Moisture is one of the biggest downfalls of grows of all sizes, from small craft farms to large-scale operations, but it’s also an unavoidable part of the experience. Fresh cannabis typically clocks in at around 75 percent moisture — moisture content that can attract mold, mildew, and bud rot. This makes setting the right humidity for drying cannabis crucial for a good outcome.
As a commercial cannabis or hemp grower, what can you do to control your grow’s humidity for drying weed? Keep reading to learn how to better control humidity and your flower’s moisture content.
Humidity and moisture: What problems do they cause?
There are two main ways humidity comes into play in a commercial cannabis grow: the environment in which the cannabis or hemp is grown, and the moisture content of the plant material itself. Managing both these factors is important because excess moisture and humidity:
- Lead to contaminant growth. If your grow room is too wet or humid or the plant material itself is too wet, your cannabis or hemp flower is at risk of developing harmful mold and mildew. These contaminants develop easily, and once they take hold, they are nearly impossible to remove.
- Make flower unable to be smoked, in most cases. Flower contaminated with mold cannot be smoked, especially for medical cannabis patients who are particularly sensitive to contaminants.
- Result in bud rot. Cannabis grows with too high humidity or moisture and can also exhibit signs of a condition called “bud rot.” Bud rot is a type of fungus called botrytis cinerea that develops inside flower early on and appears closer to the harvesting stage. This highly contagious fungus spreads easily throughout the entire plant and can quickly leap to other plants.
Can humidity be too low for successful cannabis cultivation?
Tightly controlling wetness, humidity, and moisture conditions during the growing, cannabis drying, and cannabis curing processes keeps fungal growth at bay. But there is such a thing as cannabis that’s toodry.
Too little humidity or moisture content can make smokable cannabis and hemp flower brittle, where it crumbles in your hand instead of grinding up nicely. There is a common misconception that cannabis can be “rehydrated,” but this process can damage trichomes and subsequently plummet the cannabinoid content of your flower. Notably, though, extractors (such as those making concentrates or vape oils) benefit from ultra-low flower moisture levels, as this results in higher cannabinoid and terpene yields.
What’s the ideal moisture content for cannabis and hemp flower?
If both too-wet and too-dry conditions have undesirable results for smokable cannabis and hemp flower, is there such a thing as ideal moisture and humidity levels? Yes — and here they are for each stage of the process:
- Seedling stage: 65 to 70 percent
- Vegetation stage: 40 to 70 percent
- Flowering period: 40 to 50 percent
- Cannabis drying stage: 50 percent in the drying room
- Once cannabis is dried and cured: At most 15 percent in the flower
Here are more details about the right humidity for drying weed during each stage.
Seedling, vegetation, and flowering stages
The humidity level in the grow facility changes depending on whether your crop is at the seedling stage, vegetation stage, or flowering stage. A humidity level between 65 percent and 70 percent is recommended for the seedling stage. This figure should be lowered by five percent per week during vegetation while still remaining between 40 and 70 percent.
Generally, the flowering period can thrive in humidity levels between 40 percent and 50 percent. Some may choose to lower humidity once more during the last flowering stage.
Cannabis drying stage
During the critical cannabis drying stage, moisture content is brought down from the plant’s natural levels. As the cannabis dries, the moisture comes off the plants and lingers in the air, making managing humidity in the drying room of utmost importance. Generally, growers try to keep humidity levels at around 50 percent in the drying room.
Once cannabis is dried and cured
As for the moisture content of the flower itself, cannabis growers typically strive for no more than 15 percent moisture content once the cannabis drying and curing process is complete. Cryo Cure’s patented cannabis drying and curing processes stabilize flower at between 8 percent and 12 percent moisture content — just enough to keep it fresh while lowering the chances that mold, mildew, and fungus thrive.
How does humidity affect the drying stage?
Environmental factors including air movement, transpiration, and relative humidity influence the drying stage. These factors directly pertain to water content and shape your flower’s water activity level (how much water is available in the flower for biological reactions to occur), and they all have an effect on each other. Their interrelated nature makes it highly important to achieve consistent conditions in cannabis drying rooms. This way, your product achieves the ideal humidity for drying weed of at most 15 percent, and a water activity (aW) level of at most 0.6.
Three factors related to humidity especially shape the drying stage:
Drying room design
The nature of drying rooms may make it harder for you to achieve your humidity and water activity goals. In particular, variations in relative humidity across the different parts of a room are common. Flower that dries in different parts of the room may thus reach different moisture levels, resulting in uneven quality. Proper HVAC and dehumidification equipment and setup can mitigate this problem.
Plant size
It’s best practice to intersperse larger buds and plant sections with smaller cuttings. Larger sections are more moist, so bunching them together often reduces airflow and increases the humidity around these weed plants. Varying bud and cutting size across your setup lessens the likelihood of overly humid microclimates within your facility.
Drying speed and methodology
Dry your cannabis too quickly, and its flavor, aroma, and color will be diminished, leading to dissatisfied customers unlikely to buy your product again. Dry too slowly, though, and contaminant growth is likely. Opting for solutions other than standard hang drying helps you combat environmental fluctuations that could result in problematic drying speeds.
What other environmental factors impact cannabis quality?
While humidity and moisture content are significant issues for cannabis growers, this is far from the only factor that needs to be monitored and carefully controlled. Temperature, air, and light also play a role in cultivating, drying, and curing quality cannabis that does not suffer from issues with quality like moisture-driven problems and THC degradation.
- Temperature: Too-warm temperatures kickstart decarboxylation, boil off precious cannabinoids and terpenes, and impact humidity. Moisture has the chance to thrive when coupled with higher temperatures.
- Air: Exposure to oxygen drives the degradation of THC and other cannabinoids and terpenes, resulting in a less potent consumption experience. Circulation and ventilation in the growing and drying environment are also of vital importance, as they help mitigate humidity and control moisture levels.
- UV rays: Dark rooms and containers are best during the cannabis drying and curing process. Exposure to UV rays accelerates the breakdown of all organic matter, cannabis included.
How Cryo Cure helps you control moisture levels
As we established in this blog, humidity and moisture content are crucial to a successful cannabis harvest. Cryo Cure is an important tool to help you mitigate these factors before they become a problem in your cannabis or industrial hemp growing facility — and achieve the ideal humidity for drying weed.
Cryo Cure’s patented technology preserves that “fresh from the farm” feeling without any of the moisture levels prevalent in live plants. By freeze-drying wet cannabis, THC levels are stabilized as the cannabinoid and terpene-rich trichomes are perfectly preserved in a way that no other cannabis drying or curing process can achieve.
By skipping the hanging phase of drying, Cryo Cure mitigates one of the most volatile variables in the cannabis drying and curing process: time. Not only does this get your products onto the shelf faster, but shortening the window can help you avoid many of the problems triggered by prolonged exposure to the elements, including moisture-related bud rot and mildew growth.
Our patented process preserves between 8 percent and 12 percent of your flower’s moisture content, but you can customize the settings for strain-specific outcomes or any other desired end. This includes extraction-specific settings that can bring down moisture content as low as 1 percent, preferred for maximum cannabinoid and terpene yield.
As you plan out your cannabis or industrial hemp grow operation or explore ways to upgrade your facilities, keep humidity and moisture content control central to your strategy. View the Cryo Cure models page to review your options, and contact Cryo Cure to discuss how to bring our machines to your facility.