Deficiencia desde la tercera semana de floracion

The 1st pic looks like magnesium deficiencies to me. The 2nd pics kinda looks like burning by also potassium issues. The 3rd pic looks like a root issues in the medium maybe caused by PH or rot. We need more information on how they are grown and what you are feeding them plus the data of your environment, temps, ph, ec, lighting schedule, lighting height, nutrients how much how often and brand. Best to start a diary and link it to the question. My ball bark guess if they are locking out things in the medium and getting overwatered as it lacks good drainage...maybe, but could be wrong, might need to correct this with a flush and some balanced feed and better watering practices. Good Luck!