To keep it fresh indefinitely, the best bet is buy a vacuum bagging machine. It sucks all the air out of the baggie and seals it. Then you keep your main supply in the freezer. Air, heat, and light degrades the weed. Every month take out one month's supply and keep it in a baggie that you squeeze the air out of after you open and close it and store it in a cool place, best is the fridge.