Tag Archives: mitigation

Protect Your Business: Comprehensive Rodent Exclusion

By David Colbert
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Many experts agree that of all pests threatening the cannabis industry, rodents are the most dangerous. Not only do they chew on cannabis plants and ruin crops at an incredible rate, they also contaminate product with their urine and feces. Rodents post a serious threat to cannabis facilities at every level of the supply chain.

Rodents’ incisor teeth never stop growing; left untouched, a rat’s incisor teeth would grow 4 inches in a year*. For this reason, they must constantly gnaw on things around them to wear them down. Unfortunately for cannabis growers, the woody stalks of cannabis plants present a perfect target. The destructive power of rodents cannot be overstated – creatures that can gnaw through plastic, wood, aluminum, brick, cement and even lead will make very short work of cannabis crops.

The notion that growing cannabis indoors will protect it from rodents is a misconception. Their destructive gnawing power makes rodents highly adept at getting inside buildings. Rodents can enter a building through an opening as small as 1/4 inch, and they will use any means necessary to reach the food and shelter that a heated building provides. In addition to squeezing through minuscule openings, rats and mice can climb wires and rough surfaces, jump considerable distances and tread water for several days.

Rodents, easily squeezing through small openings in a facility, will find food and shelter that a heated building provides

And once they are inside, it is already too late. Pest control experts worldwide agree that exclusion – the technical term for using physical barriers to prevent rodents from entering a building vs. trying to remove them once inside – is the safest, most effective approach to rodent control. This is because once rodents have gained entry, they will contaminate – and multiply – at an alarming rate.

In one year, two mice could potentially multiply into more than 5,000 mice and two rats could become 1,250. In that same year, a single rat can shed more than half a million body hairs, and a mouse can produce up to 18,000 fecal droppings. Rodents eat or contaminate at least twenty percent of the world’s food supply each year (according to the Indiana Department of Health) and carry diseases including rat bite fever, hantavirus, leptospirosis, salmonellosis, murine typhus, and even the bubonic plague. According to experts from Total Food Service, “Mice are known to frequently carry salmonella bacteria in their digestive tract, so salmonella can be easily spread through contact with rodent waste. This is true with marijuana [sic]edibles just as it is with other food products.”

Keeping rodents out of cannabis facilities is fundamental to protecting crops and products. The most common rodent entryways include exterior doors, open garage and loading dock doors, windows, air vents, fireplaces and at points where electrical, water, gas, sewer and HVAC lines enter the building. Rats and mice can also gain entry through tiny cracks in the foundation, by gnawing through the standard rubber and vinyl seals on most garage and loading dock doors, and beneath roofing tiles.

Consider the following exclusion best practices highlighted in The Mallis Handbook of Pest Control:

  • Safeguard your doors. Wooden doors are continuously vulnerable to the gnawing of rats. Sheet iron flashing should be installed surrounding the door, and any clearance below the door must be smaller than 3/8 inch. All doors should remain closed when not in use and be fitted with proven, specialized rodent-proof door sweeps.
  • Ventilator grills and windows should be protected with proper and proven exclusion materials, ensuring any voids or cracks are filled.
  • Defective drain pipes provide a transportation pipeline for rodents. A perforated metal cover should be cemented over the drain pipe, and any small openings surrounding the drain where it enters the building should be patched or filled with proven exclusion material.
  • Large sidewalk cracks should be sealed as these crevices allow rodents to access a building’s foundation, enabling them to more easily search for entry points. Foundation walls can be protected with barriers of metal, concrete, or brick around and below the foundation.
  • Circular rat guards should be placed around all vertical wires and pipes.
  • Ensure that cracked or broken roofing tiles are identified and replaced in a timely manner, and utilize proven exclusion material to fill any voids.

It’s also critical that only proven, rodent-proof exclusion materials be utilized to seal entry points. Caulk, mortar and spray foam offer almost zero protection against the gnawing power of rodents. Steel wool is often used for filling cracks and crevices, but will eventually rust and break down, rendering it useless against rodents. All exclusion materials should be made of stainless steel or other permanent elements.

Rodents are not easily deterred, but a well planned exclusion program can save you from costly infestations

Standard rubber door sweeps used for weatherization are not designed to withstand rodent gnawing, making the small gap beneath and around exterior doors a primary rodent entry point. Specialized rodent-proof door sweeps are fundamental to effective rodent exclusion. Xcluder’s Rodent-Proof Door Sweeps feature a core of Xcluder Fill Fabric – a blend of stainless steel and poly-fiber with sharp, coarse fibers that rodents cannot gnaw through – reinforced gaskets for a superior weatherseal and an extended rubber flap to create a flush ground seal against insects and other outdoor contaminants. Installing rodent-proof door sweeps is arguably the single most important step in protecting cannabis facilities from rodent infestation.

