I live in the midwest where I can my veggies from my vegetable garden. The process beeblebrox is talking about is what I do. I know that fruit, veggies, and meat will last forever once it's canned. I keep my canned items in my tornado shelter, something like a basement, where it's cool. If you do this, your weed will last forever. As for another idea, get yourself a lock box and put your weed inside. Bury it in your yard, I've done this before, and after several months my weed was still moist and fresh. (Not mildewed).