With the clay granules and the urban Chili tub you only need to water once a week.
The clay granules act as a membrane between soil and water, therefore, can also be given 5 liters of water. A short break is thus easily possible. And the growbox just keeps going.
Best in the pot 1 piece of kitchen roll so that the clay grains do not fall out. Divide the delivered sack of clay granules evenly on all 4 pots.
Give earth on it, and you’re done. This creates the above-mentioned water membrane.
The 5 liter trick can only work if the plants are as high as the pot is high.