Heat stress?light burn? Nutrients deficiency?

Nope... not heat stress or light burn - that would be showing up only at the very top of the plant if it was too close to the light... This is a nute burn of some type - but without a diary, can't give you any more than that... sorry! Good luck....

I don't think so, they don't seem to have suffered from heat stress. I think it might be another problem, such as nutrient burn or some defficiency.

Hi i would say it looks like some sort of effect from over feeding, I would give it a good flush for a couple of days and then feed again will a less dose and see how she goes, Good luck bro 🌱

Si sembra una bruciatura da potassio e fosforo o nutrimenti in generale....ti saprò dire meglio se mi dici come la nutri e che marca usi...magari mi dici anche i gradi che hai e con che frequenza innaffi le tue piante! Quoto già la bruciatura per nutrimenti ma se mi dici il resto forse posso aiutarti ancora di più!