my first grow, curling problem

hi i have a curling problem, it seems like the tips of the leaves are curling downwards and i think the problem is overwatering but i wanted to check with u guys maybe there's smth else going on..for my first time i chosed soil as a medium grow cause it s good for beginners, i have a 600w hps bulb in a cooled tube with proper ventilation and i have 5 feminezed cheese..they were growing just fine but 2 days ago the tips started to curl, now im 9 day of veging..i would appreciate a little in solving the problem

posting pics always helps a good deal.
What you describe does sound typical of overwatering though. If its your first grow, its a mistake often comitted. Also, along those lines, be very careful with whatever nutrients you use. There is such a thing as too much of a good thing. Best if you start off with 1/2 the dosage and see how that runs.
Let your soil dry out, thats important too.
Have fun at it. Thats important too

i havent been adding any nutrients yet, ph is around 6.8 - 7 and im using 2 types of soil, one is guanokalong and the other one is biocanna terra plus so what do u think?