Right, so I go back to this post of mine.
Hello everyone, after three years wanting to start to grow my own cannabis and lurking many boards so I can smoke some good shit (tbrazilian brick weed is just sad lol) I'm finally able to begin. My setup is the following Lights: 2x Citizen Clu048 running at 1500mA each (110w total) spectrum...
www.420magazine.com
If you say the plant is yellowing then it's hungry. It's hard to tell in the pic because of the lighting but some pics with the lights off and a flash or even room lights would help.
Cannabis is a demandful plant. It needs nutes when it calls for them(Mg and Ca recently and now N) and not when the roots find it. Organic growers spend lots of time cooking their soils and they still need to add teas and what not to keep things going. The plant is growing fast and probably about to start flowering so it's going to want a bunch of K soon and if your soil can't provide that then the plant could suffer.