By day 17, the seedling has developed 4 sets of leaves and has a wing span of 2.5 inches. It has a healthy green color. On day 20, I am giving the seedlings small amount of nutrients (including CalMag) for the first time. I am only giving them 1/4 of the recommended dose to avoid initial nute burn. The plants have grown an inch this week. Their stalks are quite thin, so I have propped some of them with thin wooden skewers to support them till they get a bit stronger. I am introducing a fan blowing at them few hours a day to hopefully make them stronger.