Can Weed Go Bad Or Expire?


We’ve all been there: you’re innocently doing your spring cleaning when you stumble across a stash of old weed you forgot about, and you think to yourself, “can weed go bad?” 

Well, it depends on what you consider “bad”, and it depends on whether or not it is stored properly. You could still technically smoke it, but it wouldn’t smell, taste, or provide the same experience as if it was fresh. But before we get in too deep, let’s go over the science about what happens to weed over time, and if your particular stash is safe to smoke or not. 

Can Weed Go Bad?

While it doesn’t go bad or curdle like milk or bananas — it does get moldy or have an off or stale taste and smell. 

Unlike marijuana, food goes bad when bacteria and other microorganisms set up shop and decompose, releasing awful smelling gasses left behind in its wake. Since dried and cured weed doesn’t allow an environment where microorganisms can reproduce, it doesn’t go bad in the conventional sense. 

So, if you happen to have a properly stored container of old weed laying around in a dark place, it would be ok to smoke. But not great. 

If stored properly in a cool, dark, and dry place,  weed can keep for up to 1 year. After that, it starts to lose its potency and smell. According to the research, THC levels decline by 16 percent every year. That means if it’s been hanging out on the top shelf of your closet for four years, it’s lost around 41 percent of its THC. 

Besides, the potency and THC levels drastically degrade over time, weed also changes in texture and taste, which are automatic deal-breakers for so many cannabis enthusiasts. 

Especially if you live in a cannabis-friendly country — it makes so much more sense to toss it out and buy some fresh buds

Risks and Dangers of Weed Gone Bad

Can Weed Go Bad

It’s always good practice to inspect your weed before you toke up, even if it’s fresh. 

Did you know that a study conducted from the University of California, Davis found mold and bacteria on 20 different samples from different growers and dispensaries across Northern California? 

Yep. So make sure to check your stash, and this goes double for older weed.

Mold can be hard to spot if you’re not looking close enough, and while it likely won’t lead to major health issues, inhaling it can cause coughing, nausea, and vomiting.  

If it smells or looks off, we think it’s best just to throw it away to avoid risks. Since mold can be hard to see, you need to make sure you’re thorough and look it over slowly and closely. 

Weed mold looks like a fuzzy white powder, which can be hard to detect with the human eye. 

In terms of smell, moldy weed will smell like hay or have a musty smell — kind of like your bath towel when it needs washing.  

Signs That Your Weed Has Gone Bad

If you’re unsure how long your weed has been waiting for you to remember it, you should abide by some rules.

Here are the following tips to make sure you won’t be smoking stale and moldy weed:


Marijuana that has met its expiration date will crumble into a kief-like powder when you attempt to break it up — and this isn’t a good thing.

Sign That Your Weed Has Gone Bad

When checking your bud over for the mold growth, make sure you’re looking at trichomes and not mold upon closer inspection. This is because the mold likes to grow on top of the trichomes, so it can be tricky to distinguish it if you don’t know what you’re looking for.

Fresh, dank weed will look something like this.

It will have a vibrant green color, with flecks of orange or purple. In addition, it will also be slightly dried and sticky. If your marijuana isn’t sticky and looks brown-colored, this means that it has gone bad and could contain mold. 

Another good way to check for mold is by breaking apart the nug, and if you see mold running through it, trash it! 


Terpenes are the compounds responsible for giving weed its smell and flavor, and unfortunately, they don’t last long if you don’t store your weed properly. 

But, it does make it easy to determine if your weed has gone bad. Usually, if the cannabis buds are good and fresh, you would be able to smell your weed through your bag filled with buds. So, if your stash still smells like marijuana — it should be safe to consume. 

If it smells like mildew, there is a good chance it’s moldy. In that case, it is better to avoid this weed since it has dried out. 


If your long lost stash passes the appearance and smell test, load it up and take a small hit. If it tastes off or is stale, you’ll notice it immediately, giving you your answer about if it went bad. 

Avoid smoking this weed to save yourself from a bad smoking experience and go to a trusted dispensary to buy yourself a fresh and potent weed.  

Trust us, it is not worth your time and money to smoke bad weed. 

How to Prevent Mold on Weed?

The most important thing to take away from this article is how to determine if your weed is moldy, and how to properly store it. 

Oxygen, temperature, humidity, and light all play a factor in how long it will keep for, so we recommend ditching tins, plastic baggies, and plastic containers — and suggest switching to glass jars that have an airtight seal instead.

You can find glass containers at most dispensaries or online. Also, be sure to store it in a cool, dark, and dry environment, but NOT in the refrigerator or freezer. These environments are too cold and will dry out your product, and cause mold to develop faster. 

If you store your weed properly and keep it sealed away from sunlight, moisture, and heat in an airtight glass container, it will keep for about a year. If you follow the tips and tricks we outlined for you, you’ll have no problem determining if your weed has gone bad or not.

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