How can I create a DIY concrete planter?

To create a DIY concrete planter, you will need concrete mix, a mold (such as a plastic container), water, a mixing container, a stirring stick, and a release agent (such as cooking spray). First, mix the concrete with water according to the instructions on the package. Then, coat the mold with the release agent. Pour the concrete mixture into the mold and tap it to remove air bubbles. Let it dry for at least 24 hours before removing it from the mold. Sand any rough edges and paint or seal the planter as desired.