Weed doesn’t go bad the way a jar of mayo or some other food product might, but it can definitely be “off” or even moldy.
Old weed likely won’t lead to any serious health issues if you don’t have any underlying conditions.
It can, however, have a noticeable drop in potency, which can be a big deal if you’re using it for medical purposes. Older weed can also undergo changes in taste and texture.
When stored properly (more on this later), dried cannabis keeps for 6 months to 1 year. Over time, it begins to lose its aroma and potency.
According to some older research, weed loses roughly 16 percent of its THC after 1 year, and it just keeps dropping from there:
- 26 percent THC lost after 2 years
- 34 percent THC lost after 3 years
- 41 percent THC lost after 4 years
It’s mostly in the smell. Weed that’s past its prime will smell different or lose its aroma entirely. Some weed might even smell and taste harsh when it’s been sitting too long.
Its appearance can also give you a clue as to whether or not it’s old. Fresh weed shouldn’t crumble or feel spongy when you break it off. If it does, it’s old and either too dry or too moist.
Consuming it shouldn’t harm you, but be prepared for changes in texture and potency. The exception is weed that’s grown mold, which could potentially make you sick.
Mold is often hard to see unless you look very closely. It typically looks like white powdery or fuzzy spots, some of which can be pretty small.
Moldy weed usually smells musty, kind of like hay. It also tends to have a bit of an “off” taste.
Even if your weed isn’t super old, it’s best to do a mold inspection. A study by researchers from University of California, Davis found bacteria and mold on 20 cannabis samples bought from dispensaries and pot growers in Northern California.
Mold on weed isn’t likely to cause major health problems, but it can lead to nausea, vomiting, and coughing.
In people with weakened immune systems, inhaling smoke or vapors from weed containing bacteria or fungi could cause serious illness or even death.
If it looks or smells off, then you’re better off tossing it, even if you just bought it.
Light, humidity, temperature, and oxygen can all mess with cannabis and affect its aroma, taste, and potency potential.
Here’s what to consider when storing weed to help keep it fresh and maintain its quality for as long as possible.
Choose the right container
Ditch plastic baggies and containers. Plastic holds static that can affect delicate trichomes — the tiny, crystal-like hairs on flowers that produce cannabinoids and terpenes — and mess with potency.
And forget those funny little tins, too, because they let in too much oxygen.
Glass jars with an airtight seal, like mason jars, are the way to go. They don’t have any static charge and limit oxygen exposure. Plus, they’re inexpensive and easy to find.
Most dispensaries also sell containers designed to keep weed fresh for as long as possible.
If you have kids or pets in your household, invest in a child- and pet-proof container.
Watch the humidity
Weed is best kept at a relative humidity of 59 to 63 percent. Any higher and you run the risk of trapping moisture, which can lead to the growth of mold. Anything lower can cause your weed to dry out.
To help you preserve your stash, you can add humidity packs to your containers if you really want to get fancy. You can also go the extra mile and store your weed in a humidor made specifically for cannabis.
Keep it cool, dark, and dry
Keeping weed in a cool and dry spot away from sunlight is as important as the container you use, if not more so.
Direct sunlight can cause cannabis to break down, and too much heat can hold moisture and lead to mold.
Keeping it somewhere too chilly, on the other hand, could dry it out and lose those precious trichomes, which is why the fridge and freezer aren’t recommended.
Aim to store cannabis in a dark place, like a closet or cabinet, with a temperature below 77°F (25°C).
Everything lasts longer in the freezer, right? Not quite.
Freezing temps can cause trichomes — the tiny hairs on flowers that produce cannabinoids — to become brittle and break off when handled.
Keeping weed in the freezer can also expose it to moisture and result in mold.
Weed shouldn’t go bad if you store it properly. By keeping it in a sealed container away from heat, moisture, and sunlight, it should stay fresh and potent for up to a year.
Adrienne Santos-Longhurst is a freelance writer and author who has written extensively on all things health and lifestyle for more than a decade. When she’s not holed-up in her writing shed researching an article or off interviewing health professionals, she can be found frolicking around her beach town with husband and dogs in tow or splashing about the lake trying to master the stand-up paddle board.