hey guys need some help

hey guys i noticed this showing up on my plants today. its on all 5 plants to sum extent not sure exactly what it is so if anyone here could lend their 2 cents that would be greatly appreciated. temp high/low is 77/63 and RH high/low is 61/34

some of the stems look purple , are you feeding and what kind of soil ?

i don't thing purple branches of fan leaves is a big deal... could be wrong though... either way if your main stalk or any of your main stems have purple then it is probably magnesium deficiency.

My plants get a little purple when the temps drop into the low 60's. How long in the solo cups, might be time for a feeding is my first impression. I've never started in solo cups before though.. and not knowing much else of your grow. If that is starter it is definately time to feed. Seems like it would be the time to pot up? Nice babes for sure. Take care of them.

Purple stems I have had often, doesn't mean any problems. What I did notice were on one leaf a straight marking, almost like from a hot T-5 bulb may have touched it and a few brown spots like you may have something feeding on your plants' juices. Possibly a sucking insect.

thanks for the fast replies, to add a little more info they are 20 days old from seed started in jiffy peat pellets and moved into the solo cups with a 50/50 mix of fox farm ocean forest and a seedling mix of peat vermiculite and lime when there were 8 days old. so they've been in the solo cups for 12 days. and no i have not started feeding them but from the sounds of it it's time to pot up and start their feeding as well. didn't really realize how old they really where until i checked right now. boy do the weeks go by fast with a busy work schedule haha