can marijuana be frozen

Can You Really Freeze Cannabis?

Freezing cannabis might sound like a strange idea, but it’s becoming an increasingly common practice amongst ordinary decent home growers and large commercial growers. Sure, there are some risks. There are also dank rewards. Here’s what you need to know about chilled stash.


It’s probably not that surprising to hear that lots of growers freeze their cannabis post-harvest. Perhaps you’ve dabbled yourself. It’s a pretty common practice to store dry sugar leaves in a Pyrex lunchbox in the freezer for hash-making at a later date. But some will go a step further and freeze the flowers. Outdoor growers that cultivate cannabis seasonally or even biannually are the grand masters of stash preservation.

If your aim is to remain self-sufficient rather than cashing in on a bumper harvest, the typical go-to glass jars might not keep your stash fresh for long enough. Most growers will agree that a good old-fashioned Kilner jar stored in a cool, dark place will keep your buds dank for about 18 months. However, if you’ve harvested a few 1kg monster plants and don’t want any weed going to waste, you need a method that can extend the shelf life even longer. You don’t have to invest in cryogenic preservation, but freezing that weed could be the best option.


The cannabis harvest standard operating procedure to trim and slowly dry flowers first must be followed. A vacuum jar is probably the best choice, or really any storage box without a static charge like plastic can work. Pack with buds and make sure it’s tightly sealed. Now you can safely place your stash in the freezer for long-term storage.

A year or two later when you need the stash, simply take it out of the freezer and let it thaw. Keep your hands off it while it’s still frozen, as the trichomes will be very fragile. Also, don’t be tempted to do anything silly like defrosting your frozen flowers in the microwave.

Typically, the top layer of frozen weed will be less than perfect as air and water may have degraded it to some degree. Overall, a frozen stash is still a quality product and comparable to buds stored in the usual manner. If you can avoid breaking the seal and dipping into the buds, you have every chance of succeeding.


We can’t take the credit for this cool **hash-making method. In fact, it was the National Geographic TV series “American Weed” that turned us on to making hash in a flash. Simply toss your sweet leaf trimmings into a bucket and add a few lumps of dry ice. And for the love of god, remember to wear gloves or you will need to rush to the nearest A&E to try and save your fingers from falling off.

Once the trim and dry ice are safely in the bucket, all you need to do is agitate it with a bit of a shake and a swirl. The dry ice draws out the trichomes through the process of sublimation. Finish by sieving the contents, and you’ll be left with beautiful blonde hash powder. From start to finish, the whole process takes minutes rather than hours.


Bubble hash has always been a favourite solvent-free hash of ours. Nothing compares to full-melt ice hash. For best results and a variety of grades of hash, a multi-bag kit is essential. Although, you will probably need a handheld whisk to agitate a bucket full of material and manually wash the trichomes off. As they fall off, the various micron screen bags will catch the hash.

Alternatively, if you want to expedite the process and not have to clean a real mess afterwards, a Bubbleator B-Quick can make the hash for you automatically. All you need to do is add ice water and sticky green. Deliciously efficient.


Freezing fresh flowers is best left to the professionals with the expertise and equipment to do the job right. In the US, extract artists really are cryogenically freezing freshly harvested buds. Then, various BHO extraction methods are used to create a live resin concentrate.

Live rosin is another sub-zero cool concentrate. Now, this really dials the dankness up to 11. Freshly frozen flowers are converted into bubble hash. This is then scooped up and placed in an industrial freeze dryer for 24 hours. Finally, a pro rosin press is loaded with the dry bubble hash and squished into live rosin.


There are plenty of misinformed naysayers that would have you believe freezing cannabis is a bad idea. We strongly disagree, because our research and personal experience suggests otherwise. Freezing cannabis to keep it fresh for longer is a real option for home-growers. Similarly, bubble hash is not too difficult to make. But if you want to enjoy the flavoursome, more exotic dank delights like live resin and live rosin, be prepared to pay a premium price at your local dispensary or coffeeshop.

There is much confusion about freezing cannabis. In this blog, we explore the benefits and the potential pitfalls associated with the process.


As anyone who has ever found and smoked some forgotten cannabis flower will happily tell you, old, badly stored cannabis is no fun to consume. You probably know that you shouldn’t leave your marijuana out, but what’s the best way to store your cannabis? Do you know what the optimal temperature for your cannabis is? Have you ever thought about the humidity of where you store your cannabis?

One Italian study makes the case that you should freeze your cannabis. Yes, researchers found that putting cannabis flower in the freezer maintains the level of tetrahydrocannabinol (THC) better than other storage methods do.

Let’s explore why this is and go over the best way you can freeze your cannabis at home.

Cannabis Storage 101

There are three basic variables involved in storing cannabis:

  • Light
  • Temperature
  • Humidity

Light is the easy part. You may already know that light is bad for your cannabis, but did you know cannabis farmers cure and dry their plants in low light, because of the various negative impacts? These negative impacts include:

  • Increasing the speed of drying
  • Over drying
  • Lowering the potency of THC

So, an easy solution for you to keep light away from your marijuana is to store your cannabis in a container with a tight-fitting lid in a dark place.

