Sanitization of Your Vertical Farming Cultivation Facility

Part I: Equipment & Surfaces

Cultivation facilities are a paradise for molds, pathogens, microbes, fungus, and invasive insects. If you think about it, they’re in perpetual states of spring or summer, which is the perfect breeding environment for pests and disease. This is why grow room sanitization is critical to keep your cannabis grow environment clean and free of anything that may increase the chances of experiencing a problem later on down the road.

Just keep one thing in mind: no matter how good of a grower you may be, even the best of them battle pests and diseases at one point or another.
In this three-part series, we’re going to look at how to sanitize your cannabis cultivation facility. Part I, below, focuses on equipment and surfaces. Part II will cover methodology around plants and substrates. And Part III will review the sanitization of HVAC and air distribution systems. We will also cover how to properly validate that your cultivation space is sanitized and we will cover a management system to help you stay compliant with local and federal regulations.

Let’s Jump In

Keeping a regular schedule of inspecting and cleaning your cultivation facility, along with the application of preventative products, is key in mitigating problems before they get out of hand. Infestations cost you labor and capital when the quality or yields from your harvest are compromised. Taking a proactive approach will save you time, energy, and money, as well as give you consistent, high-quality, cannabis yields. If you are going to put all that effort into your operation you owe it to yourself to take the necessary precautions. So, let’s get started in covering how to prevent some common problems.

Preventative Methods

One important, preventative activity is sweeping and vacuuming the grow area of any leaves, soil, or other debris. We recommend using a Shop-Vac that includes a HEPA filter, which can help prevent the spreading of pests and diseases. Many growers do this between cycles and after major plant pruning/maintenance events. But to truly make this a preventative activity, schedule regular cleanings and inspire good habits in employees who service the rooms daily.

Disinfecting Vs. Sanitizing

After the debris has been removed, you will move on to the next step of sanitizing and disinfecting. So what does it really mean to disinfect or sanitize? These words are often used interchangeably, but they are not one and the same. Let’s start with the basic term, cleaning. According to the Center for Disease Control (CDC), cleaning removes impurities, dirt, and germs from objects or surfaces. Sanitizing reduces pathogens on any given surface down to a safe level, as set forth by public health standards. In order to properly sanitize, the solution used, has to reduce microorganisms by 99.9% within a 30-second window.

Disinfecting, on the other hand, requires a reduction of these microorganisms down by 99.999% in a five to ten-minute timespan. This is basically killing these pathogens off. The difference between 99.9% and 99.999% may seem very small, but surfaces contain millions of microorganisms. It only takes a few minutes for particles to quickly spread infection. Darrel Hicks, author of “Infection Prevention for Dummies” uses the following example to highlight the difference:

“On any given day, there are 102,465 commercial flights in the world,” he says. “If 99.9 percent of those flights arrived safely to their destination, then that means 1,025 airplanes would crash every day. At 99.999 percent, only 10 would crash every day.”

So to recap, cleaning gets rid of dirt and debris on surfaces, sanitizing lowers the number of germs (99.9%), and disinfecting basically kills them outright (99.999%).

Back to Basics: How to Sanitize & Disinfect Surfaces & Equipment

According to the CDC and the US Department of Agriculture, it is recommended that you clean first, before sanitizing or disinfecting. After, the application of special solutions, like Bio-Foam which we’ll cover later, will sanitize those surfaces. A common recipe is 1 tablespoon of liquid chlorine bleach (unscented) to 1 gallon of water. To disinfect, you can choose to use special biologically safe solutions or a household bleach solution. Ensure that the surface remains wet for several minutes to make certain that you’ve killed off all the germs.

UV Sterilization

UV sterilization is a completely chemical-free disinfection and sterilization method that uses ultraviolet light to kill microorganisms like powdery mildew,  bud mold, bacteria, fungus, and other DNA-based contamination. There are 3 types of UV. UVA, UVB, and UVC. UVC is used for sterilizing hospitals, airplanes, offices, and factories. UV Sterilization uses UV light (100 – 400 nanometers in wavelength) outside of the visible light spectrum (400 – 800 nanometers in wavelength) to disrupt and destroy DNA, leaving the contaminants unable to perform their cellular functions. There are 3 types of UV light. UVA, UVB, and UVC. UVC is used for sterilizing hospitals, airplanes, offices, and factories.

Proper dosage is crucial, as some molds require 50 times higher dosage than bacteria, with using a low dosage of UV light leaving some growers disappointed with the results. On the other hand, be careful of a high dose, as it can deplete your cannabis plants with the important elements they need to grow. This includes iron, boron, manganese, and beneficial microbes. UV sterilization can also cause your plants to undergo color change and terpene loss through oxidation. Test for any deficiencies as you go, so you can mitigate problems before they get worse and out of control.

