Cannabis Dry and Cure Humidity Chart: Target RH by Stage
See the target RH for every stage: 55 to 65% while drying, 58 to 62% while curing, and 55 to 62% in storage, plus fixes for common humidity problems.
The target most growers land on for drying cannabis is 60% relative humidity at 60°F, held steady for 7 to 12 days. That number matters to you as a buyer because the cure is what separates flower that smells like a pine forest from flower that smells like hay. If a seller rushes the dry, no strain name on the label fixes it.
Cannabis Dry and Cure Humidity Chart: Target RH by Stage
When I open a bag, I'm not really judging the trim. I'm judging whether the cure held. Here's what that looks like in practice, and how to use humidity numbers to decide whether a listing deserves your money.
Why the drying humidity number reaches your bag
During drying, water leaves the flower and chlorophyll breaks down. Do it too fast and the outside crusts while the center stays wet, which sets up mold. Too slow, above roughly 65% RH, and botrytis and powdery mildew get a foothold. Go too dry and terpenes evaporate along with the moisture. Buds turn brittle and the smoke gets harsh.
Commercial producers track water activity, or aw, alongside RH. Below about 0.65 aw, mold growth stalls. Most cured flower sells in the 0.55 to 0.65 aw window, which lines up with 58 to 62% RH at room temperature.
The parameters worth memorizing
- Drying room: 45 to 55% RH, 60 to 70°F, 7 to 12 days, dark, with gentle airflow. Plenty of growers run a flat 60/60 instead.
- End of dry: small stems snap instead of bending. Big stems may still flex a little.
- Curing jars: 58 to 62% RH is the sweet spot. Aim for 62% if you're storing for months, 58% if you'll smoke it within a few weeks.
- Above 65% RH in a sealed jar: burp daily and watch for an ammonia or sweet rotting smell.
- Below 55% RH: the cure has stopped. Rehydration helps texture, not much else.
How to vet a seller's cure before you pay
- Ask if humidity packs ship with it. Two-way packs holding 58 to 62% are the clearest signal that someone understands cure. Boveda and Integra Boost are the common ones.
- Look for a harvest date. Flower under four months old usually means the cure wasn't a salvage job.
- Squish test. Properly cured bud gives slightly under pressure and springs back. If it crumbles to dust, it was over-dried.
- Read reviews for smell words. Buyers who mention hay, grass, or "no smell" are describing a failed dry, regardless of strain.
- Distrust flower that feels damp. Wet weight means you're paying for water, and shipping in a sealed bag at high humidity is a mold risk by the time it lands.
Pitfalls that show up in online listings
Plastic bag shipping is the big one. Mylar or a glass jar with a pack holds humidity; a ziplock in a bubble mailer does not, so buds arrive at whatever the weather decided. Photos taken the day of harvest mean nothing about how the flower arrives.
Beware of "pre-cured" claims with no numbers attached. A brand that can't tell you its target RH either doesn't measure it or knows the answer is unflattering.
Finally, mold. White fuzz, gray webbing, or a basement smell means toss it. Don't try to re-cure moldy flower and don't mask it with citrus peel or bread. That adds moisture and invites more mold. If your flower is only dry, a humidity pack fixes the feel in a day or two.
Storing what you buy
Glass jar, airtight, out of light, one 62% pack, 60 to 70°F. Burp weekly for the first couple weeks if it's still curing. Skip the fridge, since condensation on the way in and out does more damage than a stable shelf. The freezer is for long-term extract storage, not flower you plan to smoke this month.
None of this is exotic. It's just the difference between a seller who measures humidity and one who guesses.