Overtime debris or roots can reach into your overflow drain. If your planter is empty, just turn it around and use a wire hanger or skewer to penetrate the overflow drain. Do not use a wood utensil, as it may break off in the overflow drain. If planted, empty your water cavity first by releasing the main drain on your planter. Then find a handy helper to elevate your planter so you can do the same. Please keep in mind, the overflow drain goes all the way to the top of the cone area. You should hit a hard surface as you poke, which is the inside wall of the double wall. Watch this video for a thorough review of the process.