cold air and light. thats what purples down a plant. its all about the cold nights and sunny days. good luck!

yuuuuup, during flowering

yup.. that brings out the colours really nice.. sunny days and cold nights!..

In my personal experience, putting fresh weed in the freezer destroys the goodness of it. You can still smoke it eventually and it might be alright.. but it looks alot worse and wont be half as good.. Lol it will make it a tad bit darker looking though. but its crappy.

never herd of chaning the colour afterward of growing,,,,,,

this was brought up at the cannnabis cup by arjan of green house seeds. this done after the weed is dried than put in the freezer for 6 weeks .not sure on the whole idea but is supposed to bring out the terpes in the bud.

What if I put my plants in the fridge at night near the end of flower?

that could work. is this a purple strain? or are you just trying to purple the leaves? i have also heard of growers cutting off the lights for 48-72hrs and blasting AC. cold will purple the leaves real good, but for a purple strain to show purple you need both good light and cold nights. Oaksterdam says that purple strains thrive under 1000w and love to be fed with every watering. i have also found this to be very true. my strain loves the light and the nutes. i can hit em with all i got and they just love it.

Lol <Im sure it would work. Nighttime they dont need any air, if your fridge is big enough, try it out.. probably be a good test.. apparently colder temps at night sometimes boosts crystal coverage too since the plant feels its time to shut down and protect itself or something.. worth a go for sure.

I have a couple purple indicas and a blueberry flowering right now that I will try it on. what week should I start putting them in there?

They actually do need fresh air 24/7 just as do you. Air has Co2, which the plants take Carbon from to make their bodies. And if your fridge is "too cold' which means below 50 F ,which it is, your plants won't do so well, between the temps and suffocation.