Cannabis Storage Conditions: Temperature and Humidity
Store cannabis at 59-70°F and 55-65% relative humidity in an airtight, light-blocking container. Here is how temperature and humidity protect potency.
Shoot for 58 to 62 percent relative humidity (RH) at 60 to 70°F. Inside that window the cure keeps moving. Above 65 percent you are handing mold and yeast a place to grow. Below 55 percent the slow breakdown of chlorophyll and sugars stalls, and it does not restart once the flower is that dry.
Cannabis Storage Conditions: Temperature and Humidity
Why the range is this tight
Curing is not just drying. It is a slow enzymatic and microbial process that eats leftover sugars and pigments, which is why bud that smelled like lawn clippings at day three can smell like the strain it actually is at day thirty. That process needs some moisture to run. Terpenes, meanwhile, are volatile, and they leave with the water when things get too dry. You are balancing two things that pull in opposite directions, and 58 to 62 percent happens to sit where both survive.
Dry before you jar, always
Humidity inside a jar only reflects what you put in it. If the flower goes in wet, the jar reads 70 and no humidity pack will fix that. Get the dry right first:
how to maintain humidity in cannabis jar
- Small stems snap when bent, larger stems bend but do not break clean
- Buds feel dry and slightly crisp outside, still a bit spongy at the core
- Roughly 10 to 12 percent moisture content by weight, if you weigh
Ten to fourteen days of drying at 60°F and 55 to 60 percent RH in the room is a common target. Faster than that and you lock in the hay smell.
Optimal Cannabis Storage: 62 Percent Humidity Guide
Burping schedule
Fill jars about three quarters full. More than that and you trap pockets of damp air against the glass.
- Week one: open each jar twice a day for 5 to 10 minutes
- Week two: once a day, 5 minutes
- Week three onward: once every few days, or whenever the jar reads above 62
If a jar reads 66 or higher after a burp, dump the flower onto a tray for an hour or two and re-jar it. Do not wait to see if it settles.
Measure it instead of guessing
Small digital hygrometers cost a few dollars and are worth buying in pairs. Calibrate them with a salt test: a sealed container with damp table salt should read 75 percent RH after 12 hours. If yours reads 68, you know your real curing number is 7 points off. Leave the meter in the closed jar for an hour before trusting the number.
Humidity packs help, but they buffer
Two-way packs hold a target and correct small drift in either direction. A 62 percent pack is the usual choice for curing, and 58 percent for longer storage or for flower you plan to vape. What they do not do is dry out wet flower. They also have a limit, so a jar sitting at 70 percent will overwhelm a single small pack.
Water activity, the number labs use
Regulators in several states cap cannabis flower at 0.65 water activity (aw), and most commercial growers target 0.55 to 0.62. Water activity is not the same as RH, though the two track together. It measures the free water microbes can actually use, which is why it is the figure that shows up on a compliance test.
Temperature, light, and jars
Keep jars in a dark cabinet at 60 to 70°F. Warm rooms push terpenes out of the flower and into the headspace. Glass beats plastic because it does not hold odor or static. Label each jar with the strain and the date you jarred it, because you will not remember in six weeks.
Signs something is off
- Hay or cut grass smell: dried too fast or too far, cure has stopped
- Ammonia or sour note: too wet and running anaerobic, burp more and dry it back
- Buds that crumble to dust when squeezed: under 50 percent, terpenes are gone
- Fuzzy white or gray patches: mold, toss the affected material and check the rest
How long to cure
Two weeks is the floor. Four to eight weeks is where most strains show what they actually have. Once you are happy with the smell and taste, dropping to 58 percent for storage slows further change and keeps the profile where you left it.