Store and keep cannabis properly

Everything you need to know about optimal cannabis storage
So that your weed always stays fresh

Mary in a Bottle in the grow! trade magazine, issue no.6 2020.

Image: Storing and storing cannabis correctly

Proper storage and preservation of cannabis is essential if you want to enjoy your buds for a long time.
Because the shelf life of all natural products is primarily dependent on external factors. These include light, air, humidity/mould and temperature.
If you want to store your weed so that it stays fresh and tasty for a long time, you need to keep these factors in mind when choosing your storage.

Thus, the German Hemp Association also recommends important factors to consider when storing cannabis:

Deutscher Hanfverband

Bei richtiger Lagerung sind Cannabisprodukte viele Jahre haltbar, ohne dass der THC-Gehalt wesentlich sinkt. Die größere Oberfläche führt bei Marihuana im Vergleich zu Haschisch zu einem schnelleren THC-Abbau und einer höheren Empfindlichkeit gegenüber äußeren Einflüssen. (…)

Luft und UV-Licht fördern den Zerfall von THC zu wenig bzw. nicht psychoaktiven Stoffen. Temperaturen bis zu 20° Celsius haben nur einen geringen Einfluss auf die Haltbarkeit. Höhere Temperaturen beschleunigen den Abbau des enthaltenen THCs. Bei zu hoher Feuchtigkeit kann Schimmel entstehen. Um einen Abbau von THC und Geruchsstoffen sowie die Bildung von Schimmelsporen zu vermeiden, sollte Cannabis also trocken, kühl und dunkel gelagert werden.

Dangers if cannabis is not kept and stored properly:

Grass becomes dry and straw-like

Loss of cannabinoids (THC, CBD etc.)

Mould infestation of the flowers

Loss of taste, smell and effect

To keep your grass fresh, we will now go into all the factors that have an impact on the quality of your grass.
If you apply this knowledge and take all factors into account, you will be able to store and keep your weed in the best possible way in the future. Then nothing stands in the way of tasty buds.


Protection from UV light is perhaps the most important factor when it comes to preserving your flowers for a long time. With prolonged exposure to UV light, the cannabinoids (e.g. THC or CBD) in your buds will continue to degrade. The effect of your weed decreases.

To counteract this, you should store your weed or the container in which your weed is stored in a place that is as dark as possible.
The only exception is violet glass.

Violet glass, is a special type of glass that has the highest light protection factor compared to all other types of glass, such as clear, brown or green glass. Violet glass is an energy storage glass, characterised with a special spectral range. This optimally protects the molecular structure of all substances and raw materials contained in the violet glass from sunlight damage. The contents of the glass are also energised and constantly revitalised. No other glass is able to preserve its contents as well as violet glass, and to enliven them to boot.

Bild: Cannabis richtig aufbewahren und lagern

Cannabis Medic Forum report on Mary in a Bottle and its benefits for cannabis patients.


Just like light, air also ensures that grass decomposes over time. For this reason, it is important to store your flowers in a container that can be sealed airtight. Additional benefit: When your grass is sealed airtight, it is also odour-proof - and thus protected from prying noses.

But even with airtight containers, there are various factors that may not be directly on your radar screen, but should nevertheless be taken into account.
Ordinary preserving jars usually have a rubber or plastic sealing ring to ensure an airtight seal. But plastic and rubber not only become brittle over time, they also give off vapours that have a negative effect on the taste of your flowers.

Vacuum bags, on the other hand, are already a better solution, as they completely remove the air from the container, which keeps the grass fresh and durable for a very long time. However, the pressure in the vacuum compresses the flowers very much. If the weed is already very dry, this will only make it crumble more easily.

Image: Glass cut 1

To ensure an airtight seal, the Mary in a Bottle has a special glass cut in the glass neck and glass stopper. With just a small screw movement, the closure is completely airtight. Because Mary in a Bottle is made of 100% glass, and glass is completely tasteless and odourless, your weed retains its natural aroma.


Striking the optimal balance of humidity between too dry and too humid is a little more challenging at first glance.
If the storage method allows too much moisture, you risk mould. However, if it is not humid enough, the terpenes and cannabinoids become weaker. You want to avoid both.

The optimal humidity for cannabis flowers is around 62%. But how do you achieve this humidity in your storage container and keep it constant?

The hygrometer packs from Boveda are suitable for this purpose, for example. The ingenious technology keeps the relative humidity constant at 62 %. Das Besondere ist, dass die Feuchtigkeit in beide Richtungen korrigiert wird.

Hygrometers, which are also used in cigar humidors, are suitable for keeping an eye on the humidity value. But cigar humidors themselves are not suitable for storing cannabis. Most humidors are made of cedar wood, which contains oils that can affect the taste and effect of your flowers. In addition, humidors usually contain sponges soaked in glycol to regulate humidity. However, this can lead to oversaturation.

Image: Golden Hygrometer

The Mary in a Bottle is a glass humidor made especially for cannabis flowers. Thanks to the hygrometer in the jar lid and the Boveda Hygro Pack in each jar, your grass will always have an optimal humidity of 62%, which you can control at any time.


High temperature often results in excessive humidity, which accelerates the breakdown of cannabinoids and terpenes. In general, make sure your storage container does not get warmer than 25.5 °C. Environments between 25.5 and 30 °C are best for the growth of mould and mildew.

Not a good environment for your weed is the fridge. Opening and closing the fridge causes temperatures and humidity to fluctuate, increasing the likelihood of mould and bacteria.

The freezer is also by no means a suitable place to store cannabis flowers. This is because the severe cold makes the trichomes brittle or they can be destroyed more easily.

Optimal temperature is below 20-22° Celsius

Image: Digital hygrometer 2

The 1000ml & 2000ml variants of Mary in a Bottle are particularly popular with growers due to their large capacity. In addition to a humidity display, they also have a temperature display.


New research shows that besides chemical composition, light energy is an important factor for quality. The more light a plant crop can store, the higher its quality. Fresh vegetables and sun-ripened fruits contain a lot of light energy, the same applies to cannabis flowers.

Various studies visualise impressively how violet glass protects the quality of food in contrast to conventional glass or plastic. A cherry tomato showed clear microbiological changes after seven months of storage in white glass - stored in violet glass, the tomato retained its red colouring and also showed no traces of drying. A similar result was observed when chives were stored for two months: while chives stored in brown and white glass lost their smell and colour, they remained much better in the violet glass.

This proves that not only the optimal cultivation of cannabis plants is important for obtaining perfect flowers, but also the storage to preserve the quality of the products produced.

Interview with CIA-TV at the Mary Jane in Berlin.

Bild: Cannabis richtig aufbewahren und lagern

Comparison of a cherry tomato after seven months of storage in a white jar and a violet jar.