By Chris Bayley
Just like growing cannabis, harvesting your crop is an art as much as it is a science. All the physiological processes a plant goes through while it is growing and drying are quantifiable. The awareness growers gain of these processes over time, coupled with an eye toward artisanship, are what will allow for the complete genetic expression of your crops.
The hard work of bringing a successful crop to fruition will be in vain if producers do not follow through with the proper harvesting protocols. In this article, we will be covering harvesting procedures, which include pre-harvest trimming (a.k.a. green trimming), drying, post-harvest trimming (a.k.a. dry trimming), curing and a special processing technique called D.R.F.C.T.
As covered in the September issue of Marijuana Venture, once you have determined that your plants are at their peak floral development, it is time to begin the harvesting process. The first decision to make will be to either remove or leave the non-resinated leaves. These leaves are often referred to as sugar leaves, fan leaves, sun leaves, etc. For our purposes, we will refer to them as non-resinated leaves. To be clear, these leaves do have cannabinoids; however, the levels are negligible. If the plants are being grown naturally and the leaves are free of residual synthetics, consider tapping into existing markets for juicing fresh leaves for health-related purposes. If you have no interest in marketing your non-resinated leaves, at least consider recycling them through a compost pile or worm bin. Just be sure to follow state regulations regarding disposal of waste products.
If you decide to remove the non-resinated leaves pre-harvest, it is best to do this while the plant is still upright, and using your hands. A considerable amount of time can be used doing it this way, and it’s also easier than using scissors. This technique requires both hands. Begin by pinching or grabbing the upper-most non-resined petiole (leaf stem) on the branch. When hanging onto the branch or petiole, apply adequate pressure to control the branch without damaging any plant tissue. With your opposite hand, systematically work your way down the branch, snapping off the non-resinated leaves. If the branch is long enough, you may need to re-position your hand that is being used to stabilize the branch as you work your way down. Once a person becomes proficient at this technique, hours can be shaved off non-resinated leaf removal compared to using scissors.
Once you have removed the non-resinated leaves, it is time to begin the trimming process. The trimming process can be broken down into two categories. The first is done manually by hand, and the second is by using commercial trimming machines. There are two different options when it comes to hand trimming. Wet trimming takes place before the plants dry, and dry trimming takes place once the plants are done drying. We’ll come back to dry trimming later in the article.
There are a couple upsides to wet trimming. While the plant is still wet, the resin heads are tacky and pliable so they do not dislodge as easily and will remain intact. Another benefit with wet trimming is curb appeal. Cannabis that is wet trimmed has a distinct look to it that when dry, takes on bouffant-like characteristics. Wet trimming is fairly straight-forward. Once the non-resinated leaves are removed, simply trim the leaves covered in resin to the desired length and hang the plant upside down. Perhaps the only downside associated with wet trimming is that once the plant is cut, you have a 12- to 24-hour period of time to finish the process before the plant loses turgor pressure, making wet trimming next to impossible.
Another route that can be taken by way of wet trimming is to use commercial trimmers.
These machines are built to trim aromatic crops such as herbs and hops. They also happen to make quick work out of trimming cannabis. This method also gives the finished dried product an atypical look compared to hand trimming that retail customers will learn to recognize as machine-trimmed flowers. Like all trimming methods, there are positives and negatives. These machines are incredible time savers. If being used properly, they have the capacity to work through more than 20 pounds of bud a day. An experienced hand trimmer, depending on the strain, can trim through one to four pounds every day. The efficiency and time saved using a commercial trimmer when you have 25 pounds or more to work through becomes apparent when you crunch the numbers.
One downside when using these machines to trim cannabis is damage to the trichomes on the leaf. A percentage of trichomes will get smeared, making it useless for a dry sieving operation. All hope is not lost though; you can still process the leaf by means of diffusion, which can be used for edibles, tinctures, and topicals.
Let’s take a look at how to set up a commercial trimming operation. Visualize a linear layout of the operation. On one end is a team that will remove non-resinated leaves from the plants. As the plants get de-leafed, a member of the team will cut manageable pieces that are suitable for the trimming machine and place them on a receiving table next to the machine. The machine operator will feed the cut flowers into the trimming machine and will be responsible for keeping the machine in working order. The operator will usually have an assistant who places the trimmed flowers onto racks in the drying room. As you can see, this system is meant to work through trimming high volumes of cannabis, and the number of folks it takes to do this will depend on the size of the operation.
