The advantages of growing flowers and vegetables in a raised bed are many. Not only can you plant more intensively in a raised bed, the watering and weeding needs are reduced considerably. You can build raised beds by simply piling up dirt, or using a wide variety of wood or stone materials.
Select a location for the raised bed that receives full sun, especially if planting vegetables.
Till an 8-by-4 foot area to a depth of 6 to 8 inches. Use a shovel to remove the tilled soil to a nearby location.
Till the remaining soil in the area to a further depth of 4 to 6 inches. Add 1 inch of compost to the tilled soil and re-till to mix the compost with the soil.
Lay in the first layer of 4-by-4 inch lumber to make a large rectangle. Continue stacking the 4 by 4 lumber until all the boards are used. This should give you a bed area approximately 12 to 14 inches above the soil level of the remainder of the garden.
Add 10 cubic feet of manure or compost to the soil you removed from the location. Blend the compost into the soil to create a good mixture of both throughout the pile.
Shovel the compost/soil mixture into the raised bed.