Nutrients??

maybe too much water. let it dry well.

As far as nutrients, it looks like you may need some magnesium to fix the Purple stems ( unless it's genetics ) so if you have it use some cal-mag and also be careful not to over water your girls. They are very sensitive early on, a good trick for the first few weeks is to use a squeeze water bottle and use that to draw a circle around the plant about 6 inches from the main stem ( root ball ) this way it'll force the plant to search for the water and in turn it'll grow a solid root system. Obviously make sure the soil is fully saturated the first time you plant your seeds or in your case since they are already planted and the soil is saturated enough, I'd let her dry out a little , then draw a circle of cal mag/water and she should rebound!! Good luck Growmie!