Can Weed Expire? Guide to Cannabis Product Lifespan

Long-term medical marijuana patients will know that cannabis distillates and oils can last for many months, but may not be sure about cannabis flower or other products; so, can weed expire? Many cannabis products indeed have a long shelf life, but fresh cannabis flower is a natural product and can therefore expire or even go moldy after some time.

Knowing how to look after your weed is the best way to ensure your product's longest possible shelf life and avoid any unwelcome mold growth. Understanding how to identify old weed will also help you ensure that you only inhale or ingest weed that’s safe to consume.

Does Weed Expire?

Yes, weed expires—whether we’re talking about dried buds or cannabis-infused products. Though optimal storage conditions are key to lengthening your weed's shelf life, it won't last forever. Just like many other products, exposure to light, air, and moisture will lead to the deterioration of the product. Similarly, the passing of time will also affect your weed's quality. 

Weed doesn't "expire" in the same way that milk or bread does. Instead, when weed passes its shelf life, its aroma, flavor, and potency will fade, leaving you with an inferior and perhaps ineffective product.

Research has shown that THC loss is proportional to its storage time, with the average concentration of THC in plant material decreasing by 16.6% after one year. In this study, THC loss increased to 26.8%, 34.5%, and 41.4% after two, three, and four years respectively. Though weed may be safe to use after some time, MMJ patients should be aware that its effects may be reduced due to gradual THC loss.

The Shelf Life of Different Cannabis Products

As a rule of thumb, most types of marijuana can stay fresh for a year or more if stored properly. However, some cannabis-infused products may have much longer lives. Much of what we know about products' shelf lives is anecdotal and also depends on their storage conditions and/or the ingredients used.

Flower

Properly stored flower can last up to 18 months, but you may find that the potency starts to fade after six. Flower's shelf life can be extended by proper drying, curing, and storage.

Edibles

Different edibles will have different shelf lives depending on their ingredients. Products like brownies with perishable ingredients like eggs may only last for two to three days. Cannabis-infused candies tend to last six to nine months. The edibles you purchase in your dispensary may contain preservatives to extend their shelf life.

Cannabis-Infused Cosmetics and Topicals

Cannabis topicals like gels, creams, or oils tend to last for up to two years. Soaps may endure for longer due to their alkaline nature.

Vape Oil

Vapes are one of the most long-lasting cannabis products because vape pens protect the cannabis extract from damaging environmental factors. Vape pens may last for up to two or three years.

Tinctures

Alcohol-infused CBD tinctures may be okay for up to ten years while oil-based tinctures can last for up to two years.

Signs that Your Weed Has Expired

If you suspect that your weed is past its best, check for the following signs that it might have expired before consuming it:

• Check for any obvious signs of dryness. Weed that's faded from its true lush green color to a dull green or even brown might have expired.

• Smell your weed to detect any loss of aroma. Cannabis with little to no smell has probably lost its flavor too.

• Touch your weed to see how dry it is. While fresh cannabis is soft, expired marijuana will become dry and brittle.

Effects of Consuming Expired Weed

Expired weed shouldn’t present any major dangers for recreational consumers or medical marijuana patients. However, there are two main reasons why MMJ consumers are best off avoiding expired weed:

1. MMJ patients in Arizona consume weed to treat AZ qualifying conditions. Sub-par products may not provide the relief they need. 

2. Weed can become less predictable as it ages, meaning its potency or psychoactive effects could change.

While expired weed may simply offer inferior effects, smoking moldy weed could be dangerous. Check your product carefully before consuming it.

Moldy Weed (and How to Recognize It)

It's particularly important for MMJ patients to know how to spot mold on weed. This is especially true if you're consuming weed to treat conditions that affect your immune system like cancer or HIV/AIDS.

There are two types of mold typically found on poorly stored marijuana: powdery mildew and gray mold. 

Powdery Mildew

It should be fairly easy to see if your weed has mildew. Look for fuzzy, white powder that's often apparent even from a distance. 

Gray Mold

Gray mold may be slightly more difficult to identify as it often exists within the flower. This makes it scarcely visible to the naked eye. If your flower is dry or has a dull appearance, check inside the cola (the central cluster of the flower) for more signs of mold. If you see gray discoloration or growths on the plant that look like cotton, you may have gray mold. 

Other Types of Mold

Wilting leaves, discolored roots, and dark spots on your plant are also signs of mold. It's best to dispose of any weed that you suspect has mold.

How to Store Weed for the Longest Possible Shelf-Life

Storing cannabis correctly is the key to keeping your weed fresh for as long as possible. The optimal storage conditions will include the following four main considerations:

1. Optimal temperature: The cannabinoids and terpenes in your weed are best protected at temperatures of 70 ºF (21 ºC) or below.

2. Humidity: Overly humid conditions can cause mold to spread. Ideally, store cannabis buds between 55% and 65% relative humidity.

3. Oxygen: Keeping your weed away from exposure to oxygen reduces terpene and cannabinoid oxidation. Store your weed in an airtight container to slow the deterioration of cannabinoids and the evaporation of terpenes from the plant.

4. Light: Research suggests that light and heat can degrade and synthesize cannabinoids. This can convert THC into CBN (cannabinol) reducing the psychoactive effects of your weed.

Storing marijuana properly therefore requires storing it in an airtight container in a cool, dark place away from direct sunlight. A mason jar stored in a sock drawer is ideal.

Store Your Weed Properly for Potency and Safety

Storing weed properly goes further than simply reducing waste. For MMJ patients, ensuring optimal storage conditions is also a safety concern that reduces the risks associated with moldy or ineffective weed.

Choose a place to keep your weed that meets all the criteria listed above to keep your product fresh for as long as possible. It’s also a good idea to purchase only the amount of fresh weed you plan to consume and ask your physician to explain how to check the label to see when your medical marijuana expires. Not only will this make your weed consumption safer, but it'll also help it retain that delicious profile of smells and flavors that boosts the experience.