Sad looking plants

3 litres is nowhere enough water for plants that size. Probably 7-10 litres would be more appropriate and every 3-5 days would be about what I would be giving them. Are you watering to run off? This is important with container plants as it is the only way to ensure the soil is moist from top to bottom and also helps prevent nutrient salts from building up to toxic levels. Also, since you are growing in textile pots, they will dry the soil out much more rapidly in windy weather, as the fabric acts a bit like a wick and literally sucks the moisture out of the soil. Hopes this helps,......... Organoman.

Looks like they are just taking a rest from a hard days work. I find my plants droop before sundown.