You can use the water level indicating float to monitor the overall water level. When the float hits the bottom of the tank and you can no longer bob it up and down with your finger, it's time to refill the tank. On average, a full water tank lasts for about 2 weeks, depending on the plants and their current growth stage, but you can definitely fill up the tank sooner if necessary. We do not recommend leaving the Smart Garden unattended for longer than a week to avoid any unfortunate surprises!
The Smart Garden 3 needs about 1.3 l/44 oz of water.
The Smart Garden 9 needs about 4 l/135 oz of water.
Make sure the water level indicator doesn't rise above the surface of the lid to avoid overwatering.