Though the Medicinal Cannabis Industry in Australia is relatively green, across the pond in Canada and the US, the industry has been growing for some time. Like for pharmaceutical facilities, designing and operating a Medicinal Cannabis Facility has its own pre-requisites and challenges. Many cannabis cultivators over-the-pond have gone through the whole process of designing and building a cannabis cultivation facility only to later learn that simple but costly mistakes were made.
To help you avoid this, we’ve pooled our accumulated experience from the Australian and San Francisco offices to bring you the top 5 Cannabis Cultivation Facility Design Tips to help you avoid similar mistakes.
1. Grow House Coverings
The first layer of protection is the cover material for the grow house. Although material technology has come a long way, please beware; not all coverings are created equal.
Given the sensitivity of the crop, its vital to select a covering material that provides a high level of ultra-violet (UV) light transmission. Any coverings that inhibit UV light transmission will restrict the production of cannabinoids. Diffused light that still allows the normal light spectrum is also important.
As well as providing sufficient light transmission, the covering should also be suitable for:
- acting as the first line of protection against pests, pollen and diseases such as powdery mildew or bud rot; and
- withholding the humidity levels in the greenhouse / grow house.
2. Employee Contamination Control
In older industries, such as Pharmaceuticals and Biologics, humans entering the facility are considered the primary source of potential contamination or cross contamination. In the Medicinal Cannabis Industry, this is no different. Strict gowning policies should be in place to inform staff, contractors and visitors about the acceptable level of gowning for each of the critical environments. Facility garments should also be regularly cleaned to prevent the build-up of dirt.
It is also wise to plan for appropriate decontamination airlocks to reduce the bioburden before entering critical environments. Airlocks are traditionally accompanied by hand washing facilities at the start of each entrance and gel type hand sanitation in the final stages.
Not only do the normal hand washing rules apply, but there should also be strict personal hygiene practices in place. Staff who are suffering from rashes or other ‘shedding’ skin conditions like eczema, will be required to declare these conditions at the start of the working day so that they may be assessed and reassigned to other duties that do not involve contact with the crop.
3. Sealed Environment
Completely sealed environments are preferred for large commercial Medicinal Cannabis cultivation operations. This can be achieved by applying slight positive air pressure that sweeps from the inside of the critical rooms, out towards the external environment. This “draft” can assist in preventing insect ingress. In addition, a stainless steel 60-micron mesh should be fitted to all openings – including filtration inlets, as insects can chew through the filter media. Most Medicinal Cannabis greenhouses are positively pressurised (to about +20Pa to the external environment).
In a sealed environment, consideration should also be given to the source of the air flow. All incoming or recycled air must be filtered and sterilised (e.g. by using UV sterilisers) to reduce the contamination risk from the external environment.
While HVAC equipment is expensive, using a “cheaper model” that doesn’t allow for a sufficient frequency of air exchanges will prove even more costly in the long run. If additional artificial lighting is used to extend the day length, or there is an extremely hot day, temperatures within critical areas can become highly variable and unmanageable; plants can get stressed and die, thus the importance of even and effective airflow distribution.
A balance can be achieved through:
- a constant airflow that promotes adequate CO2 dispersion and eliminates the possibility of air stagnation, humidity spikes or oxygen depletion;
- the use of the appropriate equipment to move air through the facility to control the humidity; and
- pruning or skirting the plants to remove lower branches to improve airflow.
To achieve an even air distribution, cultivators typically utilise inflatable (plastic) ventilation ducts under their grow benches that distribute air throughout the entire length of the grow house.
De-humidification is another critical design consideration. If moisture is too low, cuttings won’t root properly; too high and you’re looking at dealing with fungal problems. As an added complication, the levels of relative humidity will often substantially increase when the light deprivation systems are deployed.
It is well known that at different stages of cultivation, Medicinal Cannabis will require different environmental conditions in order to flourish. First and foremost: consider the unique requirements of your different grow rooms and plan accordingly.
If you would like some help designing your facility, please contact us.
If you would like to read more about Medicinal Cannabis-related topics, you might also be interested in the following blogs: