My husband and I have been growing vegetables and herbs on raised garden beds for more than 30 years now. We have moved a number of times but have recreated the raised garden beds in each location because of the many benefits. Our first home had a concrete backyard and it was the only way we could create a garden, but we appreciated the benefits so much that we have built raised garden beds at each of our subsequent homes. There are more than four benefits but these are the primary ones:

1. More Nutritious Food
The reason that raised garden beds yield more nutritious food is due to the fact that the soil is loose, deep, and rich in nutrients. It is not compacted since the gardener never walks on the soil. Plants benefit from the great drainage and speedy root development that loose soil allows. Earthworms love to call it home. Plants are placed closer together in a staggered or triangular pattern (often called square foot gardening) so that their leaves slightly overlap when they reach maturity. This means the soil stays shaded which inhibits weed growth and maintains moisture. Amendments to the garden beds that enhance the nutrient value cost less because you are not covering the pathways. Compost is added each year, mixed with the soil and peat in the beds, to replace nutrients and beneficial microbes. Healthy soil means healthy plants, which allows us to grow organic food.
2. More Abundance of food
Succession planting is easy with the raised garden. Once you have harvested the spinach, you can plant a crop of green beans in the same bed. It is easy to start a new row of lettuce or spinach each week so you have a continuous supply. Planning is important in an intensive garden like this. Once you understand the growth pattern and spread of the veggies in the garden you can combine more plants together. Spring scallions and radishes can be planted between the broccoli, cauliflower or cabbage, for example, and then harvested before these larger plants grow big enough to shade the entire bed. Keep a garden journal so you can remember where you planted the tomatoes, so that you plant them in a new location the following year and where you planted the beans that fix the nitrogen in the soil. You can also note what plant combinations work well together to control pests.

3. Easy Access
A raised garden bed is best if it is no wider than 4 feet so that the gardener can easily reach to the center of the garden bed. This is the ideal type garden for the person with physical handicaps. The person with arthritis, knee problems, or hip problems has access since they don抰 have to get to ground level or kneel on a sore joint. I often sit on a five gallon bucket with a seat when working in my garden. A raised bed garden would be accessible to a wheelchair if the pathways were built wide enough and smooth enough. It is easiest to use because of the height of the bed which can be adapted to the person or situation. Our beds have started just 8 inches above the ground but as we have added compost and mulch we have raised them much higher, up to 24 or 36 inches above the ground.
4. Less Maintenance
A raised garden bed is easy to maintain. The only tools required are a trowel and a garden rake. We sometimes use a spade to turn over the top layer but not always. I mentioned earlier that weeding is less since they pull out easier and are inhibited by the close spacing and shading of the veggies in the garden. Simple mulching with grass clippings is usually enough to stop the weeds until the plants are established. Once your organic raised garden is established it is sustained only with compost. Compost can be added from your compost bin in the spring, fall, or just any time if you use it as a mulch layer. Our beds are rich with microbes and earthworms. We have a lot of trees so in the fall we mow over our leaves and put the leaves onto the beds. In the spring they are broken down enough that we just turn them in with a spade or a trowel.
Save yourself time and money gardening on raised garden beds. You need only dig, fertilize, and water the beds, not the paths. You don抰 need to weed as much when crops grow close together, because weeds can抰 compete as well. You don抰 need a tiller because the soil is never compacted.