first time grow

well the ladies have certainly come on a lot now, the tallest plant is 26 inches, the 5 plants are all different sizes the smallest being 10 inches! it was a late starter! ive moved the lights accordingly, I haven't fed them anything as I wasn't sure if the reason the stems were reddish purple is too much nutrients?, basically watering them all with just plain water, some leaves have brown spots on and the stems on 2 plants are like rhubarb stalks, having problems uploading the rest of the photos