Putting ice on your soil before harvest?

Someone told me that if I put some ice cubes on top of my soil 24 hours before harvest, it'll make the plant think winter is coming and it's going to die, thus it quickly produces more resin.

Is this true at all? I have a plant starting to turn purple and I want to encourage the purple... was thinking this might help.

Dont use ice cubes on the soil, thats TOO cold. Thatll kill the plant. If you want to encourage purple, bring your nighttime temps under 65. No colder than 55 though.