Does Weed Go Bad? Here’s How You Can Tell

If you’re looking for a short and simple answer to this crucial topic, it’s “Yes.” Cannabis is an organic, living plant that can expire at every stage, from the very start of growing to the dried and carefully curated final product in its dispensary packaging. It would be a shame to spend your hard-earned money on important medicine just to toss it out because your living, organic material rotted out from improper storage.

This article will break down the process that goes into making sure that dispensary cannabis retains its top-quality, the best ways to store cannabis once you buy it, and warning signs that it’s time to toss wilted old buds into the trash. Let’s get right into it!

Table of Contents
  1. The Importance of Curing
  2. Tips for Cannabis Storage
  3. How Long Does Cannabis Keep Fresh For, and How Long is it Usable For?
  4. Does Weed Get Old?
  5. How Long Do Concentrates Keep For? Does Hash Go Moldy?
  6. Can I Smoke or Salvage Moldy Weed?
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The Importance of Curing

Curing means leaving the dried cannabis buds you’ve obtained from your local dispensary or home grow operation in an airtight jar and “burping” the jar every so often. Burping cannabis flower will properly break down the sugars and chlorophyll within the plant and improve the flavor of the product as the terpenes become more pronounced over time. Letting out the air periodically also prevents trapping moisture in the jar and growing mold on the plant. Cannabis flowers must be properly dried and cured, not only to produce a more pleasant experience, but also to prevent the cannabis from going moldy.

While this might seem like an unimportant and pointless step, it’s one that will buy you extra time once you store that cannabis properly!

Tips for Cannabis Storage

Cannabis buds are more prone than other marijuana products to going bad over time, especially if the flower is not properly stored. Concentrates on the whole may last a little longer, but like certain types of hashish, they may have some plant matter residue in the final product that will go bad over time.

Putting your buds and concentrates in airtight containers, for instance a mason jar with a lid, will help keep them fresher longer. Keep in mind, cannabis slowly loses potency the longer it goes unused.

What Moldy Weed/Marijuana/Cannabis Looks Like
What does mold on weed look like? Source

Avoid Hot and Humid Environments

Exposure to too much sunlight and air will seriously reduce how long cannabis will resist going bad. Humid environments are generally bad for all plant types. So no surprise that cannabis prone to mold and mildew in such environments. Many cannabis adepts who live in hot and humid places also vacuum-seal and try freezing their cannabis buds in order to cure their bud properly.

Use Airtight Containers

The best way to store cannabis is in dry, airtight containers, such as a mason jar with a clean lid. Some growers use humidity packs to keep cannabis buds dry and ripe for even longer regardless of the environment the grower lives in. Whether you are an expert grower or novice, mason jars are a good buy for anyone wanting to keep their cannabis in the best condition possible. The jars are easy to find, dirt cheap, and are world leaders in quick, easy, effective cannabis storage.

Leafwell does not advise keeping cannabis in plastic bags for the long-term.  Baggies are problematic for two reasons:

The little fuzzy plant hairs on dried cannabis flower, called trichomes, often fall off due to static. Trichomes are important for the flavor, potency, and smell of cannabis buds. You want to preserve them as much as possible.

Plastic baggies also make the bud “sweat” and smell (and not in the way you want). Sweat leads to excess moisture in the storage container, and, it bears repeating, that can make your cannabis moldy.

How Long Does Cannabis Keep Fresh, and How Long Is It Usable?

Assuming it’s being kept properly, most cannabis plants will cure and peak for about three to six months. After that, it starts to lose potency. Its THC (formally known as tetrahydrocannabinol) will slowly degrade into the cannabinoid, cannabinol (CBN). CBN may help induce sleep and relaxation, but tends to produce little psychoactive effect..

In fact, some marijuana connoisseurs deliberately store their cannabis for extended periods in order to adjust the ratio of THC to CBD to produce varied effects.

If you’re sitting on some lovely cannabis waiting on a special occasion, keep that THC degradation in mind!

Does Weed Get Old?

Once harvested from the original cannabis plant, properly kept dried cannabis buds may keep for about a year, but will generally start to lose potency near the six to eight month mark.

Assuming it hasn’t gone moldy after a year in storage and has been kept in an airtight container, cannabis will be usable for 18 months to two years. Its effects will be less strong at the end than at the start.

Uses for Old Weed

No need to be too upset if you have a jar of cannabis that’s past it’s estimated expiration date. You’ll still be able to get some use out of it!

