Why are your temps and humidity so low plants look droopy and why you using low doses of Cyco Nutrients you should be using 8 ml per gallon by now should at least be in the 500-600 ppm range good nutrients if used correctly
@THESTONEDCHEF, The temperatures are in Celsius degrees not Kelvin. In Western Europe, right now, it's winter. So 20ยฐ Celsius doesn't seem low to me.
The indoor air is dry because of my heating method (wood) which produces a lot of dry air. The outside air is also dry because of the frosts in the morning. I would like it to be a little more wet but I can't help it.
Here the tap water here is already over 550ppm without any nutrients. More generally, with fertilizers it is easier to add than to remove. I don't trust much what the manufacturer, Cyco, recommends on its bottle.