yellowing leaves

This is my 1st grow and I notice yellowing of lower leaves when flowering started. I used jumbo bud 0-56-30 in soiless compost.Being there is no nitrogen,I expect is causing the yellowing.What can I use to up the nitro quick.What causes green stems on leaves to turn red,purple brown.Is it normal or a sign of something.Thanks for your help. Showgirl

im not to sure but if you wanna up the nitro you could try Milorganite 6-2-0 Organic Nitrogen Fertilizer its like 10 bucks in a gardening store. but im growing plants and they started to yellow on a few leafs i think its because of lack of light or not enough water or the water ain't good for the plants. hope that helped.

From your problem it sounds like you have a Nitrogen defficiency, try using some plant food spikes with a 12-3-2 NPK ratio, and see if that works for you. Best of luck.