If you have some experience with cannabis consumption, you’ve probably found yourself in a situation where you found an old stash in the back of a drawer and wondered “is this weed any good?”

Despite the popularity of cannabis products and smoking devices, like weed vapes, many people aren’t sure where to turn for reliable answers when it comes to this type of specific cannabis question. 

To help you get the good buds, without the stems and the seeds, we’ve prepared this guide to answer your questions about the shelf life of dried cannabis and what to do if you come across some weed of unknown age.

Before going into the details of ideal storage, it is worth noting that in order for cannabis to stay fresh as long as possible, it has to be properly harvested, dried and cured.  If you get your supply from a regulated source, this shouldn’t be much of an issue, but it’s a case of “buyer beware” if you get your buds from some other less reputable source. 

Under ideal storage conditions, weed can stay fresh and tasty for up to two years. But most people won’t have precision climate controls where they keep their stash, so their weed won’t last nearly as long. 

If you can store your stash in a relatively dry and dark environment, your weed can stay fresh for up to six months. But if all your weed doesn’t get put to use within that time frame, don’t worry. Older weed will still produce some effect, but it won’t be as nearly as tasty and flavourful as it was in its prime.

Yes, it can. If your pot shows any signs of mold, don’t smoke it! 

Things to look out for include discoloration, fuzzy growths and odours you don’t normally get with cannabis. Any (or all) of these indicators point to the presence of mold, which should not be ingested in any way. Mold exposure can make you sick and potentially leads to all kinds of unpleasant symptoms, as well as probably killing your high. 

Unless there are signs of mold, old marijuana can still produce effects and be safely smoked without putting your health at risk. Signs that weed has passed its best before date include a total lack of humidity and a weak scent. 

If your buds crumble into dust when you touch them, that’s a sign that it has become too dry with age. Also, if your stash doesn’t smell much like weed, that’s another sign that father time caught up with it, so you should probably turn the page and get a fresh bag.

Instead of going through a list of some of the latest stoner theories that exist online, the best way to separate truth from fiction when it comes to cannabis news and information is to see what scientists have to say. Fortunately, research in this area has come a long way, so we have a pretty solid answer about how the chemical compounds in cannabis change over time. 

In a study for the United Nations Office on Drugs and Crime, researchers looked how the tetrahydrocannabinol (THC) and cannabinol (CBN) found in stored, dried cannabis changes over time. 

This study was carried out with the scientific rigour fit for an academic journal. The researchers packed and stored several strains of dried cannabis in order to check their THC content periodically over time, to confirm (or deny), the widely held suspicion that weed gets weaker as it ages. 

Their findings confirm that sneaking suspicion you’ve had. It’s true, weed weakens over time. This study found that “the percentage loss of THC was proportional to the storage time” and that the concentration level declines at a predictable rate, with some variation. 

On average, the THC levels of their stored samples fell by:

• ~17% after one year
• ~28% after two years
• ~35% after three years
• ~41% after four years. 

So, what does this mean for your average cannabis consumer? Even under ideal storage conditions, cannabis plant material loses its potency over time.

To keep your weed as fresh as possible for as long as possible, you need to keep a few factors in mind. The more exposure your weed has to the environment, the more it will deteriorate. Controlling temperature and humidity levels, as well as limiting exposure to light and air, are they keys to keeping your weed fresh for six months or longer. 

Sorting out a proper storage location to help keep your weed fresh is one of the best ways to make sure you have a consistently pleasant cannabis experience. 

IDEAL CONDITIONS FOR STORING CANNABIS

Cannabis products should always be stored in a cool, dry place. 

As with any other organic material, weed can be a breeding ground for mold and mildew, which is why controlling humidity levels is so important, especially for long-term storage. Molds thrive in relatively warm conditions (77-86°F or 25-30°C). Also, lower temperatures slow the breakdown of cannabinoids, so keep your stored weed below that temperature range. 

In practice, weed is best stored in an airtight container, like a glass mason jar, that is kept in a cool, dark place. If you keep the lid on tight and don’t open it too often, your weed will stay fresh for months and months. 

Because of the variety of factors that influence how long weed lasts, it’s impossible to say exactly how long you have before your stash will go bad, but it’s safe to say that, when stored properly, weed lasts for months.