Answer these simple questions the best you can.
If you do not know, or do not use something; Just say so = NA
Strain; Type, Bag seed, or NA
Soil in pots, Hydroponic, or Coco?
PH of runoff or solution in reservoir?
What is strength of nutrient mix? EC, or TDS
Indoor or Outdoor
Light system, size?
Temps; Day, Night
Humidity; Day, Night
Ventilation system; Yes, No, Size
AC, Humidifier, De-humidifier,
Co2; Yes, No
Add anything else you feel would help us give you a most informed answer. Feel free to elaborate, but short, to the point questions and facts will help us help you smile
There are multiple issues which could result in purpling of stems. Genetics, low temp, phosphorus deficiency, nitrogen causing nutrient lockout, pH causing lockout, etc…
This quick questionnaire will help us determine which issue is most likely.
The “sweet spot” for soil pH is 6.5, for Hydro and coco (soiless) is 5.8. You do have a +/-0.5 swing for each, but that will affect different nutrient uptake. For example I run my soil grows closer to 6.5 in growth stage and 6.2 in flower. Where as I keep coco closer to 5.9 in growth and 6.1 in flower.