Markings on leaves

Sarà un bruciatura di nutrienti ti consiglio di fare qualche lavaggio finché non si riprende altrimenti non vivrà ancora a lungo

@ORGANOMAN spreading has stopped but the looks of it and hopefully it has. I dont use any humidifier as my humidity avg around 50%-55% throughout which I think is ideal. Ive stopped foliar as i think it contributes. Markings started to show when I started foliar in the evening so..since spreading has stopped as I stopped foliar it’s possible.

@TheHappyClique I started light nutes at week2 which is really recent. I doubt its burns cos other seedling is fine and this doesn’t look like burns either. Just not sure what it is

@Cannabis_chris humidity is averaging at 50% whether lights are on or off. I water everything morning not long after lights go on. I do foliar spray in the evening but I stopped it thinking that contributes.

Have you given her nutes ?

To me it looks like a fungal problem, most likely caused by having bottles/humidity domes over your seedlings while young. I would be chopping those leaves off before it spreads and switching off any humidifier if you are using one and/or generally reducing the humidity in general. Cannabis actually prefers a dry climate and does not need artificially high humidity, it is an outdated concept from when people thought cannabis grew in rain forests, from 50 years ago, when they knew very little true facts relating to cannabis. Most Indicas come from places like Afghanistan, Pakistan, Morocco and other places in the middle east, hardly any humidity in those areas, just the opposite, very dry. Most Sativas are from lowland areas in the tropics and grow during the "dry season", again, with very low humidity. Hope this helps,.......... Organoman.

I would recommend picking up a copy of Ed Rosenthal's Grower's Handbook as well, great quick resource to have to go along with this site's community

What's your humidity? This looks more like mildew than cal-mag to me. When are you watering, and what is your humidity when the lights are off?

@aussiegrower yes light calmag+grow has been introduced at week2. Coco has been buffered with calmag too. Im still giving calmag since its coco. Other seedling is fine so il not sure whats up.

Have you used calmag in the coco or when watering?