In my experience, the majority of growers want quick solutions to the problems they are experiencing in the growroom. I find, however, it's best to not just help them solve their problems, but also help them understand why the problem occurred in the first place.
Understanding the issue you're having in the growroom is the most effective start in creating great fundamental growing habits, and I can't stress this enough when it comes to the subject of carbon dioxide in the growing environment.
So, before we talk about how to provide carbon dioxide to your plants, I want to first provide a greater understanding of its functions.
During the day, while photosynthesis is the dominant process in leaves, carbon dioxide is taken up from the air and used in the process of making sugars. At night, when photosynthesis does not occur, respiration occurs instead, which gives off carbon dioxide.
Note that plants take up much more carbon dioxide in photosynthesis than they give off in respiration. As such, it’s best to water plants when the lights turn on. There will be an increase in room temperature at this time, which is when the heavier gases (carbon dioxide is one of them) lingering near the bottom of the plants will expand and get absorbed by the plant’s leaves to continue the photosynthesis process of creating energy and storing it for growth.
To create this energy, plants use some of the food they created by photosynthesis and oxidize. Imagine rust on metal; plants use dioxide to break down salts to create more usable food in order to produce energy for performing the myriad of energy-intensive functions needed to be done by the plant.
For example, plants must also build strong fibers in order to grow tall and withstand the wind. To accomplish this they create cellulose and lignin, which are polysaccharides (complex sugars). Because this is such an energy-intensive process, plants wait until they are under the least amount of stress. In other words, plants don’t grow during the day; they put on the yield at night.
Now that you know more about carbon dioxide, let's see how you can use it to your advantage in the growroom. As a re-cap, carbon dioxide is used to help create sugars and your plants are the most hungriest when the lights are turning on.
Providing a large amount of carbon dioxide in your growroom—and keeping up levels of 1,500 ppm in both large or small rooms—takes equipment involving any combination of carbon dioxide regulators, carbon dioxide tanks, propane generators or water-cooled carbon dioxide generators.
These carbon dioxide solutions take some skill and know-how to set up initially. However, they might also provide a user with more peace of mind that their plants are getting steady levels of what they want, when they want it.
Alternatively, providing additional carbohydrates (sugars) at the most optimum time of environmental temperature changes, which leads to optimum carbon dioxide delivery, is (in my experience) one of the most inexpensive ways of obtaining yields similar to if you were enriching the environment with carbon dioxide.
There are many possibilities when it comes to getting more of this essential growing element using large equipment, mid-sized materials, natural methods or a combination of the three. If you’re ever in doubt, check in with an indoor gardening retail store clerk for the best solution to meet your needs and try a few things to see what works best for you and your available time and budget.