As with most living things, fresh air something extremely valuable. Opening up a window or installing a fan system in the room can help provide your plants with some much-needed fresh air. Of course, if it is particularly cold outside, it’s probably not a good idea to keep the window open for too long, even if it’s your only means of recycling the air.

The cold outside will stunt plant growth and make it difficult for you to help them recover.


The temperature of the grow room and the plants is also something that needs to be monitored and regulated. The average temperature for a grow room should be around 75*F. But, cannabis is remarkably adaptive and will produce buds lower or higher temperatures. If the temperature drops to extreme lows or rises to extreme highs then you could be in for a surprise when it comes to the quality of your plants. Although cannabis can survive at temperatures around 50 to 55*F, they will not produce the best, most potent bud when the time comes to flower and harvest. In general, keeping the room at about 75*F is your best bet. In reality, plants will grow slightly better at slightly higher temperatures, but it might be difficult to maintain those higher temperatures. You might also need to counteract the extra heat by watering the plants more to cool down the roots.


Too hot, curling leaves Perfect temperature Too cold, small plants


Other Environmental Factors

Sometimes, lights present a problem when it comes to temperature maintenance. Lights that produce a great deal of heat can give the room a sweltering feel and cause the plants to dry up or burn. If this is a problem, then you might want to install an air- or water-cooled system to alleviate the heat emitted from the lights. If you must, you can even install an air conditioner if it is cost-effective for your grow room. Most houses will keep average temperatures that remain around the ideal, but it’s important for you to monitor the temperature on a daily basis to ensure that your plants are being taken care of properly.


You might think of humidity as something that occurs in the Deep South or in otherwise tropical environments. But, humidity can be found virtually everywhere including your grow room. In general, about 40 to 80% relative humidity (rH) is ideal. Humidity is basically a measurement of the water in the air. This can largely be achievable through the use of fresh air as stated above. Some growers even have an rH meter at their disposal to adequately check for ideal humidity percentages. There are also expensive devices called dehumidifiers that control the levels of humidity in a certain room. But, unless you’re planning on having a rather substantial operation, you can probably just get by with a little fresh air once in a while.

Carbon Dioxide (CO2)

Another vital component that plants need to survive is CO2. For humans, CO2 isn’t that great, but plants like cannabis use CO2 as their air. It’s basically the stuff that helps them breathe. But, CO2 is also vital for spurring and maintaining photosynthesis. If your grow room lacks enough CO2 input, then it will likely become obvious. There are plenty of methods to increase CO2 in a room, but the best way to do it is with a CO2 generator. These generators will keep a steady flow of CO2 coming into the room and the plants will be able to take it in adroitly. There’s almost no way to inundate cannabis plants with CO2 unless you somehow go really overboard. For instance, if the grow room is unsafe for you to breathe, then you might need to tone it down a little. Otherwise, the amount of carbon dioxide in the room is directly proportional to how large the plant (and later the buds) will end up growing.