Sanitation is also important. Food products of any kind must be stored in sealed containers. Garbage should be collected frequently and stored as far away from the building as possible. Clutter should be avoided in storage areas as crowded shelves and boxes create opportunities for rodent nesting. Roofs and gutters should be free of debris as standing water attracts rodents as well. All trees and landscaping should be trimmed back away from the building to prevent not only rodent burrowing but also access to the roof.

Rodents are not easily deterred, but a well-supported, thorough exclusion plan is the strongest weapon in the fight against rodents. Investing the time and resources to properly safeguard buildings against rodents before a problem is identified is the best way to protect the plants, products and personnel inside cannabis facilities.

photo of outdoor grow operation

How to Reduce Mold & Contaminants in Indoor, Greenhouse and Outdoor Grows

By Ketch DeGabrielle
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photo of outdoor grow operation

Controlling your grow environment doesn’t start when you germinate your first seeds, it starts before you build your grow. There are steps you can take that will have a significant impact on mold growth and contamination, and these will vary based on the grow environment you choose.

Below is a roadmap to where each grow environment stands in terms of mold and contamination risk, and simple steps you can take to mitigate these factors.

Outdoor

The benefits of an outdoor grow are significant – using natural sunlight to grow plants is both inexpensive and environmentally sound. However, it allows the least amount of control and makes plants susceptible to weather conditions and outdoor contaminants including dust, wind, rain and insects. Depending on humidity and precipitation levels, mold can be a big issue as well.

Outdoor growing has obvious benefits, such as natural sunlight, but may also require extra steps to prevent contamination

When selecting an outdoor area for a cannabis farm, there are two important factors to consider: location and neighboring farmland. Geographical environments and sub-climates vary and once you have purchased land, you are committed, so be sure to consider these factors prior to purchase.

While arid desert climates have abundant sunlight and long growing seasons, flat, dry lands are subject to dust-storms, flash floods and exceedingly high winds that can damage crops. Conversely, more protected areas often have high humidity and rainfall late in the season, which can create huge issues with bud rot and mold. Neighboring farms also have an impact on your grow, so be sure to find out what they cultivate, what they spray, their harvest schedule and how they run their operation. Large farming equipment kicks up a lot of contaminant-laden dust and can damage crops by displacing insects to your farm if they harvest before you. Pesticide drift is also a major issue as even tiny amounts from a neighbor’s farm can cause your crops to fail testing, depending on what state you are in.

With outdoor grow environments always at the mercy of Mother Nature, any cultivator is wise to control contamination potential on the ground. Cover soil and protect your crop by planting cover crops and laying plastic mulch on as much ground as reasonable. In many cases it makes sense to irrigate uncultivated parts of your farm just to keep dust down.

Greenhouse

Greenhouses are the future of cannabis cultivation. They allow growers to capture the full spectrum and power of the sun while lessening environmental impact and operating expenses, while still being able to precisely control the environment to grow great cannabis. With recent advancements in greenhouse technology such as automated control systems, positive pressure, geothermal heating or cooling and LED supplemental lighting, greenhouses are the future. However, older or economy greenhouses that take in unfiltered air from outside still have a medium amount of mold and contamination risk.

A greenhouse grow facility

Before building your greenhouse, study the area while taking into account climate, weather conditions and sun exposure. Excessively windy areas can blow in contaminants, and extremely hot climates make cooling the greenhouse interior a challenging and costly endeavor.

There are several simple operational tactics to reduce contaminants in a greenhouse. Add a thrip screen to keep insects out, thoroughly clean pad walls with an oxidizing agent after each cycle, and keep plants at least 10 feet from pad walls. Plan to flip the entire greenhouse at once so that you can clean the greenhouse top to bottom before your next crop. A continuous harvest in your greenhouse allows contaminants to jump from one plant to the next and reduces the ability to control your environment and eliminate problems at the end of a cycle. Lastly, open shade curtains slowly in the morning. This prevents temperature inversion and condensation, which can cause water drops to fall from the ceiling and transfer contaminants onto plants below.

Indoor

An indoor environment offers ultimate control to any grow operation. Cultivators can grow high-quality cannabis with the smallest potential for yeast and mold growth. Unfortunately, indoor environments are extremely expensive, inefficient and environmentally costly.

Talltrees
An indoor cannabis operation set up (Image: Tall Trees LED Company)

With indoor grow environments, keeping mold and contaminants at bay comes down to following a regimented plan that keeps all grow aspects clean and in order. To keep your grow environment clean, change HVAC filters multiple times a month. It’s also important to install HEPA filters and UV lights in HVAC systems to further reduce contamination threats. Clearly mark air returns if they are near the ground and keep those areas free of clutter. They are the lungs of your grow. Also, stop using brooms in the grow space. They stir up a lot of contaminants that have settled to the floor. Instead, use HEPA filter backpack vacuums or install a central vacuum system. Set up a “dirty room” for anything messy on a separate HVAC system, and be sure to thoroughly clean pots after every harvest cycle.

Learn more about reducing mold and contaminants in an indoor or greenhouse grow in another article from our series: 10 Ways to Reduce Mold in Your Grow.