Concrete planters are one of the best planter choices for plants you grow outdoors year-round. The planters are sturdy enough to prevent tall plants such as ornamental trees from tipping and are thick enough to prevent plant roots from freezing through long winters. Commercial concrete manufacturers have made it simple to build concrete planters by providing concrete mixes and dyes that are simple to work with, as well as concrete molds that make forming a planter simple.
Fill the plastic waste basket with sand to give it weight. Oil the outside with vegetable oil so that the waste basket will release from the concrete mold easily.
Combine water and crack-resistant concrete mix gradually in a 5-gallon bucket until the mix is the consistency of cake batter. Stir with the plastic stirring rod. If you wish to change the color of your planter, add liquid cement color to the mix.
Snap together the reusable concrete furniture mold and rub the interior with vegetable oil. Pour a 3-inch-thick layer of cement into the bottom of the mold.
Coat the surface of the dowel rod and push it through the concrete mix in the center of the bottom of the mold to create the drain hole. When the cement dries, you will push the dowel rod out of the hole.
Place the waste basket into the mold over the poured concrete base. Center the bottom of the basket over the dowel rod.
Pour concrete into the space in between the sides of the waste basket and the sides of the mold. Remove air pockets by tamping the concrete down into the mold with the tamping tool. Fill the mold completely to the top.
Spray the container's top with water from a spray bottle and wrap the container in a dry-cleaning bag to cure. Water will make concrete dry and cure into a stronger substance. Allow the concrete to cure for four days.
Pull the waste basket free of the inner concrete form by grasping the inner sides of the waste basket and twisting as you pull upward. Turn the reusable mold over so that the open side faces downward. Remove the mold in its pre-assembled pieces. Be careful as you unmold the planter. The surfaces will be brittle at this point.
Rub the concrete planter with a copper brush to smooth out rough edges. Push the dowel rod out of the planter to open the drain hole. Spray the planter with a mist of water and wrap it in plastic to finish curing for another four days.