Some stems turning purple, should I be worried?

[Dirtymuckel]

Hey folks just noticed some purple in the stems of my plant and I’m wondering is it anything to be concerned about, I know some genetics turn those colours themselves but I’m not really into full flowering yet and this is happening so screams a nutrient problem to me although it’s not happening in the leaves of the plant there are some early leaves of the plant that have turned brown and yellow although I do think that is natural. A second opinion would be greatly appreciated as I’m still a noob at this lol. For a bit of background info the plant is around 11-12 weeks old and is being watered every 2 days or when the soil gets dry. The plant is in a 10litre pot and is getting 4-6 litres of water with 12ml of old timer organic veg nutrients putting 3ml of nutrients int every litre of water. I don’t know the PH of the soil but the ph of the water going in is at 7.2

I’ve posted some photos down below one of the full plant so you can have a look at the rest of the leaves I guess but the discoloured leaves are ones from really early in the plants life not sure if that should concern me but the purple in the stems is defo starting to. Thanks again to whoever replies

 

[Jack og]

In flower they need more nPk the P, phosphorus for root development and nodes, so it’s why when u lean off veg, the flowering nutes have a higher pk value, I wouldn’t be too worried if thr nute line has enough pk if not get some that does