Ozone Sanitation

Ozone sanitation has become an increasingly common method of air purification in cannabis cultivation facilities. Ozone gas occurs twice, once in the upper atmosphere, which protects life here on earth from the sun’s harmful UV rays. And a second time at ground level, which is produced by pollution and smog commonly found in urban areas. Ozone gas is capable of cleaning the air in the immediate cannabis cultivation environment. Ozone sanitation accomplishes this by emitting ozone gas that kills diseases, fungus, and odors. At high levels, ozone gas can be an effective form of sterilization.

Human safety and exposure and the importance of being able to purge Ozone out through a ventilation fan after desired saturation levels/duration are achieved. NIOSH recommended exposure limit for ozone is 0.2 ppm. Ozone levels of 5 ppm or higher are considered immediately dangerous to life or health. OSHA requires that workers not be exposed to an average concentration of more than 0.10 ppm for 8 hours.CAUTION: It is important to purge Ozone out through ventilation fans after the desired saturation levels/duration has been achieved.

The National Institute for Occupational Safety & Health (NIOSH) recommends exposure limits for ozone at 0.2 ppm. Ozone levels of 5 ppm or higher are considered immediately dangerous to life or health. The Occupational Safety & Health Administration (OSHA) requires that workers are not to be exposed to an average concentration of more than 0.10 ppm for 8 hours. While ozone can be a very effective method of air purification, there are also products that can help you sanitize the hard-to-reach areas on surfaces and equipment.

Sanitization Products for Those Hard-to-Reach Nooks & Crannies

Bio-Foamer – enables the sanitization of hard-to-reach areas and surfaces. The foam ensures full coverage by creating a visual indicator of the areas of application. It adheres to those surfaces for extended effectiveness. The foam requires low to minimize water waste, which makes it ideal for drain-less operations.
The foam is left on the surface to air dry and there is no need to rinse. Bio-Foamer enables you to cover large spaces, including floors, doors, walls, ceilings, transport carts, grow trays, racks, equipment, etc.

Bio-Fogger – this is a portable sanitization and disinfecting system that uses supercharged fog. The solution is comprised of activated peroxide. You can use Bio-Fogger on air filters, dehumidifiers, ducts, irrigation lines, lights, sensors, and above-ground tracks.

Passive Systems – these “organic” air purification systems are used to protect your crops from bacteria, powdery mildew, gray mold, and all kinds of pathogens. Multi-Cluster Ionization Technology is used to create high levels of ions (both negative and positive) through the use of a Dielectric Barrier Ionizer (DBI). This creates ions that have a longer dwell time and life than other types of systems. The result is boosted efficiency in killing all kinds of pathogens, including bacteria, mildew, and molds.


We have covered the importance of using an integrative approach to sanitizing your cannabis cultivation facilities and the tools to do so. There are many types of products to assist in accomplishing this, like ozone, UV, Bio-Foam, Bio-Fogger and passive systems like the MCI technology. Your actual grow room equipment can also play a huge role in your sanitizing efforts. You may be interested to know that products like PIPP vertical grow racks contain anti-microbial and fungal-resistant additives. While they still require vacuuming of the track grooves, PIPP vertical grow racks move along the tracks and expose the entire grow room for easy and efficient floor cleaning. Best of all, the stainless steel track inserts, carriage wheels, and marine-grade aluminum carriages are corrosion and oxidation-resistant.

Keep an eye out for Part II, coming soon, where we cover the sanitization of cannabis plants and substrate, as well as Integrative Pest Management (IPM) in the vertical cannabis farm and why it is more effective than other methods of pest control.

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Sanitizing and Cleaning the Cannabis Grow Room: Part II Plants & Substrate

In Part 1 of this series, we wrote about the importance of grow room sanitation and a regular inspection and cleaning schedule. We also covered ground on the difference between sanitizing, disinfecting, and sterilizing the grow space. In this article, we’ll cover the sanitization of plants and substrates and the ways cultivators can prevent damage and loss to their crop from bacteria, fungi, pests, and plant diseases by cleaning their grow room on a regular basis.

A Preventative Approach

There are many methods to anticipate and treat issues early in the garden. One commonly utilized strategy for keeping plants clean of pests is called Integrated Pest Management (IPM). IPM applies a combination of techniques that are environmentally sound and reduce the need for pesticides.

Preventing pest problems before they arise saves time, money, and possibly the whole crop. The common methods for prevention using IPM include:

  • Creating uninviting environmental conditions in the grow space
  • Increasing sanitization of your cannabis grow room
  • Enabling plant and soil systemic resistance
  • Designing your grow room and airflow properly
  • Use of Beneficial Insects
  • Use of approved pesticides when required

Scouting and tracking for pests are one of the best preventative methods any cultivation facility can employ to get ahead of issues. Cultivators also set up spore traps around their grow rooms that are then lab-tested to identify what molds might be present. The results help guide the operation as to what processes and treatments are needed to sanitize their grow space properly. Accurate identification of pests and pathogens is crucial to deciding the method of treatment response.


