Hello, I would like to know what are the reasons b...

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If you'd like to know what the reasons for this are, we'd need some information - and you have no diary. You THINK you know what the answer is because you give us a few pieces of info (you ask about water, humidity) but there are so many other factors that go into a grow.... I think it's probably a problem with either the nutes or the pH... but I don't know what you're feeding them, how much, what your pH is... or even what you're growing! Is it a photo? And auto? What's the substrate? To answer your question about how much water to give in 24 hours - well, we'd need to know what the substrate is first of all.... but secondly, your PLANT will tell you how much it needs. If you're growing in soil or coco, lift the pot up. If it's super lightweight, it will need some water or nutes (assuming you're following the water/feed/water/feed routine). When you give it plain water, give it enough pH'd water so that 10-20% of it runs out the bottom... and then let it dry so the pot is again lightweight before giving it nutes. Plants will drink different amounts of water based on their age and what stage they're in... they'll drink massive amounts during flower and then stop drinking a lot when they're getting ready for harvest... Soil is also very different from the water needs of growing in coco... So start a diary. Reconstruct as much of the past couple of weeks as you possibly can... no diary = no information. Good luck.