Humidity plays a huge role in the quality of cannabis post-harvest, as well as its lifespan once in the jar. Properly cured and stored flower can remain a sensory smoke show of flavor, smell, and effect long after it's sold. However, if moisture levels are off during the curing process or while being stored in the jar, even the highest-grade flower at harvest can fall victim to mold when too wet and harsh and degraded trichomes when too dry.
Like all good things in life, dank weed is ephemeral. But there are things we can do to slow its inevitable roll to the great beyond. Whether you're a home grower with a heap of harvest or a customer looking to make the most out of your dispensary run, it's essential information to know how humidity will affect your cannabis during and after the curing process.
Keep scrolling to learn about the complexities of maintaining humidity, or skip ahead to the best humidity packs for weed.
Cannabis and humidity: relative vs. ambient
There are two types of humidity to consider when curing and preserving flower. Relative humidity refers to managing the humidity levels of the flower inside an airtight container. Ambient humidity refers to the humidity of the room outside the jar.
The curing process occurs after the drying process. Freshly dried nugs are placed in airtight containers for 2 – 8 weeks, with the ideal relative humidity inside the jar between 55% and 65%, according to the American Society for Testing and Materials (ASTM). To learn how to cure cannabis, check out our step-by-step guide.
The purpose of curing is to stop the loss of moisture and develop the buds to their utmost potential. According to Ed Rosenthal, a cannabis legend, “Curing is an art and should be tried with small batches first. The flavor becomes much more complex and refined, gaining in depth as well as in variation of bouquet. Like very good aged wine, there is something unique about a well-cured crop that any aspiring connoisseur should experience at least once."
Since cannabinoid synthesis continues after harvest, the drying and curing processes can be as important as the growing process when it comes to the final product. Not only does a proper cure yield flower with a higher THC percentage, but it also stops the degradation of volatile compounds — like terpenes — that shape your experience with the plant, creating better tasting and smelling flower with a more potent high.
The best humidity levels for curing cannabis
To cure weed, growers loosely pack buds into Mason jars, seal them, and store them in a dark, cool place. Relative humidity should remain around 60%, which can be monitored using a hygrometer. Over the next weeks to months, growers "burp" the jars multiple times daily to release oxygen. Humidity levels are controlled using any number of tactics, from intuitively knowing what the flower should feel like to employing products like weed moisture packs.
Growing weed is an art form subjective to the person who grows it. It's a thing of patience, care, and personal preference. “It's a hundred percent intuitive on our end," said Joey Gothelf of WildLand Cannabis, an award-winning regenerative farm in Mendocino, California. “I usually just monitor moisture by feel."
He added, “The nugs shouldn't be able to crumble easily with two fingers. That's how I test the dryness. If I roll it between two fingers, and it crumbles easily into dust, that's too dry. But if it has a little bit of a chew, a little bit of a squishiness, but not too much, that feels right."
Walt Wood, a master grower and co-founder of Sol Spirit Farm, relies on experience, saying, “To me, curing actually just means evening out the moisture so the flower can undergo a microbial transformation, sort of like yogurt or something like that," he said. To tell how the cure is going, “I just reach in a bin and do a gentle 'touch touch,' and I'll know."
The best humidity packs for weed
While master growers rely largely on intuition to achieve the perfect cure, humidity packs like Boveda and Boost are tools created to regulate moisture during the cure and preserve the flower after jarring.
The way these packs are engineered allows purified water to be released into the jar when needed, supposedly eliminating the need for burping the jars during curing and providing peace of mind for the grower after they send their flower into the world.
The most popular humidity packs on the market are Boveda and Boost, and both work similarly.
Boveda packs control humidity using a salt and water solution that creates a “monolayer shield of purified water over the trichome," according to the Boveda website. They have a large presence in the sun-grown craft farm community, a group that takes their terps extremely seriously. They are generally regarded as leaders in the humidity pack space.
Boveda packs come in a number of sizes to suit any amount of cannabis. For example, "Size 1" would be appropriate for a single pre-roll tin, while "Size 320" would be appropriate to control humidity on a black and yellow bin during transport for a distribution company. The brand also offers “Home Grow" and other kits that include a number of packs, as well as metal C-Vault storage containers.
Boost brands its packs as “salt-free, two-way humidity control." They use a blend of water and plant-based glycerin to essentially do the same thing as Boveda packs. It's another big name in the space and is regarded as similarly effective.
Boost packs are available at 55% or 62% relative humidity in a number of sizes that clearly dictate how much cannabis they are for, like 8-gram, 4-gram, and 67-gram packs.
Professional grower tricks
Despite the popularity of weed moisture packs, most of the farmers I spoke to were on the fence about their effectiveness, preferring to opt for simple, old-school tricks when it comes to curing.
“The humidity packs might be garbage, but I don't really know," said Wood. “If I want to bring my flower up to humidity because it got a little dry, I just put a couple of drops of water in there, you know, a little bit of moisture. But you have to be careful because putting too much is really easy, then you go swinging the other way."
“If it's dry, nothing beats the tortilla," adds Jen Proccaci, co-founder of WildLand Cannabis. “It's an old-school trick. You put a piece of corn tortilla in the bag. It moistens up the weed, and the tortilla turns hard as a rock."
How to keep cannabis flower from degrading
While the cure is an art form in and of itself, keeping weed fresh mostly comes down to keeping the flower out of conditions that degrade trichomes. The biggest offenders? Heat, light, and humidity.
In the current market chain, growers deal with the issue of their flower degrading during transit or at the dispensary before the customer even has a chance to buy it. For this specific issue, humidity packets come in handy.
“Most of those humidity pack products are good for when you're shipping it out, and you want to make sure that it doesn't dry out when it's going down to LA or something," said Wood. “After it gets to the dispensary, you know that it's going to be sitting on a store shelf out in the sunshine somewhere," he said.
It's good to keep in mind that the flower you buy could have already been through a lot by the time it gets to you. This makes it all the more important to store and care for it correctly once you bring it home.
To make your flower last as long as possible, simply keep it in a cool, dark environment with moderate humidity. Think wine cellar, but weed cellar. Extracts and edibles should be kept in the fridge. Cannabis flower should be kept at around 60% relative humidity and out of any kind of light.
Editor's note: Weedmaps does not get affiliate revenue from the brands recommended in this article. All products are chosen independently by the author. The only influence Weedmaps News is under is weed.