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Prevention, air, and construction: main challenges for greenhouse hemp growing

In the ever growing commercial hemp industry, there are many challenges faced by commercial greenhouse operators. These challenges range from legal requirements, certifications, and facility guidelines. One of the top issues faced by the commercial grower are challenges that surface from the design and construction of the facility. Additionally, the impacts of overall design of the facility due to equipment installations and needs, and design, construction and build outs. 

In the design and construction challenges faced by commercial hemp growers and operations, there are three main areas of focus. These areas are Prevention, Air, and Construction (PAC). These areas should all be considered and addressed to meet the challenges effectively. All three are interlinked into the overall challenges faced by the facility.

Prevention
In the prevention of cross contamination and overall sanitation, there are some additional needs and concerns that make commercial hemp cultivation have challenges. These are employee decontamination areas, sealed environments, and greenhouse coverings. These three are regarded as the top concerns and challenges faced by the commercial grower. In the process of prevention within a commercial grow operation, operators should have some form of decontamination areas, a sealed environment, and have greenhouse coverings. 

These three areas are a must in proper sanitation and prevention of disease and pests. Having decontamination areas are essential to ensuring that no outside contaminants, pollutants, or pathogens get into the growing areas where sanitation is a priority. These areas should be regularly cleaned, disinfected, sanitized, and free from pests and diseases. When designing a greenhouse, a plan should be made for proper decontamination zones, or a grower risks having outside pests and diseases tracked into the grow room. Although greenhouses with direct access to the outside environment can be convenient, they aren't wise to have when growing crops that require pristine growing areas. The completely sealed environment should be preferred in commercial operations. This is also true within the hemp industry. The more controlled the environment is, the better able an operator is with controlling possible disease and pest outbreaks. When selecting greenhouse coverings, one should be aware that not all coverings are created equal. A covering that does not inhibit UV light is vital. Plants need these UV rays in order to grow and create energy through the process of photosynthesis. Coverings that inhibit UV light transmission are very detrimental to growing operations. Light should be diffused but still allow proper light spectrum to penetrate.

Air
Everyone knows that clean air for humans is important. However, the same can be said for plants. The environment the plants grow in should have positive air pressure, proper airflow, air filtration sterilization capabilities, humidity and vapor pressure deficit control, and the ability to control all aspects of ventilation and air flow through an HVAC system.

Scientific studies have shown that the use of positive air pressure in an indoor greenhouse environment is very beneficial. This kind of environment assists in deterring infestations of both pests and diseases because the air that exits the system has an increased velocity making the entrance of pests and pathogens much harder. Most commercial greenhouses have positive pressure system that utilizes filtered and sterilized air. The same should be employed for commercial hemp production. In commercial hemp production, if there is an issue with overall production numbers and yields, one should look at the air quality and overall air flow within a greenhouse. Design considerations should be employed to create the most effective and efficient air flow system to create a stable growing environment for plants. 

Overall air flow within a greenhouse is very important and should have a breeze that's roughly one and a half miles per hour or 132 feet per minute.  When growers first set up their growing area, the overall needed equipment or size of the equipment required to achieve this proper airflow is underestimated. an even distribution of all incoming air is preferred and in order to ensure this, greenhouse growers should utilise inflatable ventilation ducts under grow benches that expand to cover the entire length of the greenhouse. Having this constant air flow that promotes proper CO2 dispersion and eliminates any possibility of stagnant air, humidity rises, or oxygen depletion. when designing the greenhouse is important to take into consideration in terms of overall facility airflow.

 Air filtration sterilization capabilities should also be considered in the design process, making sure all incoming fresh air coming into a greenhouse should be filtered by using a commercial high-efficiency particulate air HEPA filtration or other commercial filtration method. Having air come in through non-filtered  systems opens the door wide open for pests and pathogens to enter a grow area. By filtering and sterilizing all incoming air, the contamination risk is greatly minimized.

Issues with humidity and vapor pressure deficit control or VPD can happen when a grower underestimates their dehumidification needs in comparison to the size of their equipment.

When this happens a grower's at risk of a powdery mildew or gray mold outbreak. Consultation should be made with an AG HVAC technician for indoor situation prior to construction to state your intentions, plans, size, and requirements so that they can design an appropriate automated environmental control system for high humidity environments.

Construction
During the construction process there are a few things that should be considered before designing a production greenhouse for hemp on a commercial scale. These things are expansion plans for the future, the location of the actual operation, and overall resource availability. Commercial growers should have plans for expansion to meet current and future demands for their product. Without space to expand a grower is limited and how much they can produce and as a result the money entering their pockets. Planning ahead is a must and this can range from the overall picture, logistics, all the way to work flow and plant production. Laying out the design before build-out also allows time for reflection on overall goals and desires for the operation and how to best accomplish them. The location of a greenhouse requires proper weather and sunlight, along with many other factors that impact overall profitability of a commercial operation. Heating and cooling, proximity to the market base, supplies, and whether or not there is qualified labor to work the greenhouse or commercial grow operation. Resource availability is a huge part of construction requirements and consideration. Many locations that could be used for commercial hemp production are rejected simply because there is insufficient power supply, water availability, or overall disposal reset. A commercial grower should conduct their due diligence before expanding, moving to a new location, or purchasing land in an area for a commercial operation. 

Equipment considerations and impact to greenhouse design for hemp production
When designing a commercial Greenhouse for hemp production, a grower should take into consideration all the listed challenges above well also taking into consideration equipment to be used and overall workflow. The type of equipment used in the production of hemp What influence the overall design in order to meet local, state, and other safety regulations set forth by OSHA. Decisions on the type of equipment should be made early before starting an operation. Outdoor hemp harvesting is generally done using large machines such as combines due to the requirement of minimum modifications.  When choosing equipment for indoor hemp production, equipment is a lot smaller with different requirements compared to larger operations. In a commercial greenhouse, automation is a growers best friend. This is due to the fact that a grower should consider spacing for equipment ranging from multi-tiered benches, rolling benches, irrigation/drip irrigation systems and equipment, grow lights, pots, growing medium, and overall storage of supplies needed throughout the growing cycle or season. To ensure that a commercial greenhouse for hemp production is designed correctly, recommendations by the manufacturer, as well as, plant growth requirements should be used as a basis for any and all greenhouse design. A grower should take into consideration that no two greenhouses are the same- each having different goals and needs that need met. 

For more information:
RF Agriculture
rfagriculture.com