Temperature is a much more interesting and hotly debated topic. The recent study from Italy— using actual science—found that THC degrades slower at lower temperatures. Though the researchers didn’t test temperatures above “room temperature,” evidence elsewhere already suggests hot temperatures are indeed worse still for your marijuana.

As for controlling for humidity, many storage tins or other containers have humidity-controlling items within and are usually kept at room temperature. This controls for two of the three important variables: light and humidity.

Humidity is vital. Too humid, and your cannabis may start to rot or get moldy. However, storage like this doesn’t control for temperature, and this is the second-most important factor, other than avoiding rot and mold.

Italian Study Finds Frozen Cannabis Maintains THC Levels Best

The study out of Italy, which was published in Forensic Science International, looked at cannabis samples stored:

  • At room temperature
  • In a refrigerator (4 degrees C)
  • In a freezer (-20 degrees C)

During the four years the study took place, researchers tested the samples 14 times. They found that:

  • THC levels in the cannabis stored at room temperature dropped over time.
  • At room temperature and in light, THC levels decreased by 13% after 100 days.
  • At room temperature in the dark, THC levels decreased by 11% after 100 days.
  • The refrigerated marijuana samples also lost THC content, but not as much as the room temperature samples did.
  • In the frozen cannabis, THC levels mostly stayed the same.
  • In all samples when THC went down, cannabinol (CBN) levels went up.
  • Cannabidiol (CBD) content stayed stable across all cannabis samples during the experiment.

Should You Put Your Cannabis in the Fridge?

So, this evidence shows freezing cannabis is the best way to keep THC content stable. This leads to some potential impact on how you store cannabis.

If you’re not quite ready to freeze your cannabis, you may be thinking that the fridge is your best bet for storing your marijuana. Personally, I have some concerns about being able to control humidity in a refrigerator.

If your fridge’s humidity control has any issues, the risk of total cannabis loss is significant. Think about your vegetables in the crisper drawer. Keeping them in there may delay decay issues, but it’s not going to keep them fresh for more than a week or two.

So, then should you really freeze your cannabis? There are a lot of people who have issues with this idea. The main complaints are around the fragility of the trichomes.

Trichomes are the little crystal-like formations you may be able to see on your cannabis buds and on some leaves. They’re where the majority of cannabinoids, terpenes and flavonoids reside, so you definitely don’t want to damage them. People say that once the trichomes are frozen that they’re easy to break off, and that using freezer bags creates static, which can also damage the buds.

Well, you can resolve both of these issues by freezing your cannabis in glass mason jars. If you grow your own cannabis, you can use the same jars you used to cure your harvest. Post-curing, simply put your storage jars into the freezer.

Your flower will be freshly dried and cured, so water content will be low, allowing for easy defrosting later. Plus, by keeping your cannabis in the same container, you won’t be exposing it to any outside environmental factors that could degrade the cannabinoids.

Why I Freeze the Fresh Cannabis That I Use to Prepare Edibles

I’m lucky enough to be able to grow my own cannabis at home. While I haven’t used the freezer for my already dried and cured cannabis yet, having seen the data in this study, I will likely experiment with half my stock next year.

I do, however, freeze some cannabis buds and leaves for making edibles. While many simply trim their cannabis buds and discard the rest, why not use the whole plant?

Freezing the sugar leaf is a no brainer for me. I simply remove the fan leaves (leaves without trichomes) and freeze the whole sugar leaf (leaves with trichomes) and buds whole after harvesting—no drying, no curing.

Then I defrost the cannabis as part of my decarboxylation process. I have to cook the cannabis for use in edibles, so defrosting is a simple extra step.

I trim the best buds for smoking, and the smaller or harder-to-trim pieces go straight to the freezer. This seems to help preserve the terpenes as well.

I’ve made the mistake of using freezer bags, and I won’t do that again. First off, they aren’t 100% scent proof. Second, I’ve seen that they allow damage to the trichomes. So in the future, I’ll use glass containers.

Another reason home growers may want to instantly freeze cannabis without drying and curing is to make concentrates—for example, fresh frozen hashish. This makes very pure hashish with flavor profiles very close to the fresh plant.

Some of my classmates at Oaksterdam University also looked into using frozen samples for other methods of concentrates. It’s easy to see the appeal of frozen cannabis:

  • Less work
  • Less time
  • Better flavor
  • More terpenes

If you don’t grow your own marijuana, freezing may be an unnecessary step, because you use what you buy before it matters. But for home growers or for folks who have a large stock of cannabis and who are worried about maintaining the quality of the flower before they get around to consuming it, freezing appears to be a good way to go.

I’ll be trying out freezing on my dried and cured bud, and I’d recommend freezing for anyone who’s interested in making their own edibles and some concentrates.

For anyone who has grown their own cannabis and has become bored with trimming (I’ve found it to be a very tedious part of the otherwise fun and interesting growing process), freezing bud for edibles and concentrates is not only easier and better, it also means a lot less trimming.

Photo credit: Canna Obscura/

If you’re new to cannabis and want to learn more, take a look at our Cannabis 101 index of articles. And if you have questions about cannabis, ask them and our community will answer.

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You probably know that you shouldn’t leave your marijuana out, but one study makes the case for freezing cannabis—to help keep cannabinoid levels up. ]]>