1st time grower with nutrient/sexing question

Hi all...I am attempting a grow with some bag seed...not expecting much, but figured it was a relatively cheap way to experiment...I germinated 10 seeds in Rapid Rooters, then transferred them to 2 gal pots with Fox Farm Ocean Forest/perlite mix...since then, they have been outside enjoying the natural weather...I have not added anything since, except for occasional watering if its not raining...they have been in their pots about 4 weeks or so...all have 3-4 sets of leaves, except 1, which never sprouted...my questions are:

When do I start adding nutrients, if at all...and if so, any recommendations as to what to use? Let's keep it store bought as I'm not going to mix shit up...follow up would be how often does one add nutes as things progress? Should I be checking anything like soil PH, etc?

Next topic is sexing...since these come from an unknown source, when can one tell sex?

Soil if fairly forgiving as far as pH is concerned as long as the water and nute pH is pretty close to neutral. If you are on the 4th set of leaves you could start nutrients pretty soon (the FF has an initial nute load in it that is probably nearing depletion at 3-4 weeks). Start with 1/2 strength and see how they react. Personally I use a Miracle Grow tomato food (18-18-21) and am fairly satisfied with the results, others are going to tell you it's horrible stuff but IME it's working well (and it's cheap). From my reading it seems that many cannabis specific nutes aren't that different from brand name garden nutes (with the exception of an inflated price tag).

Your plants should start to show sex in the next few weeks as they are a later start. All of my plants sex just after they start pushing out side branches.

EDIT-> I don't pH anything and I water straight from the tap with the hose / sprinkler.

Buy a General Organics Go-Box....start feeding now with 1/4 strength...next week go 1/2 strength.....then full strength......feed once a week, just water in between....You should NOT be using straight tap water, it contains chlorine. A bucket of tap water should sit in open air for 24 hours AND needs to be ph'd after addings nutes to it....Do yourself a favor and buy what you need now to properly ph your water/nute water before you kill your plants.

I start the nutes as soon as they get transplanted. I start very light, and work them up to heavy doses over a couple weeks.

ETA: I am also always using well water, or stream/river water, so ph has not been an issue for me....