Growing Cannabis In A Cold Climate Greenhouse: 4 Steps To Boosting Production

Across northern climates, winter can be the bane of any cannabis grower’s existence. The change in season brings cold temperatures, heavy snow and severe wind loads, which can create a number of hoops for ill-prepared operations to jump through.

With all of the challenges cannabis growers already face in the industry today, it’s important they use every tool at their disposal to keep bud quality consistent year-round. For cold climate greenhouse growers, this means building a structure that is reliable, well-insulated and energy-efficient to try and level the playing field with operations in warmer locations.

In general, there are four key steps growers should take to accomplish this feat, so they can harvest top-shelf product 365 days a year and maximize their bottom line. By making improvements to their greenhouse’s insulation, optimizing their heating system, implementing humidity control and employing a dependable, engineered structural design, operations can maintain an ideal growing environment that helps boost profitability, no matter how extreme the weather gets.


The first step to creating a growing environment where cannabis can thrive during the winter months is successful heat retention. Thermal resistance, or a structure’s ability to resist heat loss and prevent temperature fluctuations, is largely impacted by insulation.

There are several measures growers can take to bolster insulation in their cold climate greenhouse, starting with the structure’s cladding. Cladding plays a major role in a greenhouse’s ability to retain heat, making it vital for growers to use material with a high R-value.

One of the most thermal resistant materials available to cold climate greenhouse growers is twin-wall polycarbonate. With an R-value of 1.72 in 8 mm thickness, this cladding does an excellent job of maintaining interior temperatures, while also providing cannabis plants with valuable light transmission and UV protection.

Inside a hybrid cold climate greenhouse

For operations that deal with particularly cold winters, it can also be a good idea to clad the sides of a cold climate greenhouse with insulated metal panels. Combined with a twin-wall polycarbonate roof, growers can use these panels to create an energy-efficient, thermal-resistant structure that’s ideal for cannabis production. Insulated metal panels can even assist with light deprivation, which greenhouse growers depend on to control cannabis growth stages.

If growers want to complement their cladding with an additional thermal barrier, they can install heat retention curtains on their structure. These curtains help prevent heat loss during cold nights, allowing growers to run their heaters less and save on energy costs.

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After addressing the structure itself, cannabis growers can then focus on optimizing their heating system. The right heater is vital to creating a consistent year-round growing environment in any cold climate greenhouse.

When planning their heating system, growers will first want to look at performance and energy-efficiency. The Modine Effinity 93 continues to be one of the top solutions on the market, providing growers with a cost-effective and reliable heat source, whether they use natural gas or propane.

Commercial cannabis growers with larger greenhouse bays should also consider acquiring multiple heaters, so they can install them at opposite ends of their structure. This will help optimize utility usage and create uniform temperatures throughout an entire growing space, leading to healthier, more robust yields.

Once installed, the best way for cannabis growers to take advantage of their heating system is by implementing a smart controller. Smart controllers are capable of reading temperature sensors automatically, turning heaters off and on when a pre-determined temperature is reached. This can help maintain optimal growing conditions in a cold climate greenhouse and extend the lifespan of a heating system.

The latest smart controllers can also assist growers with data collection, helping them gather new information every harvest that allows them to further optimize their climate control equipment. As a result, growers can make well-informed changes to their growing strategy over time, improving crop quality and limiting energy consumption.

Modine Heater and HAF fan in a cold climate greenhouse
smart controller inside a cold climate greenhouse


Humidity is always going to be a primary concern in any cannabis grow. Operations in warmer regions can generally rely on a blend of active and passive ventilation to manage humidity levels, but those in a cold climate greenhouse have to depend on other methods to keep moisture in check.

Exhaust fans are effective ventilation tools three seasons out of the year, but using them during winter will cause cold air to enter a structure and a surplus of heat to escape. Rather than running exhaust fans and creating temperature fluctuations, cannabis growers can outfit their cold climate greenhouse with either horizontal airflow (HAF) systems or vertical airflow (VAF) systems.

HAF fans circulate air across a grow space, distributing heat evenly and helping avoid stagnation, so plants sustain healthy and uniform development. VAF fans can either take air from the top of the greenhouse and send it down or pull air from the bottom and push it up.

The top section of a cold climate greenhouse, or the gable area, will generally trap more heat than other spaces inside the structure. When VAF fans pull from this location, that heat is then spread into the canopy, promoting more consistent temperatures and circulating air where it matters most.

Dehumidifiers are also vital to controlling humidity in a cold climate greenhouse. Dehumidifiers can remove a substantial amount of moisture from the air and help prevent condensation from accumulating on a structure’s cladding. If left unattended, that excess moisture can create a breeding ground for mold and mildew and cause significant damage to a harvest.

air circulation systems and light dep in a cold climate greenhouse


The last thing northern growers will want to worry about is their structure collapsing under the stress of heavy snow or wind loads. These operations will need to ensure their cold climate greenhouse is designed for their specific region, which means employing high-quality structural components and taking advantage of engineering.

By getting an engineered structure, growers can rest easy knowing their cold climate greenhouse satisfies local permits and is capable of withstanding extreme weather. Through CASTA design, GrowSpan can customize structures for just about any location, allowing them to thrive in areas that deal with severe winters, like New England or the Great Lakes region.

A cold climate greenhouse with a peak-roof design, like GrowSpan’s Series 2000 Greenhouse, can also be beneficial for winter growing. This design helps reduce the buildup of snow and ice by letting it slide off the structure and onto the ground.

Although it can be daunting, the cold season doesn’t have to impede on a cannabis operation’s success. By taking the right preventative steps, northern growers can prepare themselves for the change in weather and keep production running seamlessly through winter and into spring.

Looking for more ways to improve cannabis growth in your cold climate greenhouse? Call or REQUEST A QUOTE today and let our Greenhouse Specialists offer their assistance.


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