Hojas amarillas 3 semana flora

You don't have any information on nutrients you're giving her - but at this stage of their growth, they want a lot of P and K - not so much nitrogen! The nitrogen, if given too much, will cause a lockout of calcium and phosphorus and other essential micronutrients. You'd want to reduce the nitrogen you're giving and punch up the P and K.... if you haven't been giving any nutrients, then yes, a small amount of nitrogen will also be essential... I would get them on a good routine of a decent cannabis nutrient - a little bit of the grow nutes and more bloom nutes... Good luck!