together makes companion planting an essential tool for the gardener to employ. While planning your beds for the coming spring keep companion planting in mind. As it is with a dinner party, who sits next to who can make a big difference to the outcome of the event! With good planning and good neighbors comes a raised bed full of happy, productive plants.
For further information on good companion plants try these links:
http://en.wikipedia.org/wiki/List_of_companion_plants
http://www.companionplanting.net/ListofCompanionPlants.html
http://hubpages.com/hub/COMPANION-PLANTING-Plant-Guide
cheers
Steve