The 4x8 foot garden beds I bought, for instance, are 4x8 feet from end to end. But when you connect the boards at the corners, you lose a few inches, so the interior dimensions of the garden bed are actually a few inches short of the advertised size. In my case, my beds have an interior dimension of 46.25 inches x 94 inches. I refer to these dimensions as Usable Length for the remainder of this article.
Elevated garden beds are a good solution for plant drainage and compacting of the soil; plants will grow much better because of these facts. Raised beds will warm up faster in the springtime and continue to stay warm longer in the fall which means you can have a longer growing season.
Vegetable garden bed construction materials should be chosen carefully. Some concerns exist regarding the use of pressure-treated timber. Pine that was treated using chromated copper arsenate or CCA, a toxic chemical mix for preserving timber that may leach chemicals into the soil which in turn can be drawn up into the plants, is a concern for vegetable growers, where part or all of the plant is eaten. If using timber to raise the garden bed, ensure that it is an untreated hardwood to prevent the risk of chemicals leaching into the soil. A common approach is to use timber sleepers joined with steel rods to hold them together.
The close plant spacing and the use of compost generally result in higher yields with raised beds in comparison to conventional row gardening. Waist-high raised beds enable the elderly and physically disabled to grow vegetables without having to bend over to tend them.