Drying room science
Plants breathe just like humans; that is, there is a gaseous exchange that takes place through what is called the stoma. Plants breathe in carbon dioxide and exhale oxygen — the exact opposite process for humans — and exemplifies one of the most important symbiotic relationships in nature. It is calculated that the total amount of water that exists in the atmosphere is cycled through plants, via the stoma, on a bi-annual basis. This gaseous exchange that takes place is how water and minerals are transported throughout the vascular system of the plant. Of interesting note, is that the density of the stoma development is interconnected to the levels of carbon dioxide in the atmosphere. The higher the CO2, a lesser response by a plant to develop the stoma. This would make for some interesting research pertaining to the benefits of an above-average CO2 atmosphere.
Of all the post-harvest steps a grower takes their plants through, the drying stage is far and away the most critical phase. The significance of this stage cannot be expressed enough. When it comes to drying cannabis, the name of the game is slow and steady. If plants are dried too fast, via high temperatures and low humidity, the stoma will prematurely close, increasing the odds of locking in a “green flavor.” When a plant is first cut, the metabolic processes do not immediately cease, and it is for this reason that a grower should strive to extend the drying process. This is done by keeping the humidity higher and the temperature lower. However, unfortunately, these are exactly the conditions that pathogens need to flourish. So unless you have the proper environmental control in place, this should not be attempted. For growers who have access to a subterranean environment, such as a basement, you will have the perfect place in which to attempt this higher humidity and cooler drying environment.
One of the best preventative measures at controlling pathogens during this critical time is the use of recirculating filter boxes with the incorporation of UV sterilizers. No harvesting, drying, curing or processing room is complete without them. Not only do they continually sterilize the air, but they also filter it, thereby reducing the volume of airborne adulterating contaminants. If the proper conditions exist, drying times can be expected to take anywhere from two to six weeks.
There are two common methods most growers use to dry their plants. One way is to use drying screens and the other is to suspend lines on which you can hang the plants. Both of these methods work just fine. The only noteworthy differences are that when screen drying, you end up with a compressed look on the side of the bud that is facing down. This can be prevented by periodically turning them; however, as the flowers dry, a certain percentage of trichomes will be dislodged through constant handling. Line drying is the least invasive out of the two because of the lack of handling needed between harvesting and packaging.
Some producers may choose the option of trimming their plants post-drying. Even when electing to go this route, substantial time will still be saved by removing the non-resinated leaves prior to harvest. Trimming post-harvest is referred to as dry trimming or manicuring.
In case you did not remove the non-resinated leaves at the time of harvest, you will need to decide how to address their removal at this point. There are two options on how to handle this. One is to simply have your trimmers cut all the leaf off at one time, and then separate the non-resinated leaf from the resinated leaf. If you elect to go this route, keep in mind that it can become quite tedious to separate all the little pieces of stem and non-resinated leaf. Keep this point in mind because if processors elect to charge their fees based on weight, you will want your trim to be as clean as possible.
The second option is to trim in two waves. The first wave of trimmers takes off the non-resinated leaf, then passes the flowers along to the second group, which trims off the resinated leaf. Once this two-stage system is perfected by your trimming crew, any extra time associated with passing off the flowers from one person to the other is negated by the time saved sorting the leaf. As a person gains experience at trimming cannabis, a definite artistic touch will come into play.
There are huge differences in floral formation between sativas and indicas. The main contributing factor to this is what is referred to as the flower’s calyx to leaf ratio. Calyxes are the ovaries on a female cannabis plant that build up through the flowering process, and gives a flower its overall shape. When it comes to picking the varieties you are going to grow, keep the calyx to leaf ratio in mind. For those of you who want flowers that trim really fast, a high calyx to leaf ratio will accomplish that goal. For producers whose goal is to process all the trim or possibly the whole crop, then a high leaf to calyx ratio may be in order.
