Does Marijuana Go Bad?

By Last updated on November 9, 2020No Comments

First and foremost, marijuana will not go “bad” in the sense that it will cause harm to a user. Weed is different from food in this respect. When we say that food “goes bad” or “rots,” we mean it is unsuitable for human consumption. Food goes bad because microorganisms colonize it and the gases released by its decomposition are the cause of the awful smell you get.

Unlike food, cured and dried cannabis is not a breeding ground for microorganisms. You still have to worry about them if you are growing a cannabis plant because it is living.

If you have very old weed that has been stored properly, it is probably okay to use it. It can, however, have a noticeable drop in potency, which can be a big deal if you are using it for medical purposes. Older weed can also change in taste and texture.

does marijuana go bad

What happens to weed if it is old?

There are over 110 identified cannabinoids in marijuana, with THC and CBD the most abundant, followed by CBN. The cannabinoid composition varies depending on the strain. When your marijuana has been harvested, cut, and dried, its cannabinoid content begins to change over time because cannabinoids react to the presence of oxygen, light, and heat.

As weed grows, it produces cannabigerolic acid (CBGA) which is synthesized into CBCA, CBDA, and THCA. What is interesting is that the cannabinoids THC and CBD, for example, must be activated to take effect. Raw cannabis contains THCA which does not become THC until you apply heat to decarboxylate it.

Once you expose THC or THCA to UV light or the atmosphere for a long enough period, further changes will happen. Eventually, the compounds degrade to CBNA and CBN. To be clear, CBN (cannabinol) is not bad for you at all. However, it will not provide you with the psychoactive high you seek.

CBN is an effective sedative, so if you want to get some sleep and feel the relaxation in your muscles without a potent psychoactive high, you may enjoy the experience. If your weed is extremely old and was not properly stored, the buds will have dried out, and you will probably endure a very harsh smoke. You can alleviate some of the problems by vaping the old weed, but it combusts quicker than new flower, so do not expect to get much vapor.

Pulling apart the nugs should tell you everything you need to know about the condition of the weed. You can determine whether there is any moisture content or see if it falls apart in your hands. Herb that is well cured and dried will make a snapping sound when you handle it, whereas old cannabis makes a cracking sound and also feels extremely dry.

Old edibles

Cannabis labels on products such as edibles can tell you when the product should be used by. Everything from cannabis edibles to tinctures to concentrates goes through the same degradation process as cannabis flower. Similarly, cannabinoid content in these products is affected by exposure to light, heat, and moisture. Edibles with ingredients such as milk and eggs can spoil quickly, rendering your edibles useless.

Old concentrates

Cannabis concentrates experience the same changes if left exposed to light and air over time. The cannabinoids and terpenes in the substance will degrade, so old concentrates will not taste as good as new ones, and will also have a high CBN content. If you want to slow down the process of degradation, it is necessary to remove UV light and oxygen, the two factors that cause the chemical change.

Old vape pens

As with any other cannabis product, it is best to keep your vape pens away from direct light. Because the cannabis oil is already inside an airtight cartridge you do not need to worry about humidity or exposure to air.

Also important, store your vape pen standing upright, as this will keep all the oil at the bottom of the cartridge, ready for immediate use.

How long does weed stay fresh?

When stored properly, dried cannabis keeps for 6 months to 1 year. Over time, it begins to lose its aroma and potency. According to 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

Can old weed become dangerous?

Besides tasting stale and smoking harshly, dried out old weed is usually not harmful to humans. However, if stored in too humid or moist of conditions, your flower nugs may suffer from a mold infestation, which can be harmful to your health.

Moldy buds can exhibit a fuzz or dark spots within its leaves. Mold gives off a musty odor reminiscent of urine or sweat. If your weed smells unpleasant, play it safe and throw it away.

Even if your weed is not super old, it is best to do a mold inspection. A study by researchers from the University of California, Davis found bacteria and mold on 20 cannabis samples bought from dispensaries and pot growers in Northern California.

In people with weakened immune systems, inhaling smoke or vapors from weed containing bacteria or fungi could cause serious illness.

How to keep weed fresh for longer?

Different cannabis products have slightly different needs if you want to keep them fresh and potent. Here is a breakdown of how to keep different cannabis products fresher for longer:


To keep flower fresh, you need to store it properly. This includes limiting exposure to light and open-air and maintaining a proper humidity level, typically somewhere in the range of 54 percent to 63 percent.

To accomplish all this, store your bud in either a small glass Mason jar or a container designed specifically for weed. Keep the lid on tight, do not open it very often, and keep it in a cool dark place.

If you want to go above and beyond in your storage practices, invest in humidity packs that remove excess moisture, and release it when needed. Some humidity packs are specifically designed to maintain an optimal relative humidity of around 62 percent.

For larger and extended storing options, consider vacuum sealing to remove all air from a package. If you decide to take the vacuum sealing route, make sure to avoid using a material that uses bisphenol A (BPA).

Some people think that putting weed in your freezer is a good solution, however, this is incorrect. Freezing temperatures can cause trichomes (the tiny hairs on flower 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 when thawed out for use.


To keep edibles fresh, leave them in their original package and store them in a place that is away from open-air and direct light. Be sure they are in a cool location, as many types of edibles, especially things like hard candies and gummies, can easily melt. Many users keep their edibles refrigerated or frozen to extend their shelf life.


The best way to keep your concentrates fresh and potent is to store them in small containers designed specifically for dabs. These are typically made out of glass, silicone, or a similar material. Keep the lids on tight and store the containers in a cool, dark place.

The Sanctuary Editorial Team

The Sanctuary Editorial Team

Our writers use a combination of research and personal experiences to eloquently tackle these topics. We also examine scientific publishings for up-to-date research. The accuracy of our articles is crucially important to us and they are written with the idea of inclusiveness for readers of all walks of life.