A blurb from the dispensary I go to:

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Cannabis is a perishable product. They are simply dried flowers, like many herbs. Some techniques can be employed to make them last. The three things to remember are C.A.L.

Cool.
Airtight
Light resistant

COOL - Storing at room temperature will cost you a heavy penalty in aroma and flavor from the cannabis' evaporating essential oils. The loss of these oils also likely lessen the effects of some strains that have pharmacologically active oils such as limonene. As for cannabinoid content at room temperature, you won't lose much, since THC degrades slowly over time into the less psychoactive CBN. At CRC we store all our cannabis in temperature controlled wine refrigerators at a temperature between 52 and 55 degrees F. A lignum-vitae temperature-controlled custom walk-in humidor would also work, if you're both rich and somewhat insane. If you're neither of those things... at home, the vegetable drawer of your refrigerator works very well.

AIRTIGHT - reduces oxidation and drying in your meds. However, it's important that you allow limited gas exchange, in other words, you need to vent the normal gases that accumulate in stored cannabis to keep it from going anerobic in storage. With very fresh meds that still require a little cure, this means opening the container a couple times a day. With well-cured meds, once every couple of days is fine.

LIGHT-RESISTANT - The biggest enemy of medicinal cannabis is ultraviolet rays from the sun, which quickly degrade THC and oils. Always store your meds in a light-resistant container.

One last note about plastics and glass as storage mediums. If you choose plastic, make certain that it is chemically-inert, like polypropylene, so that the plastic doesn't react with the terpenes and phenols found on cannabis. Some of these natural chemicals react with plastics to create formalin, the precursor to formaldehyde (embalming fluid). Don't store your meds in baggies or other soft, oily plastics. Glass is an excellent storage medium, but use dark amber or cobalt glass. The only drawback to glass is that it carries a static charge that can collect trichomes from cannabis. At CRC, we use opaque polypropylene containers for our patients and large glass containers for storage.

--morpheus
Cornerstone Research