Collect old wood shipping pallets. Many big box stores, grocery stores and other places of business get their products delivered on wooden pallets, and they may be willing to give them away to anyone who asks, especially if the pallets are damaged and cannot be reused for shipping. Factories and landfills are other good places to look for pallets. Always ask permission before taking pallets; even if they look abandoned, the business may be planning on reusing them, or may have offered them to somebody else. If you have a choice, look for pallets made of hardwood, since they will last longer and be easier to work with.
Use a pry bar or the claw end of a hammer to carefully pry apart the pallet. The wood may want to split around the nail, so take your time and work carefully. If you can't pry the boards apart without the wood splitting, saw the boards off with a hand saw or circular saw. Avoid sawing through nails.
Trim any damaged, splintering or rough ends of the boards with a saw.
Sort the wood into like-sized pieces. You will be using the boards to build squares or rectangles that are two board-widths tall. As an example, let's say we are building a raised bed that is four feet long and two feet wide, so we will need four four-foot boards and four two-foot boards, plus shorter pieces for reinforcements.
Lay two four-foot boards flat on the ground side by side and measure their combined width. Use a saw to cut a piece of wood that long. Nail the reinforcement across the two four-foot boards flush with the edge of one of the short ends.
Repeat step five to create another four-foot section and two two-foot sections.
Arrange the sections to create a rectangle, making sure a reinforced end is on the inside of each corner
Nail the sections together, driving the nail through the reinforcement.
Stretch chicken wire across one end of the raised bed and attach it with a staple gun. This is an optional step that will help keep moles and other burrowing animals out of your garden, although it may also limit which root vegetables you can grow.
Lay the raised bed on ground with the chicken wire side facing down, and fill it with soil, compost and garden plants.