How to Build Raised Planters on a Hillside

Select the area of the hill where you want the raised planter. The side of the planter closest to you when facing the hill will be the front, while the side furthest away is the back. Drive a garden stake into the ground to mark the two front corners of the planter. Measure the distance between the stakes to find the length of the planter.

Measure from the front stakes back using a tape measure and level to find the exact point on the hill 3 feet behind each front stake. Drive garden stakes into the ground at each of these points to mark the back corners of the planter box.

Dig to remove the soil in the area between the stakes working straight down from the back corner stakes and inward between the front corner stakes. Dig until all the soil has been removed and the walls and floor of the planter area are flat and level.

Measure the height of the back wall and add 4 inches. Divide this measurement by eight and round up to a whole number. Purchase twice that number of 2-by-8 inch cedar boards the length of your planter for the front and back walls. Purchase twice that number of boards 3 feet long for the sides of the planter.

Cut four 3-by-3 posts to the height of the planter plus 6 inches. Build the planter box using your cedar boards, setting the posts inside each corner for stability. Drill two galvanized screws through the end of each board and into the support posts.

Flip the box over so the excess 6 inches of the posts are facing down. Move the planter to the prepared area of the hillside. Set the planter inside the prepared area and use a rubber mallet to drive the posts into the ground at each corner.

Multiply the length, width and height of the planter in inches to find the cubic inches. Divide this number by 1728 to convert to cubic feet. Purchase this quantity of garden soil and fill the planter.