The cold air dumping sounds like an interesting concept. We should compare progress performance. I'm working the opposite concept of allowing my plant to 'cool' down during dark hours, emulating the natural outdoor environment. I've cut out the heat register in the grow room, but so far the coldest it's been has been 65*. During the lighted cycle, temps range from 72* - 78*. So far I haven't noticed any stretching, just the buds getting larger.
Sound's like somthing to look into oldskoool.Don't have the tools to start keeping records and still i am building my exhaust/intake system.Read about the cold air dumpig method in high time's,it was being used in a huge grow op.Then i saw it on line when i was reading about growing tropical plant's in green house's,I think thay were growing point setter's.We will have to copair notes brother...this cite rock's my brother's and sister's
The process of "dumping cold air" into the room durring the darkperiod WILL bring out any colors that the plant can turn to. For instance if it has a tendendcy to turn puple it will turn purple, and the same for plants that get black or blue. Telling you thats why I love the winter. COLORS COLORS COLORS!!!