Hello, for this grow I decided to make a mix of soil and coco (20L) But they are drinking less quickly than during the previous grows. (1 liter less). Humidity 50% and temperature 25°C. Should I change the watering frequency?
Your soil is a chance of getting water logged with that particular mixture thus staying wetter for longer . Coco chips or perlite mixed through works well before you plant but obviously you are well into your grow so transplant might be detrimental to your goals , you could drill some extra drain holes in the bottom and sides of the pot to get some drainage going faster or consider a transplant into a better draining medium .
If your medium is drying up quicker then increase your watering frequency and amount. If its taking a while to dry then less frequent but put more water through them.