When am i ready to put the rockwool cubes into the system???

Well I have 2 rockwool cubes with plants about 4 inches tall so far and looking very healthy! Pics soon. I just bought a drip hydro system and I dont know when my young ones will be ready to put into the net pots or even when theyre ready for nutrients. I anxious to hit them with the AN Sensi. I was upset to find out tho that my setup doesnt have an exterior control for the water pump, will it really not hurt the plant to have a constant flow of water to the roots?

Also, is lemon juice okay to use to lower pH???

Thanks for the help guys!!! Ill keep everyone posted on this one

are the roots comming through? if so then their ready to go into the system. just make sure the water level is right below ur netpods