How to prevent Black spots?

Thank you all for the reactions. Indeed I believe it are thrips as I searched some pictures of it on google. Fuck…. Not good. I will see what my local growshop sells to fight those insects.

I can see the larvae of the Californian thrips, use predatory mites as solution

omg... he's STILL removing his answer and putting it up top - Nugsery, take Ezzjaybruh's offer, man - you're embarrassing yourself!

Thrips. Mouse was correct from the get go. Nugsery - if you’re that desperate for seeds - DM me for fucks sake. I’ll send you twice as many as is in the 1st place prize if you remove yourself from this comp.

High Rootsman, the damage you see on the leaves is caused by bugs called thrips. You,ve got a huge infestation going on. When you look at the leaves you can see the small light orange bugs crawling on top of your leaves. You can kill them easily but you want to use organic methods to prevent unwanted products on your buds. Here is a link from the grow weed easy website with all the organic products and safe methods to kill thos f*ckers! https://www.growweedeasy.com/cannabis-plant-problems/thrips Goodluck!

Nugsery doing what he does best... deleting old WRONG answers and basically copying someone else's... At least I realized m0use had nailed it and I was wrong - and I admitted it! What a jackass....

Damn! I DO see the thrips now! M0use is entirely correct!

The black spots are a concern - but then so is the almost white frost you're getting first... I don't know exactly what's going on here but I would worry about some type of fungus that isn't good at all! You've got to get your humidity down as well as your temps and get your fans working quick time! ... and then I'd use an organic fungicide on the entire grow to prevent the spread... something like Dr Zymes Eliminator (my favorite) which will ALSO kill off insects such as spider mites, thrips, aphids, whiteflies in all stages of their life (but I don't see any indication here that you have an insect problem) - just mix as directed and spray just before lights out. If you can't get that wherever you live (you'd probably have to order it from Amazon - https://smile.amazon.com/Amazing-Doctor-Zymes-DZE1QT-Concentrate/dp/B07C8C2GLY/ - you can try other organic fungicides but they probably won't be as effective... Neem oil, for example, is (imho) pretty useless... But get the temps and the humidity (ESPECIALLY the humidity) down - temps in the 70s, humidity in the 40s to 50s.... Good luck!