Need help , experienced only - how to turn plants purple or blue with night time temp

Ok , i have 3 plants ... (BLUE MYSTIC) by nirvana seeds , (BLUE MAGNUM) by nirvana seeds , (BIG GRAPEFRUIT) by female seeds.
I know the blue mystic and blue magnum are supposed to turn blueish and have blue hues and a blue shine , and the big grapefruit supposed to turn purple .. My question is how should i turn them their colors??? Like far as the night time temps?? And how many weeks should i have the in colder temps? Right now i have the in a steady 53-55 maybe 56 degrees for my night temps.. Is this right to turn them their colors??? Jus someone give me alot of info on this turning plants purple blue or watever color they turn , ect.. Thanks alot .. Please help asap....

You can turn any plant purple with colder temps...it's basically killing the chlorophyll and turning it purple. Now for strains that have that trait to turn purple naturally you want to drop your nighttime temps about 15-20 degrees of the daytime temps. And you should do it for the last 3 weeks of flowering and it'll purple those plants up nice.

I wouldn't drop my temps below 58. Any colder and your plants growth will slow drastically. Meaning less yield for a little purple. If purple is in the genetics they will turn usually the last 2 weeks of flower. I run 75 daytime and 58-60 nites. My kush strain ends up purple the last 2 weeks of flower. Good luck.

Purple means the plant is stressed. If you really want this put it in the fridge for an hour a day. It needs cold to frost to go purple unless its a purple strain.

I like to use food coloring to give my plants their dankness. All the colors in the rainbow! People buy that shit!