AquaPots® Lite Insert with Adapter (Square)Now, many containers can be self watering AquaPots! The AquaPots Insert works in conjunction with AquaPots Lite and many existing containers to make them self watering. The 14. 37 insert holds 2. 9 gallons of water and fits square containers with a drainage hole. Simply set the insert down into a 16 20" upright container. Consistent moisture from the AquaPots helps keep plants healthy and thriving all season! The square insert is 14. 37in. 14. 37in.