Stonerdanswered grow question 4 years ago Looking good but your plant shows some heavy Nitrogen (N) abundance and some slight Phosphorous (P) deficiency! - Dark green foliage indicates Nitrogen abundance which can easily lead to toxicity and will affect yield, taste, and smell of the bud. The weak purpling stems are a sign of early Phosphorous deficiency and only needs a slight adjustment (about 10-20% increase in dosage).
As for the slow growth it may be an inferior genetic seed which could cause stunted growth and low yield, another option was simply due to environmental/nutritional stresses! Make sure the climate is stable with enough heat during both day and night cycles (more than 6-8 degrees Celsius difference between day and night will start to harm plant growth), make sure watering is enough with at least 20-30% runoff, check the pH before every irrigation and in the runoff (should be the same).
Did the plant suffer toxicities or deficiencies before? those could affect future growth.
Hope this helps! Good luck and happy growing :)