How to Build a Simple Raised Garden Bed

Select a level spot that receives at least 6-8 hours of direct sunlight per day. Avoid low spots where water pools. Place the bed on grass, bare soil, or gravel — not on concrete (you need drainage). Mark the 4x8 foot footprint with stakes and string or spray paint.

You need four 8-foot boards for the long sides and four 4-foot boards for the short sides (cut four of your eight-footers in half). Cut four 12-inch pieces of 4x4 for the corner posts. If your lumber yard sells 4-foot boards, you can skip cutting the short sides. Sand any rough edges.

Stand a long board on edge and butt a short board against the end, forming a right angle. Place a 4x4 corner post inside the joint. Drive three 3-inch deck screws through each board into the corner post. Repeat for all four corners. For a 10-inch-tall bed using 2x10 boards, one course is enough. For a taller bed, stack a second course on top and screw through into the course below.

Move the assembled frame to your marked location. Set it in place and check for level with a 4-foot level across the top edges. If the ground is uneven, dig out the high spots rather than shimming the low spots — the frame should sit firmly on the ground with no gaps (gaps let soil wash out). If the ground slopes, step the bed into the slope and add soil inside to level the planting surface.

Line the bottom of the bed with landscape fabric to suppress weeds from growing up through the soil. Overlap seams by 6 inches. Staple the fabric to the inside of the boards. The fabric allows water to drain through while blocking weeds. Some gardeners skip this step if building over bare soil and prefer to allow worm access from below.

Fill the bed with a mix of 60% topsoil, 30% compost, and 10% perlite or vermiculite. This blend provides nutrients, drainage, and aeration. A 4x8x10-inch bed needs about 1 cubic yard of soil mix (27 cubic feet). Water the soil thoroughly after filling to settle it, then top off to within 1 inch of the frame top. Let the soil settle for a few days before planting.

Plant your vegetables, herbs, or flowers according to the spacing guidelines for each variety. Water immediately after planting. Apply 2-3 inches of mulch (straw, wood chips, or shredded leaves) around the plants to retain moisture, suppress weeds, and regulate soil temperature. The raised bed is now ready to grow.