AUTOMATION

By Clayton Stewart

It may sound like a daunting task to harvest over 2,200 pounds (~100 kg) from 800 to 900 plants and return the site to clean and sanitized, in less than 24 hours, but with the right type of automation and labor efficiency, savvy commercial growers do this on a daily basis.

Compared with the preceding cultivation stages, the harvesting stage is labor-intensive and often involves many bottlenecks in human processing capabilities. When harvesting hundreds to thousands of plants, even the distance and time spent traveling between the garden and harvesting spaces reduces efficiency.

Automating Climate

For drying and curing rooms, strategically placed probes can provide information on temperature and humidity.

Climate monitoring equipment such as Bluetooth and Wi-Fi-enabled hygrometers are indispensable tools for remote viewing and historical tracking of relative humidity and temperature data in the drying room. These wireless hygrometers, although more expensive than conventional digital ones, offer users the option to view and track environmental criteria without disturbing drying, curing, or storage containers or the need to be in the drying room. With a typical temperature accuracy of ±2°F (~1°C) and relative humidity accuracy of ±3%, these tools are best applied when combined with controls for HVAC, humidification, and dehumidification.

In commercial settings with multiple units working in concert to regulate environmental set points, it is critical to have an understanding of fresh-product, moisture-load expectations, that is, how much water must be removed from the atmosphere to facilitate drying, and to communicate these specifications to HVAC engineers for proper sizing and calibration of the dehumidification and humidification units.

In the process of cooling air, air conditioners remove moisture and provide additional dehumidification. Low humidity can be corrected by pausing dehumidification. The relative humidity rises naturally through the transpiration of water vapor from the plant material.

Propagation

Propagation is a baby cannabis plant’s chance at becoming a mature, fruit-bearing female, and typically requires a steady human hand to select a suitable cutting for cloning, or germinate a seed, or cultivate tissue in nutrient culture. Micropropagation is a more precise method of stem propagation by which a thumb-nail-size tissue cutting is collected and cultivated in a petri dish. Minimal changes to infrastructure to include laminar flow hoods and HEPA-filtered HVAC can provide a sufficiently clean environment for tissue culture propagation to reap the benefits of reduced chance of microbial infection, reduced labor, and reduced space requirements.

Jack Ford of Agronomix Software, a company that helps plant breeders, crop researchers, and agronomists with yield increases and data management, says of its latest transplant robot: “With simple automation during propagation, a grower could experience a 25% gain in production. Automating the full process could lead to a 50 to 70% gain in efficiency” (Greenhouse Canada Magazine, June 14, 2019).

Labor, Time & Space Saving Tools

To eliminate most of the aisles in an indoor garden, growers rely on a rolling pallet bench, also referred to as a Dutch tray table system. While the legs of the table remain in place, the top rolls from side to side. Most of the time the tabletops are next to each other. But there is enough room for an aisle when the top is rolled to one side. To make the next aisle, the next tabletop is moved. Single aisles provide more canopy space and ensure that all light reaches the plants.

Portable conveyor belts are easy to set up and save labor by transporting equipment, plants, tools, and other items from one location to another without the use of labor. For instance, buds or branches can go directly from the harvest room to the processing center without people or vehicles transporting it. It may allow for elimination of walkways.

Picking

Harvesting operations are completely dependent on site conditions, plant spacing, cultivar(s), growth method (with/without trellis), plant size, and total plot area.

To automate equipment for harvesting while avoiding unnecessary downstream processing, the more centralized the buds are toward the top of the plant, the better. This allows for the efficient separation of the colas from the stalks and branches.

Bucking

In an industrial setting, rack drying on perforated baking-style sheets is more time efficient than hang-drying whole plants with their woody stalks and branches still attached.

First, buckers are used to separate the buds from the stalks. This eliminates the first bottleneck of harvesting. Automated buckers come equipped with hoppers that catch and funnel the buds to a desired location. Horizontal and incline step conveyors can take over from that point to direct the buds toward a series of trimming machines. Wherever there is no conveyor, simple transport utilities such as pallet jacks, loadable carts, trolleys, or lightweight electric utility vehicles can move bins of product. “Hand-bombing” and handling buds more than once during the harvest process are known contributors to inefficiencies in the industrial harvest department.

Sorting for Defects

Blueberry grading machines such as The Berry Class by Elifab Solutions use proprietary software to optically recognize defects in blueberries with up to 96% accuracy. This type of technology is adaptable to the cannabis industry and could automatically recognize mold-and fungus-affected buds during the processing of large harvests.

Sanitation

UVC light exposure is another effective way to reduce bioburden and treat surface pathogens such as powdery mildew, which can contribute to a host of other problems. UVC light exposure works by degrading microorganisms’ DNA. Aeon CleanLight, a company based out of the Netherlands specializing in UVC disinfection technology, currently offers a ballast system for industrial grow rooms that delivers effective doses of ultraviolet light without harming the plants.

Large-Scale Drying & Curing

During the drying and curing stages, regulation of temperature (heating/air conditioning), relative humidity (humidification/dehumidification), and air circulation is paramount. Thus, a purpose-built cannabis drying and curing chamber requires all the aforementioned components, as well as Good Manufacturing Practice (GMP) design and compliance, in order to compete with conventional drying and curing spaces in industrial settings.

Systems such as the Cannatrol Dry/Cure Box, Darwin Chamber, and Conviron Walk-In Room offer custom-designed chambers that can effectively reduce drying and curing times by actively managing temperature, airflow, and vapor pressure to encourage the consistent removal of moisture and preserve terpenes. This can allow users to home in on specific repeatable settings, depending on the cultivar. It is important to work with reliable engineer recommendations to determine the installation and calibration of these systems, as their performance will directly depend on the load and frequency of product being introduced.

Another technological application similar to these custom-designed chambers is the radiant energy vacuum dehydration (REV) system, which uses microwave energy and vacuum pressure to heat water and evaporate water molecules while retaining terpene content. Manufacturers claim the process is complete in several hours, with an output of about 26 pounds (12 kg) per hour of ready-to-use dried product.

Kiln Drying

Kiln drying is a technique used in large-scale commercial cultivation of a variety of herbs and agricultural products, such as lumber, tobacco, herbs, and cannabis. Kiln drying is utilized efficiently by hemp-flower growers, who are not interested in preserving terpenes. The primary advantage of kiln drying is the capacity to dry large quantities quickly in an enclosed space with controlled heat and rapidly circulating air, using temperatures up to 95°F (35°C). However, these high drying temperatures result in the loss of terpenes.

Freeze Drying

The Cryo Cure machine uses freeze-drying to rapidly and consistently preserve up to 1,200 pounds (~545 kg) of fresh flowers with no shrinkage, intensified color and flavor, and stabilized THC, terpenes, and trichomes in just a day, making it a great companion for live extract processing.

Processing Pre-Rolls

While a lot of commercial cannabis is destined to be sold in flower form, increasingly more large-scale producers have moved into automated processing of pre-rolled joints. Hand-rolling joints is laborious and time-consuming. Using automation, whole big buds, smalls, and shake is run through bulk grinders and packed into hundreds of cones in a matter of minutes.