Remove all weeds, grass, rocks, debris and large roots from the planting site, including the border area. Do not leave weeds under the landscape timbers since they will grow up around the timbers and invade the garden area.
Mark the edge of the border by driving 12-inch long wooden stakes into the outer corners of the border. Wrap twine around the stakes to define the border and to keep it straight. Loosen the soil up to the depth of 4 inches with a shovel. Create an 8-inch wide area all around the area that needs a border.
Add or remove soil to the border area as needed to create a level area for the landscape timbers. Use a carpenter’s level to check the ground evenness. Add extra soil to any areas that dip strongly. Peat moss, sand, potting soil or gravel may be used to fill in holes.
Spread a 1- to 2-inch layer of gravel in the border area. This gives a good footing for the landscape timbers. It also increases the drainage in the border area to protect the timbers from excess moisture. The longer timbers are in contact with water, the sooner the timbers need to be replaced.
Remove the wooden stakes and twine. Place the landscape timbers on the gravel bed. Push the ends of the timbers together tightly. Drive 8-inch wooden stakes halfway into the ground on the downhill side of any timbers located near a slope. This will keep the timber from moving in bad weather or if someone walks on them.