Bonsai grow

I was going to top the plant today but I think I'm going to give it a few more days. I plan on cutting it just above the second nood when I do so I want to make sure that there is a fair amout of growth there before I do that to make sure there is enough plant there to keep the plant growing, rite now there isn't much and I'm worried that it might end up killing the plant. I've finding the plant is growing slower then the rest when it comes to lower growth, not sure if that's from the light or because of the pot I have it in. Im leaning more towards it being the light because i noticed a bit of light bleaching on one of the upper leaves the other day. Going to have to brake out my PPFD meter and test it. Shouldn't be much more then 600, the 50W light AeroGarden uses in there units isn't very powerful. Well that's all for now so happy growing everyone!!!!