Hemp cultivation has evolved significantly over the years, and with it, the techniques for harvesting and drying have also seen substantial advancements. Proper harvesting and drying are crucial steps in the cultivation process as they can greatly affect the quality and potency of the final product. In this blog post, we'll delve into different harvesting and drying methods for cannabis, helping both novice and experienced growers make informed choices. For this blog we will focus only on hemp grown for cannabinoids (mainly CBD or CBG) and terpenes. Harvesting and drying, or retting, of fiber hemp is a very different process which we will cover in an upcoming post.
When to Harvest
Once the fall weather begins to set in, it is time to start harvesting. Harvest season for high cannabinoid hemp can take place anytime from mid-September until mid-November. This depends on when the hemp was planted, hours of daylight (which stimulate the plant to flower), and the specific variety of hemp being grown. There are many subtleties which determine the exact moment when a plant is ready to harvest. This timing is highly subjective, takes some years to develop an eye for, and depends greatly on each individual grower's specific end-goal for their crop. Suffice it to say that we are looking to have plump, firm flower buds which are not past their prime and have no mold or other damage. Now, on to harvesting.
There are a variety of methods to harvest but the following encompass the 3 general ways harvest takes place.
Hand harvesting involves carefully cutting each cannabis plant by hand using sharp pruning shears or loppers. This method allows for precision in timing and minimizes damage to the plant. It is ideal for small-scale growers, and those who want to ensure the highest quality harvest.
Machine harvesting is efficient for large-scale cannabis operations. Specialized equipment, like trim machines, can rapidly cut and collect cannabis plants. While it's faster, there is a risk of increased plant damage and lower overall quality.
Some growers prefer to first selectively harvest mature buds while allowing smaller buds to continue growing on the plant. This technique can result in multiple harvests from the same plant, maximizing yield, but can be more time intensive.
Drying is a time-sensitive and critical piece to ensuring that a quality harvest is preserved for sale or processing. The five elements necessary for a proper drying set-up are: an enclosed space, temperature control (to force the plant material to desiccate), air circulation (to move moisture away from the plants), humidity control (to remove humidity from the air in the drying space), and darkness (to prevent sun bleaching and discoloration). Now lets explore a couple variations on this.
Hang drying is a traditional and widely used method. It involves suspending harvested whole plants or branches upside down on strings, netting or some other structure. The slow drying process preserves terpenes and cannabinoids, enhancing flavor and potency. It allows the grower to get the crop out of the field fast, especially when harvesting, and hang whole plants to dry all at once.
Rack drying involves placing harvested clipped buds on drying racks or screens. It offers better airflow than hang drying, reducing the risk of mold and speeding up the drying process. This is more labor intensive upfront but saves time clipping buds on the back end.
Quick drying can be used when time is limited or the harvest is very large. Plants are often machine harvested in this scenario. The resulting plant material is dried using heat and high airflow. Large belt dryers that have been used in the hops industry have also been used successfully for this method in the hemp industry. However, this method has its draw-backs. The aggressive handling of machine harvesting and high heat drying may compromise flavor, potency and terpene profile. This is often used for CBD isolate production.
Freeze drying is one more advanced method typically used by commercial operations. It preserves terpenes and cannabinoids exceptionally well, but requires specialized equipment and can have higher production costs associated with it.
As you can see, there are many ways to harvest and dry hemp. Harvesting and drying are critical steps in the cultivation process that significantly influence the final product's quality and potency. It is a good idea to plan ahead and have the right tools in place to get the job done effectively. Whether you're a small-scale grower or a large commercial operation, choosing the right harvesting and drying methods is essential for producing premium hemp. Experiment with different techniques to find what works best for your specific needs and enjoy the fruits of your labor with well-cured, high-quality hemp!