Athosanswered grow question 6 years ago That's called clawing, it's a sympton of excess nitrogen (over feeding) like the burnt tips that can also be seen on some of your pictures. Let the plant feed from the soil and stop feeding it for now. The purple stems could be due low temperature, try to get them above 23°C (73°F) or magnesium deficiency, but before rushing to buy anything, keep in mind that excess nutes can lockout minor elementos like magnesium. So stop feeding, rise temps and see how it goes.