For growers who would like to take their product to the next level — past what drying will accomplish on its own — curing your crop is the answer. The point of curing cannabis is to minimize certain inherent negative qualities while simultaneously enhancing its attributes — in this case, its terpene profile. There is a wide range of aromas in all cannabis strains that is made possible by a plant’s individual terpene profile. This profile will have varying ratios of terpenes, some of which can become lost in translation, or masked by chlorophyll, if not put through a curing process. The goal is to bring out these subtleties and increase the overall potential of the bouquet.
Another thing that will take place slowly over time in the proper curing environment, is the decarboxylation of THCA and CBDA into THC and CBD respectively. The process of decarboxylation happens through heat. It instantly happens when one is smoking cannabis, and why you can eat raw cannabis without getting high. Here is a tip for processors who are infusing alcohols and want to ensure full utilization of cannabinoids (please note that I-502 processors are prohibited from infusing alcohols). First, decarboxylate your plant material in an oven at around 200 degrees for 30 to 60 minutes. Next, submerge the product in a lidded glass jar with high-proof alcohol and place in the freezer. The higher proof alcohol you use, the faster and more complete the diffusion process will be. Let this steep for around a week. Experienced or not, always proceed with caution when trying out a new batch.
Up until the point of legalized cannabis production, most growers used brown paper bags and glass mason jars to cure their weed. For production growers, more commercial methods of curing will need to be employed. This will be in the form of climate-controlled rooms not unlike what you will use for drying your crop. The difference will be that your curing room will need to be completely sealed so you have complete control in manipulating the gaseous state within the room. With monitoring equipment, you can have exacting control over these processes and will know when your products are cured based off the collected data.
D.R.F.C.T (pronounced dry-fect) is an acronym that stands for “dried refined frozen collected trichomes.” It has been given to a particular process used in separating trichomes from the plant matter they’re attached to. In a nut-shell, the plant material to be used is frozen and run through a sieving machine. More on this later.
When it comes to extracting cannabinoid and terpene profiles, there are a myriad of choices available to the budding processor. There are basically four different methods of extraction. This includes infusion, in which lipids and alcohols are used; bubble hash, in which near-freezing water is used to separate the trichomes; gaseous extractions, which include butane and carbon dioxide; and dry sieving. Dry sieving is what has been used throughout time until more modern methodologies became available.
All of these forms really have their distinct purposes. Infusion is typically used when one wants to make tinctures for a sublingual application or when wanting to infuse liquids and foods. Gaseous extractions are used to purify and concentrate the cannabinoid profile into oils, shatters, waxes, etc. The oils in this method can also be used to infuse food and liquids. The oils and waxes made from this method of extraction are also fueling the use of vaporizers that come in many forms. This form of use has risen in great popularity over the last couple of years, especially in the method known as “dabbing.”
Dry sieving without using the freezing component is a great way to collect trichomes. In fact, when you are trimming a dried cannabis flower, you’ll notice that just through the handling of the flower and the motion made while using scissors, a pile of trichomes will begin to develop on the tray you’re trimming over. Trichomes will easily dislodge from plant material in a dried state and is another factor to consider when choosing the strain to grow.
The reason for adding a freezing component is to increase the efficiency of the process. If the temperature is not correct in the room you’re sieving in, the trichomes become pliable, making it more difficult in dislodging them from the plant material while losing a percentage to the equipment itself. Freezing the plant material prior to sieving, temporarily putting the trichomes into a crystalline state, makes them practically shatter off the plant material when tumbling through the sieving machine.
If the D.R.F.C.T process is performed correctly, and depending on the strain of cannabis being used, you can expect a finished product to equal a full melt hash normally made through water extraction methods. Quite possibly the biggest upside to this method that differentiates itself from other extraction methods, is that it is the only one to keep intact a complete terpene profile. The costs associated with developing a processing room for the D.R.F.C.T. method are minimal as compared to building out an explosion-proof room for operating a gaseous extraction system. To develop a processing room for dry sieving, you would want to build out a climate-controlled room and possibly a walk-in freezer depending on the scope of the operation.
As with seed selection and proper growing techniques, it becomes apparent how important post-harvest methodologies are in maximizing a plant’s full genetic potential.
Remember, stay focused and let it grow!
Chris Bayley operates a consulting company called Hortistructure, Inc. geared toward legal producers and processors. He’s also co-owner of the gardening store, Elemental Gardener in Tonasket, Washington.