Forms for Concrete Planters

• Concrete planters can be sturdy, durable accents for your outdoor living space. You can make your own concrete planters for a fraction of their retail price. Concrete topping mix is a good option for making planters; topping mix does not contain stones and creates a smooth finish.

Sand

• Damp builder's sand is the material of choice when casting concrete forms. You can create any shape you like for concrete planters using damp sand. Pile the sand on a flat surface and make a concave opening in the center of the pile equal to the desired depth of the planter. Objects such as soccer balls, footballs and salad bowls can help create shapes in the sand. Cover the formed sand with plastic wrap, coat the wrap with a release agent and then pour the concrete into the opening. A release agent can be non-stick cooking spray, petroleum jelly and other substances that will allow the concrete form to release from the sand or mold easily. Use dowels and other small-diameter objects to make drainage holes for the concrete planter, if you like.

Wastebaskets

• Select two small wastebaskets as the forms to make a concrete planter. One wastebasket should fit inside the other to create the shape of the planter. Select a plastic or metal container for the mold. Apply a release agent to the interior of the large wastebasket and the exterior of the small wastebasket to make the dried concrete planter easier to remove. Spread a 1- to 2-inch layer of mixed concrete inside the large wastebasket, on the bottom. Insert objects for drainage holes before sitting the small wastebasket on top of the wet concrete. Fill in with more wet concrete around the sides of the small wastebasket, up to the sides of the large wastebasket.

Bowls

• Plastic bowls make good forms for concrete planters. Use the same technique as with the wastebaskets to make the planter; remember to coat the parts of each bowl that touches the concrete with a release agent. You can use the same size bowls to make the planters, the concave shape of each bowl tapers at the base, so one will sit inside the other.

Plywood

• Build a plywood form to make your own square or rectangular concrete planters. Make two boxes consisting of four sides and a bottom, but make one box small enough to fit inside the other. You can make a concrete planter from a plywood form using the same techniques used on the wastebaskets and bowls.