Many DIY marijuana enthusiasts use older cannabis to make oils and butters, which help keep their produce fresh for a little longer and increase its potency.

As mentioned, the THC in older cannabis degrades to CBN—which can be used to help bring on sleep. If you have old weed that hasn’t molded, try making your own cannabutter with it for a healthy sleep aid that can be especially useful for anyone struggling with insomnia.

How Long Do Concentrates Keep? Does Hash Go Moldy?

Hash, tinctures, and concentrates should all be kept in airtight containers out of direct sunlight. Most well-crafted  hashes, tinctures, and concentrates when stored properly will stay fresh and usable for around five years. If you’re looking for a cannabis product that has the longest shelf-life, concentrates are tough to beat!

However, different types of hashes keep potent for different amounts of time, depending on how much plant matter it contains, how tightly pressed it is, and how long it gets “knocked around” (remember, those trichomes are important!)

Talk with your local dispensary’s bud tender or consult the hash brand you’re buying from to learn as much as you can about the hash you intend to purchase. Knowledge is wealth when it comes to implementing proper storage procedures.

How the Hash Production Method Affects Lifespan

Why exactly do hash lifespans vary so much? The differences  have to do with how the hash is made.

Some production methods for making a hash or other concentrate produce a purer product than others. Concentrates, waxes, and hash oils made using supercritical carbon dioxide (not solvents – they can leave nasty impurities in the final product) will  last longer than hash made from traditional methods like ice extraction, pressing, and bubble bags.

Hash made using the traditional methods generally keeps a little longer than buds – about 2 to 2.5 years if stored responsibly – but starts to lose potency after around six months.

Because more of the organic material that can mold or rot is removed from the final product, purer methods of hash-making, which strip the cannabinoids away from plant material, will keep for around three to five years. Potency will still diminish after six months or so.

Moldy hash and buds can be used to make purified oils. These processes can remove mold during manufacturing. Since hash, oils, and other concentrates do not need to be cured like buds do, they are most potent within the first month of creation.

Hash and concentrates made from properly cured marijuana buds tend to produce better results (because less water from the buds dilutes the mix). Many home hash makers report a better experience by leaving hash to cure for about a month or two, especially if using bubble method. Curing will help keep your hash potent and pathogen-free for quite some time.

Cannabis with White Mold
White mold on cannabis. Source

Can I Smoke or Salvage Moldy Weed?

If you find mold anywhere on your cannabis, throw it away. The health risks aren’t worth keeping it. If you recently bought something from the dispensary and find mold on it, take the product back and complain. Dispensaries are responsible for selling a quality product. You should be refunded for any products that are defective or were improperly stored. Ensuring you get the best out of your medicine will save you not only money, but also your health.

Some diehards suggest making moldy cannabis into butane hash oil (BHO). This is not recommended. Mold can still contaminate the final product. Breathing in mold is dangerous. You do not want even a small amount in your lungs, especially if you have an allergy or are immunocompromised in any way.

Conversely, if you find a small amount of powdery mildew on your marijuana plants, you can safely get rid of it. One of Leafwell’s favorite growers, Jorge Cervantes, shows us how to do so here:


Like any medicine, medical cannabis needs to be properly stored and consumed in a reasonable timeframe to maintain potency. In every stage of its life, the marijuana plant needs to be carefully cleaned, cured, and taken care of. If you grow your own cannabis, you’ll want to ensure you cure your product properly, as it will last longer.

Store your cannabis in an airtight container away from sunlight and humidity. If you don’t have mason jars, invest in a few to help preserve your medical marijuana. Remember to clean them regularly. Make sure they’re completely dry before using them for storage. If you find mold on your buds, throw it away immediately to avoid breathing in dangerous toxins.

Lastly, if you find your cannabis frequently molds before you use it, consider switching to hashes or concentrates, which have a longer shelf life than cannabis flower. All cannabis products, and especially buds and hash, should be regularly checked for mold and mildew. Dispensaries should be doing this all the time. Once you get your products home, so should you.

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Written by
Dipak Hemraj
Dipak Hemraj

Dipak Hemraj is a published author, grower, product maker, and Leafwell’s resident cannabis expert. From botany & horticulture to culture & economics, he wishes to help educate the public on why cannabis is medicine (or a “pharmacy in a plant”) and how it can be used to treat a plethora of health problems. Dipak wants to unlock the power of the plant, and see if there are specific cannabinoid-terpene-flavonoid profiles suitable for different conditions.

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