I have about 30 50 liter cloth (geotextil) pots that I have been using for a garden on a terrace in the middle of the city and this was my attempt at watermelons.
Pretty much every day. The sun is strong during the summer and temperatures are regularly 30-33-35C for weeks.
The cloth pots loose a lot of water daily, even with a thick layer of mulch. They are convenient though as they are easy to move and stack during the winter.