Leaf tips yellow going grey???

4 weeks into grow of lowryder 2, it's my first grow and the lower leaves are turning yellow to grey quickly at the tips??? please help, I want to take care of my 5 little girls.

maybe its because there isnt enough light getting to the bottom of the plant as long as your buds are fine i dont think it should be a problem if it is get some light down there good luck with your grow

Put up some pics of the plants heres a link that might help you!! http://www.kindgreenbuds.com/cannabis-grow-bible/plant-problems-and-how-to-solve-them.html