Darkness

so whats the deal with the 24-48 hour darkness before harvest time

There's a school of thought that light breaks down THC. The "fact" behind this is that the trichomes themselves act as the plant's natural UVB light filter (as UVB is damaging to plants as well). There used to be a really good video on the subject on youtube... but has been removed long ago that actually showed you microscopically how the glandular cells acted in the presence of UV light. The reasoning behind leaving your plants in the dark before you chop is that the trichomes produce THC- which will get broken down somewhat by the next day's light (not all of it.. but a small percentage) and that everyday the THC content is a little higher than the last due to this compensation from the plant's production of it. A plant will adapt quickly to environmental changes.. but it usually takes a few days for a plant to "realize" it has to adapt... so if you leave it in the dark for a few days (I think 72 hours is what most people say is good) they claim that (with a bit of science to back them) the THC won't break down as there is no light, but the plant will keep cranking out the THC as it's natural defence against the light.. so you will have higher THC content. I have tried this.. but didn't notice a difference in the end smoke myself. Give it a try with one of your plants and keep it separate when you cut, dry and cure it. compare the smoke yourself and see what you think. I didn't notice any difference personally.. but there is some reason to believe it does. I haven't read any results from a lab study on it, so it's still a fairly heavily debated subject on the forums between growers who say it's bunk, and growers who swear by it.