This type of planting will discourage insects and specific vegetable pathogens that can stay in the soil over winter and planting that same crop in that bed will infect the crop.
They are perfect for the disabled gardener, those suffering from arthritis, and the elderly as they can be elevated to a suitable level so that bending over and kneeling will not be necessary.
Some of the other benefits of raised beds are: reachable - less bending and stretching gives the gardener easy access and makes maintaining and harvesting less of a task to perform; drainage - because the soil is above the ground it will not become compacted during heavy rains and will drain properly in preventing water-soaked soil;
A double skinned wall provides an air pocket of insulation that minimizes the temperature fluctuations and drying out of the soil in the garden bed. Sometimes raised bed gardens are covered with clear plastic to protect the crops from wind and strong rains.