◆ Storage
How to Store Cannabis Flower: Humidity, Light and the Jar Myth
· 7 min read
A cartridge is oil in a sealed chamber and is fairly forgiving. Flower is dried plant matter with its active compounds sitting on the outside of it, exposed, which is why it changes so much faster — and why the container it lives in matters more than almost anything else you do with it.
What is actually degrading
| Cause | What it does | How fast |
|---|---|---|
| Air | Oxidises THC toward CBN — heavier, sleepier, weaker | Weeks to months |
| Light | UV breaks cannabinoids down directly. The single worst factor | Days in direct sun |
| Dry air | Terpenes evaporate; the flower goes brittle and harsh | Weeks |
| Damp air | Above about 65% humidity, mould becomes a real risk | Days, in the wrong jar |
| Handling | Trichomes are brittle and rub off onto fingers and grinders | Immediately |
Four rules, in order of impact
- Airtight glass, filled reasonably full. Glass is inert; plastic carries a static charge that strips trichomes off the flower and holds odour from whatever was in it before. A jar with a lot of empty air in it is a jar of air slowly oxidising your flower.
- Dark. A cupboard, not a windowsill, and not a clear jar on a shelf. UV does more damage faster than anything else on the list.
- Cool and steady. Room temperature is fine. What is not fine is a cycle — warm afternoons and cold nights drive moisture in and out of the buds repeatedly.
- A humidity pack. The cheapest single upgrade available, and the only one that holds a range rather than hoping.
How long it actually keeps
- Up to six months stored properly: barely changed, still aromatic.
- Six to twelve months: noticeably flatter on the nose, still perfectly good to use.
- A year or more: more CBN than it started with, so heavier and sleepier, and most of the strain's character gone.
- Badly stored — a plastic bag on a sunny shelf — can be past its best in a fortnight.
Flower does not become unsafe with age; it becomes generic. The exception is moisture: anything that smells of ammonia or hay, or shows grey fuzz rather than white trichomes, goes in the bin without debate.
Frequently asked questions
- What humidity should cannabis be stored at?
- 59 to 63% relative humidity. Below that the terpenes evaporate and the smoke turns harsh; above about 65% you are risking mould. A two-way humidity pack holds the range without you having to check.
- Is a mason jar good for storing weed?
- Yes — airtight glass is the right answer. Glass is inert, where plastic carries a static charge that strips trichomes off the flower. Keep the jar reasonably full, because a jar with lots of empty air in it oxidises what is inside.
- Can you freeze cannabis?
- You can, and you should not. Trichomes turn brittle at freezing temperatures and break off at the slightest handling — you lose the part carrying both the effect and the smell. The fridge is worse, because condensation forms every time the jar comes out.
- How long does flower stay fresh?
- Around six months with little change if it is stored in dark airtight glass at the right humidity, and up to a year while still being good. Past that it turns heavier and sleepier as THC converts to CBN, and most of the strain character is gone.
- Does cannabis go bad?
- It fades rather than spoils — weaker, blander, sleepier. The one genuine exception is moisture: anything smelling of ammonia or hay, or showing grey fuzz rather than white trichomes, should be thrown away.
- What is the worst thing for storage?
- Direct light, by a distance. UV breaks cannabinoids down faster than air, heat or handling. A clear jar on a sunny shelf is the single most damaging thing you can do to flower.
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