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Growing in Winter

Winter can be a difficult season to get through for everyone here in Canada, and your cannabis plants are no exception. With shorter winter days comes dry, winter air; these factors can affect your plant’s overall health. To combat these issues, we’ve got some valuable tips you can use to help your plants thrive inside throughout the winter months, leaving you plenty of time to search for that missing mitten, or wrestle with your boots.

Before you start looking into growing your own cannabis plants, it’s important to remember that there are laws in place for growing cannabis for both recreational and medical purposes. Recreational users can grow up to four cannabis plants per residence. This cannabis cannot be sold, but up to 30 grams can be gifted to consenting adults who are of legal age. As a medical patient, once you receive a registration certificate from Health Canada, you can begin growing cannabis plants within the guidelines detailed on your registration certificate. Cannabis that is grown for medical purposes cannot be sold or gifted to anyone.

Now that we have that out of the way, let’s get back to your plants. Like most plants, cannabis requires the correct mix of light, temperature, moisture, and ventilation to survive the winter months. Each one of these factors can affect your cannabis plants in different ways, impacting things like plant health, yield, and grow time.


Let’s take a quick trip back to seventh grade science class. Light is required for plants to go through photosynthesis, or in other words, to convert light energy into chemical energy. In the winter months, daylight hours are reduced and the intensity of the sunlight is diminished. This can cause your plants to show reduced growth throughout the winter.

Most people growing their own cannabis plants will use HID (high-intensity discharge) lighting over the winter months to ensure their supply remains steady. These can also be used year-round to ensure consistency, and in some cases, can produce an increased yield.


During the day, your plants should be exposed to an environment between 24º and 30ºC, and between 18º and 22ºC overnight. If the temperature dips below 16ºC, the quality and growth will likely be negatively impacted.

If you are using HID lighting (as mentioned above), keep in mind that they can emit heat, which can affect the temperature of your plant’s environment. As temperatures naturally drop in the evening hours, it can be helpful to increase temperatures overnight. If you don’t already have one, a programmable thermostat can help you monitor your plants’ environment and, as a bonus, can even help you save money on your monthly energy costs when programmed correctly.


Now, back to science class. Moisture in the air is most commonly known as humidity. The amount of humidity in the air is directly tied to the temperature; as the temperature fluctuates, so does the amount of moisture in the air. The warmer the air, the more moisture it can hold.

In winter months, it’s harder to maintain a consistent temperature, and therefore, maintain consistent moisture levels. As the temperature and humidity fluctuate, there is an increased risk for condensation on or around your plants. Wet, or even damp, conditions can create the ideal breeding ground for mold and mildew.

If your home is dry in the winter, it may be beneficial to purchase a humidifier. This can be utilized to add moisture to the air and many of them can be set to maintain a certain percentage of humidity. On the flip side, if you find that you have moisture build up on or near your plants, adding a dehumidifier to the mix could be what you need. This will actively draw moisture out of the air, helping to maintain the ideal level for your plant’s environment.

It’s clear to see that things like lighting, temperature, moisture, and ventilation are all interconnected. There is some added responsibility to maintaining your plants’ health throughout the winter months, but with some close attention, and some minor tweaks, you should be able to maintain healthy cannabis plants. Above all, remember to monitor your plants closely throughout the winter and be sure to adjust their environment as needed.

Happy Growing!

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