Long Term Storage Of Cannabis

Growing your own cannabis can often leave you with more than you know what to do with. Although this is technically a good thing, you'll need to figure out how to store your buds for the long term if you want them to stay fresh, full of flavour and maintain their potency. Keep reading to learn about proper storage so you can stash your weed knowing it won't go moldy or turn bone dry.

Drying & Curing Cannabis

Cannabis buds begin to degrade as soon as they are harvested from the plant. In order for a grower to preserve the cannabinoids and terpenes on the flower, certain conditions need to be met. If the buds dry fast they lose flavour and potency and if they dry too slowly there is a risk of mold developing.

Drying and curing your cannabis buds at the right pace gives time for sugars to break down that would otherwise remain in the buds. The optimum RH for drying is between 45-55% with a temperature set no higher than 21-22°C. Please see our article on drying and curing cannabis for further information.

As cannabis gets old, THC begins to degrade and turns into the less desired CBN. Although you can still get an effect from aged weed, it might not be as potent and flavourful as when you first tried it out. The terpenes eventually dry out and lose vitality.

The purpose of drying and curing is to bring out the full flavour and potency of the plant, which needs to be accurately controlled to prevent mold. The process can take some months, but once the buds are properly cured they are ready to be stored for the long term.

How Long Does Cannabis Last?

The main things are to not let oxygen, light or moisture reach your buds or they will begin to degrade faster. Prolonged light exposure and higher temperatures speed the process up. When the conditions are right, cannabis can be stored for up to 4 years without losing potency, according to the following information.

A 4 year long study was completed in Italy in 2019 that indicates cannabis stays fresh for longest at low temperatures under minimal exposure to light. The study showed the change in the chemical compositions of THC, CBD and CBN in 6 different samples seized by law enforcements. These 6 samples were split into 4 groups to create 24 samples that were tested 14 times over the 4 year period.

The groups were set as follows:

• 6 samples exposed to light at 22°C for 24 hours per day
• 6 samples in darkness at 22°C for 24 hours per day
• 6 samples in darkness and refrigerated at 4°C for 24 hours per day
• 6 samples in darkness and frozen at -20°C for 24 hours per day

As expected, the results showed that the samples at room temperature degraded fastest, and displayed significant conversions of THC to CBN. Just in the first 6 months of the study the two first groups 'lost' between 11 and 13 percent of their THC, the latter being the samples that were exposed to light. However, there was still a decline in THC in the frozen cannabis, but it did preserve for the longest.

From this we can safely conclude that freezing is the best solution for keeping buds fresh long term.

Long Term Storage Of Cannabis

There are different methods growers use to store their cannabis long term, but it is rare people store it for more than a year or two anyway. You can either keep it properly sealed in glass jars (in a dark place) or vacuum pack it and freeze it. We'll go over both of these methods, as they both work well when managed correctly. As we've seen, freezing makes the weed last longer but jars can work very well if they are maintained correctly.

Storing In Containers

With the proper packaging, containers and storage, weed can be kept for a long time without being frozen. There are all sorts of containers for storing our weed in, from simple wooden boxes to pro glass jars with UV protection and humidity control.

• Airtight glass jars
• Dark glass with UV protection
• Wooden boxes such as humidors
• Plastic vacuum bags
• Sealable stainless steel pots with lids

It is a good idea to add a humidity pack that maintains the humidity in the container at roughly 60-65%. We also recommend vacuum sealing the weed to remove most of the air but without compressing it completely, and then keep it in containers.

Q1 2016 | NL a.reg | PC case | My 1st gr

Storage containers can then be stored in a cool, dark place away from any light. If you plan to fill your personal stash jar up once in a while, consider dividing your harvest into different packs so you can take more weed when you need it without having to open and reseal your packages.

Freezing Cannabis Flowers

Preserving fresh or dried cannabis flowers for the long term requires you to freeze them. To avoid damaging the buds under a vacuum, you can put the buds in a zip-lock bag, squeeze most of the air out and close it tightly. Vacuum-seal the zip-lock bags and put them in an airtight container in the freezer set below 0°C . This will allow them to be stored for years to come.

Defrosting your cannabis should be done with care to avoid damaging the trichomes, which become extremely brittle when they are cold. When thawing your vacuum sealed packs of weed, make sure to avoid handling them until they have completely defrosted. On that note, during storage you may want to keep the vac packs in containers to prevent you from damaging the weed when rummaging through the freezer for something else.

Tip: If the buds are not dried enough and there is oxygen in the container you may see ice crystals forming.

Vacuum Sealing

Vacuum sealing is useful for removing oxygen and moisture from surrounding the bud. Both air and excess moisture can speed up the degradation process so if you want to keep your weed for a long time, it's best to remove as much air as possible, even if it means squashing your weed slightly. The buds can fluff out again once released from the vacuum, but trichomes may have been damaged.

Storing Concentrates and Extracts

Freezing cannabis is also done for making certain concentrates or extracts, like bubble hash, live rosin or BHO. The flowers are frozen either fresh or dried to be later processed.

Temperature has a big effect on the consistency of concentrates and extracts so in order to maintain them in a certain form, temperatures need to be low. Shatter, for example, begins to cloud up and lose quality when exposed to room temperature. We recommend storing your cannabis concentrates in a sealed, airtight container in the fridge or freezer.

Weighing up by Basementganja from GrowDiaries.

Cannabis Edibles

There is plenty of food which can be stored in the freezer for the long term without going off, especially if the food contains sugar. Cannabis edibles can be packaged in paper or aluminium foil, vacuum sealed and kept in a Tupperware. Simply defrost when you are ready to eat some green.

If you found this article useful or have any tips on storing cannabis for the long term, please feel free to share your thoughts in the comments section below!

External References

The role of time and storage conditions on the composition of hashish and marijuana samples: A four-year study. - Zamengo L, Bettin C, Badocco D, Di Marco V, Miolo G, Frison G. (2019)

Metabolic Profiling of Cannabis Secondary Metabolites for Evaluation of Optimal Postharvest Storage Conditions. - Milay L, Berman P, Shapira A, Guberman O, Meiri D. (2020)

The stability of cannabis and its preparations on storage. - Fairbairn JW, Liebmann JA, Rowan MG. (1976)

This article was updated January 2021.