Park Avenue Bench and Planter


The narrow planter box mold is constructed from 3/4″ melamine with 3/4″ MDO as structure to prevent “bowing” of the walls.

What You’ll Need

Step 1 – Long Planter Form

  • The long planter form is built from 3/4″ melamine coated particle board.
  • Blue insulating foam is used to create the ‘step-down’ around the top edge and also to create the void to hold soil and a plant.
  • Because of the fluid pressure of the concrete during casting, the outside of the box is reinforced with 3/4″ plywood to prevent the walls from bowing out during casting.

Step 2 – Seal the Form

  • After the form is assembled, it’s ready to be sealed.
  • Because the box is so deep, it might help to remove one of the walls to make caulking the form easier.
  • Refer to the Corner and Seam Shaping Tools Guide for more details on creating perfect seams.

Step 3 – Install the Knockout

  • After the form is fully assembled, sealed, and with the top cap in place, the foam knockout can be installed.
  • It helps to secure one layer of foam to the bottom of the form first, and then to stick the remaining foam down in place with spray adhesive.
  • Small nails will keep the foam from moving around while it’s being glued in place.
  • The foam knockout can be covered with clear packing tape or left raw. The packing tape will give the concrete a glossy surface and will make removing the foam easier.
Next: Forming Cube PlanterPark Ave Concrete Bench and Planter - Forming the Cube Planter | CHENG Concrete Exchange

The completed planter forms can be reused for many castings. Simply take care of the molds between castings by cleaning and waxing them.