How to Build a Planter Box with Natural Stone

Cover your work station with a large plastic tarp. This makes for easy cleanup of the sand later on. Pour a 5-lb. bag of playground sand onto the center of the tarp. Add water to the sand to moisten it. If you are able to make a ball out of the sand and it retains its shape, it is wet enough. But you do not want water to pool on the surface. Mound the sand so that it is evenly distributed and at least 12 inches deep.

Draw the general shape of the planter you want to make on the surface of the sand. Use a small trowel to dig out the shape in the sand. Leave a 2-inch layer of sand at the bottom.

Place natural stones into the carved-out sandcast. Press the stones against the sides of the mold. Smooth the base of the sandcast with your hands. If the sand is not easily pliable, add a little more water.

Prepare a bag of quick-set cement in a bucket, according to the manufacturer's instructions. You want the cement to be able to cling to the sides of the stones as it sets. Wear rubber gloves when working with the cement to avoid over-drying your hands. Wear a mask to avoid respiratory irritation.

Scoop handfuls of the cement out of the bucket you prepared it in and apply it to the inside of the sandcast mold. Press the cement into the bottom of the mold as well as up the sides and in between the stones. You want a 1/2-inch to 3/4-inch layer all around.

Spray the ends of two 1/2-inch-diameter dowel rods with non-stick cooking spray. Insert the two dowel rods through the cement and into the sand of the sandcast. These will make the drainage holes for your planter.

Allow the cement to set a minimum of 24 hours. Remove the dowel rods. Carefully remove the dried cement and stone box from the sand and use a clean paint brush to brush away the sand on it before planting in your completed box.