AquaPots® Lite Large Insert - RoundNow, many containers can be self watering AquaPots! The AquaPots Lite Large Insert works in conjunction with AquaPots Lite and many existing containers to make them self watering. The 18 insert holds 6. 8 gallons of water and fits round containers with a drainage hole. Simply set the insert down into a large upright container. Consistent moisture from the AquaPots helps keep plants healthy and thriving all season! The large round insert is 18in. 18in.