Quote Originally Posted by irydyum
That definitely looks like underwatering. Plants use osmosis to transport water, kinda a spongelike effect, and if you have no water in the plant material, it can't keep itself rigid. Water asap and you should see the situation clear up before your eyes. Within 20-30 minutes.

How large are your containers? Does 1 litre of H2O allow for some runoff out the bottom of the container? I use 5 gallon containers and use approx 2L/watering and water every third day. Tiny amount of runoff. The day before I water the soil is usually dry and shrinking from the side of the container just a bit, but the plants never exhibit signs of thirst like in your picture.
yup, water water water