when can i start adding nutrients in with my watering? three weeks in

i had these going for like three weeks now and wanted to know when is it safe to start adding nutes?they have only seen plain water. im using floranova it is one bottle for veg and one bottle for flowering. i wanted to know is it safe to start using this at 1/4 strength? and should i water with nutes from here on out or should i hit with plain water every now and then to give them a little flush or would nutrients be safe to use everytime from here on out? any info would be a big help thanks.im using hydroton with rockwool starter blocks hand watering once every 38 to 40 hours they seem to be doing well its my first time with hydroton so any info will be great.

how many true leaves? are you indoors or out

the third set is there /indoor thanks for the quick response

you should be fine to start now. I ran a little over three weeks in ff happy frog soil and the plants started to show a little yellowing around week 3. Once you start feeding give a 1/4 strength, which Im sure will do fine, then go up from there. As for how often: I do feed,water,feed. Some do feed,water,water, feed. It depends on the plant and how on top of your p.h. you are. If your p.h is right, you can stuff them with food like a lazy american.

lol thanks odessa how long do i use 1/4 strength before i step it up? i will prob try feed water feed it just sounds right. another thing i noticed is that everybody that uses hydroton waters like 3 or four times and some times more. i only water like once every 40 hours right now they are still little but the pellets seem to stay moist with my set up .do you think thats ok or am i underwatering. to me they seem ok. but if everybody else is doing something diff. am i doing it wrong?

I don't know anything about hydro cause I do soil. If after the the 1/4 strength they dont yellow at the tips and the plant looks right (turgid leaves etc) then it's safe to move up. I started at 1/2 and moved right up to full. My plants are pigs though, so ymmv.

ok thanks a lot odessa

I do hydro in rockwoll cubes and feed them 2 to 3 times a day. This chart I use and it seems to work pritty good, no problems yet.
PPM for Hanna Chart PPM

Seedlings, Early Sprouts 100 to 250
Early Vegging 300 to 400
Full Vegetation 450 to 700
Early Blooming 750 to 950
Full Mature Blooms 1000 to 1600

is this R/o? ppm or with the tap water ppm