Does Weed Go Bad?

Liz Filmer
23 Mar 2023

Weed does not go ‘bad’ in the sense that it will cause you harm. Unlike food, it is not a breeding ground for microorganisms. Therefore, it is probably ‘okay’ to use if you have old weed appropriately stored. However, it won’t be as potent as before.

One thing sure to happen, though, is a reduction in potency. There are over 110 recognised cannabinoids in cannabis. However, when your weed has been harvested, cured, and dried, its cannabinoid content will alter over time. This is because cannabinoids react to the existence of oxygen, light, and heat.

Once you reveal THC  to UV light or the atmosphere for a long enough period, additional changes will happen. The cannabinoids begin to degrade into CBNA and CBN. CBN isn’t ‘bad’ for you, but it won’t deliver you a psychoactive high.

CBN is an effective sedative, so if you want to sleep and rest without a high THC, you may appreciate the experience. However, if your weed wasn’t appropriately stored, the buds will have dried out, and you’ll likely experience a harsh smoke. 

Weed can develop mould if it has been stored with an extreme level of moisture in it. Using mouldy cannabis is a danger to your health. Mould resembles a thick cobweb and typically has a grey colouring. Smoking mould signifies inhaling thousands of toxic spores, which can provoke severe respiratory problems. Regardless of its age, you should dispose of any mouldy weed you find.

Ancient and dried-out weed will easily break apart into a fine powder resembling kief. You can identify mould reasonably quickly. Mould grows over trichomes and looks like white powder covering every surface of the plant matter. You will also spot mould when you break apart the nugs.

Terpenes degrade quickly on poorly stored weed. Therefore, if cannabis offers a pleasant aroma, it is almost undoubtedly fit for consumption. On the other hand, weed with a mildew-type smell is a sign of potential mould growth.

Pulling apart the nugs shows you everything you need to know about the state of the weed. For example, well cured and dried weed will make a ‘snapping’ sound when you pull it apart. In contrast, old cannabis produces a cracking sound and feels excessively dry.

If your cannabis passes all of the above, smoke a small portion to be sure. If it is ‘bad weed,’ you will taste it immediately. Heat, light, and moisture are the adversaries of long-term weed storage. If you want excellent-tasting weed months after purchasing or growing it, keep it in an airtight container in a cool, dark place.

Liz Filmer