Next you are ready to rout the cavity that will hold the sand for the dry garden. Proceed cautiously with this step because if performed improperly, it can be dangerous. You need to create a template that will guide your plunge router around the periphery of your cut. Simply cut a window out of a piece of plywood, MDF, or particle board taking into account the dimension of the wood you are routing and the distance between the router bit and the edge of your router's base. We left about 1" (25mm) between the edge of the cavity and the outside edge of the board - this will serve as the frame of the dry garden. A larger dimension is recommended to ensure that your router will have a sufficient surface to ride on and you proceed.

Next, using double-sided tape, securely fasten the wood you are cutting onto a flat surface. Place some spacers all around the wood, and then securely clamp the template on top of the spacers. Now you are ready to plunge into the wood and remove the material. Note that you will not be able to make repeated passes increasing the depth each time because there won't be enough surface for your router's base to ride on; so you will have to complete this in one step. We recommend routing out the entire perimeter of your cut, and then remove the remaining material by making repeated passes as you move along the board. Always ensure that the wood is being fed into the direction of the cut.