The primary factors that contribute to the success or failure of an indoor garden are light, grow mediums, nutrients, and air quality.
When troubleshooting an indoor cultivation operation, it is an all-too-common mistake for novice gardeners to focus on the first three elements and neglect the last.
However, finding an ideal equilibrium of air quality—mainly concerning temperature and humidity—is essential in the propagation of quality and bountiful harvests.
Indoor growers can create artificial environments inside growrooms that help alleviate concerns with airborne pathogens while ensuring efficiency with irrigation and nutrient uptake.
As the indoor gardening industry continues to evolve, it brings with it an ever-expanding assortment of technological advancements that assist in air quality maintenance.
Most notably, there are a variety of digital atmospheric controllers on the market today. These devices automatically control all variants related to air quality in an indoor garden. They accomplish this feat by electronically communicating with every piece of equipment in a growroom that dictates temperature and humidity.
Whether an indoor grower chooses to regulate the air quality in their room with less-sophisticated apparatuses, such as timers, or opts with novel environmental controls, the end game is the same: ideal growing conditions for plants.
With these notions in mind, here is a brief overview of common air quality issues seen in growrooms as well as some potential solutions.
Temperature and Humidity
The proper regulation of temperature and humidity in a growroom is the most important consideration to make in ensuring quality air for a garden.
Generally, if a garden’s temperature and humidity levels are off, the situation will render all other troubleshooting efforts regarding air flow issues and disease useless.
Maintaining ideal temperatures in a growroom can be challenging due to a variety of factors including day and night cycles within the room and outdoor temperature fluctuations. Also, different geographical locations pose different problems with temperature control in a growroom.
However, most indoor growers find excess heat to be the largest obstacle to overcome in temperature regulation. For the most part, indoor gardeners should strive for a temperature range of 75-80˚F with the lights on (day).
Growers should strive to avoid extreme temperature drops when the lights turn off (night) as this instability can retard growth and cause issues with dew point and pathogens.
Depending on the locale of an indoor garden, most air-quality issues come about as an excess of humidity. Moreover, if one is running a hydroponic system, the presence of standing water in tables and reservoirs greatly increases the relative humidity in a room.
There are a variety of reasons as to why cultivators must maintain proper humidity levels in their growrooms. For the most part, properly balanced humidity in a garden helps plants combat airborne pathogens and ensures appropriate nutrient uptake.
To illustrate, both powdery mildew and botrytis thrive in poorly ventilated, humid conditions. Also, if immersed in overly humid conditions, plants tend to pull water directly from the air instead of through their root systems.
This phenomenon can cause issues with both overwatering and malnutrition. Air quality issues relating to excess humidity can be rectified with proper ventilation and air exchange as well as with dehumidifiers.
Macro and Micro Air Exchange
Macro air exchange involves the consistent control of ambient air quality in a growroom throughout a crop’s lifecycle. To this end, expert gardeners recommend that the air in a growroom should be entirely exchanged every one to three minutes for optimum growth and vigor.
There are a couple different equipment options available that can be utilized to ensure efficient air exchange in a room: intake/outtake systems and air conditioning (AC). When properly used, these tools can help ensure proper balances of both temperature and humidity.
The use of an intake/outtake air-exchange in an indoor grow is the most traditional, and affordable, method for maintaining an optimal equilibrium of air quality in a growroom.
Essentially, these rooms are equipped with large inline fans that pull humid, hot air out of the room through ducting and pull fresh air into the room. If properly balanced, and depending on the season and geography in question, this system should rectify most issues with heat and humidity.
The use of mini-split and industrial AC units in regulating air quality issues is on the rise within the indoor gardening community, due primarily to an upsurge in sealed room growing.
With the sealed room methodology, it is essentially up to the AC unit to pull humidity from the air and regulate temperature. However, these growrooms necessitate the use of a CO2 injection system to supplement the CO2-rich air that is brought in with the traditional intake system.
Finally, micro airflow refers to the movement of air within a growroom that functions independent of the macro air exchange system in place. Generally speaking, micro airflow in a growroom is regulated by way of wall fans.
These fans ensure that air from intakes, AC systems, and CO2 devices is evenly distributed around the growroom. Moreover, they resolve issues with “dead air” pockets within indoor gardens. Dead air pockets leave portions of a garden’s canopy susceptible to pathogens due to lack of air circulation.
Controlling air quality in a growroom is a carefully balanced affair. It requires a harmonious balance of equipment, infrastructure, and troubleshooting. Most importantly, these components must work in unison to address temperature and humidity levels in a garden.
Once these core elements are addressed, cultivators can comfortably move forward alleviating less-pressing concerns with dead air pockets, CO2, etc. In the end, proper air quality will allow plants to utilize nutrients and light more efficiently, adding overall value to an indoor grow.