A deck planter is a good way to incorporate greenery into your deck or patio. Because decks are generally made of wood and not placed directly onto the ground, a deck planter must be lightweight and yet still sturdy enough to counterbalance the top weight of trees or shrubs that may be planted in them. Additionally, a deck planter should be thick enough to protect the roots of tender plants in winter. One good medium you can use to build a deck planter is hypertufa. Hypertufa is a cement derivative that simulates tufa stone.
Secure all the seams of both of your boxes with duct tape. Line the inside of the larger box and the exterior of the smaller box with a plastic dry-cleaning bag and tape the bag in place. Coat the surfaces of the laundry bags with cooking spray.
Stand the four PVC pieces on their ends inside the larger box.
Mix one part Portland cement, one part vermiculite and one part peat moss in a 5-gallon bucket. Add water gradually until the mixture is the consistency of a mud pie.
Pack the cement mixture into the bottom of the large box around the PVC pipe pieces until the box is filled to a depth that the pipe pieces are halfway covered.
Cut a piece of chicken wire with wire cutters so that it is slightly smaller than the bottom of the box. Cut holes in the wire for the four pieces of pipe. Place the chicken wire into the bottom of the box and press it into the surface of the cement mixture.
Pack more cement by hand into the bottom of the box over the chicken wire and around the PVC pipe until the cement is level with the tops of the PVC pipe.
Place the smaller box on top of the cement mixture so that there is an equal amount of space between the smaller and larger boxes on all sides. Insert chicken wire sheets into each side of the box, pressing them down into the cement mixture at the bottom of the box.
Pack the cement mixture into the spaces on all sides of the box. Tap the cement down and remove air pockets by shoving on the mixture with a dowel rod. Mist the boxes with water from a water bottle. Cover the boxes with plastic dry-cleaning bags and allow the mixture to cure for 72 hours.
Unmold the container from the boxes carefully and brush away the rough edges with a copper-bristled brush. Mist the container, wrap it in plastic and allow it to dry for another two weeks.
Spray the container with water and allow the limestone to leech out of the container for two weeks. Rinse with a solution of ¼ cup vinegar to 1 gallon of water before filling with dirt and planting.