The clone room growing environment is a perfect breeding ground for molds and fungus. Clones need humidity and warm temps. In addition, when they’ve first been cut, they are under a lot of stress and can be susceptible to fungus like powdery mildew. Powdery mildew can be challenging to get rid of once it spreads. It is crucial to identify the source in the grow room immediately. If the cultivation facility takes clones from its own mother plants, that is the first place to regularly inspect for early signs. If the mother plant is infected, all clones from it will be too. In this case, starting fresh with new and clean mother plants is the best option.

If your cultivation facility gets clones from a nursery, there are certain precautions that must be followed to prevent issues from entering the cannabis grow rooms. Clones should be inspected for pest and disease issues prior to purchase from nurseries. An easy process to implement in a grow room is thorough sanitizing when bringing clones in from outside the facility. A good practice is to isolate and quarantine the new clones before introducing them to the mother or vegetative production areas. During this time, inspect and treat thoroughly for pests or plant diseases and treat them prior to transitioning.

All tools, equipment, and surfaces must be sterilized thoroughly. Plastics such as pots, trays, and domes should also be cleaned and sterilized prior to use in the clean grow room. 91% or greater Isopropyl alcohol diluted 30% with water is commonly used for tool and surface sanitation. Hydrogen dioxide, hydrogen peroxide, and peroxyacetic acid are commonly used to clean plants and/or surfaces. The frequency between sterilization is up to you. Some growers clean all tools daily while others between plants so as not to spread infection. The level of risk management is a personal decision.


Most growers separate their plants into dedicated cannabis grow rooms based on the plant cycle: mother, clone, veg and flower stages. When designing an indoor vertical grow facility, planning for dedicated, clean grow rooms helps mitigate risk factors plants face. If one room is infected or compromised, the team can fully address and sanitize the individual room without affecting the progress in the other rooms. Some growers choose to keep the mother plants in the same grow room as the veg plants to save on grow space. Most growers keep the mother plants in a designated area separate from veg plants to reduce the risk of cross-contamination (both pest and disease) between older and younger plants.


Just as preparing a sanitized environment is important to preventing crop failure, so is the resetting of your indoor grow room to a neutralized, clean environment that’s ready for its next round. After all the plants have been cut and transferred from the grow room to the drying room, clear all supplies from the area and remove any plant matter from the ground and trays. In addition, clean all surfaces of dried nutrients and plant matter which are food for pathogens and fungi.

Hydrogen peroxide and dioxide solutions as well as other chemical cleaners disinfect the surfaces without leaving any residue while keeping your grow room clean. Ensure the concentration of hydrogen dioxide is safe for handling and always follow the label as directed.

Grow Medium

With the exception of no-till living organic soil practices, the substrate should be new from the packaging and inspected for quality prior to use. Substrates such as rockwool and hydroton are considered to be sterile media in comparison to soil-less hydroponic mixes and soils which can sometimes have unwanted pests, like root aphids, that hitchhike along. In some cases where cultivators are reusing their substrate, growers are disinfecting before using again through methods such as steam sterilization.

Tools of the Trade

There are tried and true modern technologies in the commercial cultivator’s toolkit for growing cannabis and surface sanitization. Post-harvest cleaning with bio-foamers and/or bio-foggers are very effective in treating racking, trays, surfaces and floors. The bio-fogger uses microdroplets that enable you to get into impossible-to-reach nooks and crannies for a deeper level of sanitizing through improved surface contact.

It’s also beneficial to use equipment that is anti-microbial and fungal-resistant like PIPP’s Vertical Grow Racks in conjunction with their Drip-to-Drain or ABS Combination Grow Trays. The trays come with optional HDPE inserts and have a white powder coat finish that is UV-stable and anti-microbial and fungal resistant.

Sanitization Practices

Keeping your grow room clean and tidy is the easiest preventative method. Clean up and remove dead leaves, stems, substrate and water from the floor or and in the grow space. Pests and diseases are looking for homes, so limiting their options is an easy preventative measure. Any plant material that is trimmed off plants must be removed from the grow room after completion of tasks. Green waste and trash should be stored outside the grow room to further ensure a clean growing environment. Tools should be kept off the floor on a workbench or wall. Keep a sanitizing solution of isopropyl alcohol nearby and instruct employees to sterilize the tools before and after use.

In this Part 2 of the Sanitization series, we’ve covered Integrative Pest Management and grow room cleaning best practices for plants and substrates. We’re now ready for the last part of this series. In part 3, we’ll be talking about the sanitization of air and HVAC systems.

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