Mosaic pale discolouration of older leaves

Thank you very much for help! Dr Zymes is not available here, so I ordered neem oil. I also put yellow stickers around plants.

You've nailed it - it's either thrips or mites but in either case, using some Dr. Zymes Eliminator will solve your problem. This is an organic solution and can be used all the way through to the day of harvest if need be. In my experience, neem oil is not very effective and certainly cannot be used when your plant gets into flower (and thrips have a way of coming back and coming back and coming back). I've had the same problem and after the initial 3 days of spraying, am now spraying all my plants once a week as a preventative. Works very well. You won't get rid of their markings but they won't be doing further damage to your plant! Good luck!

Dr. Zymes Eliminator is a expansive way to use citric acid, that's the only ingredient.

Thrips are tiny. Like, super tiny. I suggest BT spray. It's organic, won't hurt your plant in any way, and will take out anything that is taking bites out of your plant. Then, it dies a few days later. I hope this helps. Good luck! I hate having to deal with pests.

Fairly certain that’s a sucking insect - I assume you looked under the leaves but if not, do that. I’ve had that too where you don’t see insects and I think it’s because they’re from tiny flies that are more mobile.

I am giving no nutrients yet. But the All-mix soil from Bio-Bizz is heavily pre-fertilized

My tip, A plant as young as this should not get feeded by nutrients but by light. Most of the time i start since week 4.