What do you think I did wrong? Overwatering? No fa...

Ok ehm... All😱 But you are right, you are here to improve your skills! So, first: under watered, one of them had the leaves down all over the vegetative stage, the other suffered on the roots (yellow leaves with red stems) for the same problem. Remember that is better to have a soil always wet(without over watering) where roots can grow everywhere, watering when the first 1-2cm of soil dry Second: temperature! 13 Celsius?too cold they need at least 18-24 during vegetative, better 22-26, and during flower 16/18-20/24 depending on weeks and genetics. Remember they are plants that grow from sea level to 2000m without problem. And the fan, always on! Not directly on the plant the first 2-3 week. For the next time try this: Lamp at 30cm from canopy always if you can dimmable It, otherwise change height 18-24 good range Pre fert soil (light mix) using only root juice first 2 week and One fert before flower (maybe more) Fan always on, oscillating better Soil always wet