What strain of DP are you growing mate and how many?Looking really good red I'm a couple of wks ahead of you mixture of Dutch passion for me, but mine are all very short which I'm putting down to having to many led's in the tent 1600w Mars ll per square meter bit of over kill but im a believer more light is better lol
Do you only have the one light?You may need a less powerful light for veg to encourage a bit of stretch.
Have you got any pics?