A raised bed is any garden bed that is raised above the natural surface of the soil. Raised beds help you avoid stepping on your garden soil. In contrast to big in-ground plots, raised beds help you focus on the areas where plants will be growing, so you save on fertilizer, compost, water, time, and labor. Raised beds also warm up sooner in spring so you can plant earlier.
The benefits of raised beds can be achieved by mounding soil and/or compost, but the soil will erode over time, becoming prime ground for weeds. To avoid this problem you can build retaining walls of concrete blocks, rocks, or boards (avoid lumber painted with lead-based paint and pressure-treated lumber manufactured before 2002; also avoid creosote-treated lumber such as railroad ties).
Build your raised beds no more than 3- to 4-feet wide so that you can easily reach the middle from the paths on either side of the bed. If you have more than one bed, separate beds with pathways. You’ll need at least 18 inches for a footpath and 24 to 36 inches for using wheelbarrows and garden carts.
If filling your beds with soil from the earth, be sure to loosen it well. You can also purchase soil for raised bed, or mix your own with equal parts top soil, compost, and vermiculite.
For more on building raised beds, see this OSU Extension pdf.
Next up: Planting seeds