I'm going to be growing with organic soil/perlite mix and organic nutes. Should I cover the soil mix with a layer of perlite or with something else to protect from it the light? I know this is done in hydro set-ups to stop algae etc what about in soil? Any thoughts appreciated!
The only reason you keep it covered in hydro is because of the moisture factor. You do not need to cover your soil.
No. It's not necessary. Sometimes it's done in hydro because the medium is wet all the time from the constant waterings. Soil is allowed to dry off some so those problems don't happen too often.
I'm on my first grow, I thought it was a good idea to cover the dirt to protect the roots. It was a bad idea. I used cardboard cut to fit the pots. I went home for thanksgiving and came back only to find what looked and acted like fungus gnats. Now i'm not blaming the cardboard completely, as I don't know where this little Fers came from, but the cardboard allowed the dirt to remain warm and moist too long. A perfect place for fungus gnats. I had to battle with them for a bit, eventually I won. But it did slow down the growth for about a week or two.