How long does it take for my plants to start turni...

My purple varieties usually started to change colors around the 3rd-4th week of flowering...as soon as my pistils slowly started to discolor the sugar leaves etc. Began to start showing their reds and purples.

Temperature will influence this factor if it's in the genetics. Lower night time temps of 10-15max lower then daytime temperature will accelerate this process called anthocyanin accumulation which causes anthocyanin to build up within plants. While chlorophyll is what gives weed and plants in general their green color, anthocyanin is what makes weed purple, and carotenoid is what will make weed yellow or gold. I'm late on your question but now you know. Cheers mate.

My Dark Devil autos started getting purple leaves and showing purple pistils around 4 week of light.

hey there race91, so for the blackberry , it should be turning pretty soon , check out @rastafari 's black berry, his started turning pretty quickly around the second week of flower already. You'll see a sort of "shiver" run through the plant and the color start to bleed out of the buds onto the leaves. Every plant is a bit different though, for example dark devil turns towards the end of the flowering period. The purple punch you have i dont really know, but my FBT5 (suspected purple punch) is already turning on week 1 of flowering. As you know it's all about the day/night temperature difference and to a certain extent it's about the root zone temperature. As you said you can't really do much about the night/day temp difference, what you can do is use blocks of ice to water the plants the last week or 10 days to force the plant to show colors. @wheedtobeus - she uses that technique to great effect . Hope this helps ! 🚀

Hi , I had last year 4 wonderful dark devils, they were different in colour from pink to nearly black, they showed it in late 8th week, they were harvested from week 10-12. it was a lovely grow. Nice choiche.. happy growing

It's differnet to say. It depends on genetics and phenotype. I had two purple bud autos one turned purple at week 6 the other one never really looked purple only when I first grind the buds I could see it. Maybe yours will show soon when the buds get bigger. Good luck!

This typically happens in the middle to end of flowering . It has a lot to do with temps as well . Generally speaking at the end of flower usually the temps are alot cooler like a 10 degree difference between night and day this generally makes the plant gain a lot more colour it also has alot to do with strain , if your strain isn't a "purple" strain then your likely not going to get any major purple unless your force the 10 degree difference . But over all to answer your question in a simple way in the middle to end of flowering is when this usually starts to happen . I hope the information provided helps you understand the when and they how that makes a plant gain colour during growth . -Happy Growing!