Slow growth

Your temps are fine. Micro machine should give you a clue, they are not noted for their size! Kannabia themselves suggest 60-80cm maximum indoors. They also recommend 18/6 as optimum. Topping and/or defoliating will also slow growth notably, especially with autos and LST can also upset them. If your lights are up high to accommodate your White Widow, the younger plants could be growing slowly due to the reduced light intensity, or maybe a combination of all these factors. Hope this helps,........ Organoman.

Ph, nutrition and light distance. Would all be factors I would be looking at. In vegging nitrogen is key npk 3-1-2 ratio. In flowering it is 1-2-3. With autos you have to shift as stages change. Good luck and happy growing 🌲🌲🌲👊

Some plants do not take well to training, this could be one of those cases. I see no obvious nutrient issues, but check your pH anyway. Recalibrate first. Could also be an issue early on that led to a weak root system. A touch of humic acid like Diamond Nectar may help her along.

sh i pale and weak. temperature 28c is highest point keep it lower like 25c. check ur ph if its in range than add feeding to the watering she is starving