To me it looks like your pH might be off. Slow/ceased growth is usually a tell-tale sign of a nutrient lock of some sort.

What method are you using to test the pH? If it's a liquid kit, it might be skewed due to particulates in the water sample. Those cheap pH pens that you stick into the soil are notoriously shitty, bluntly put. If you're using one of these methods, I would suggest investing in a nice pH pen (one with an electrode); a little expensive, but pays for itself in the long run.
purpleskunk777 Reviewed by purpleskunk777 on . 6 weeks in, only 4 inches tall Hi everyone, first time poster and grower here. I have two different seeds planted (rocklock/lemonskunk) and they are both having the same problems. These guys sprouted about 6 weeks ago and seemed to be growing well (albeit somewhat slowly) under CFLs for the first two weeks. Then I added a 150w HPS. I had about 6 leaf sets on each plant, but eventually the tips started drying up and dying, at the same time the plant just stopped growing. It did this for about 2 and half weeks. About a week Rating: 5