Dial in these 4 Climate Factors for Cannabis Success
Would you rather be hanging out at the beach in Hawaii right now? So would your Cannabis Plant! It’s probably not a great idea to get on a jet with your favorite houseplant, but you can create a paradise right at home. Read on to learn how to provide a perfect climate for your herbs to thrive.
There are several different climate factors that need to be controlled for us to provide a plant paradise.
These factors interact to create an environment that will support vigorous growth, while minimizing plant disease.
Let’s start by defining the four critical climate factors that we need to control.
1) Temperature
2) Relative Humidity
3) Air Quality
4) Air Movement
1) Temperature
Cannabis enjoys sunbathing while wearing nothing at all. As you can imagine, the perfect temperature for this activity is between 72 and 85 degrees.
It is not the air temperature that matters most, but the leaf surface temperature. This measures the radiant heat the plant is receiving and will vary depending on the light source. A laser thermometer is the perfect device to measure leaf surface temperature.
2) Relative Humidity
The Relative Humidity is the amount of moisture in the air, relative to the total amount of moisture that air can contain at that temperature. As air gets warmer, its ability to hold water increases. As air cools, its ability to hold water decreases.
Imagine sipping an ice-cold beverage on the beach. The hot air can hold a lot of water. When this hot air contacts the cold glass, it cools and loses its ability to hold the water which condenses on the cool surface.
Temperature and Relative Humidity are always related. The temperature at which water will condense on surfaces at a given humidity is called the dew point.
3) Air Quality
For plants, the sweetest air contains lots of Carbon Dioxide (C02). Plants evolved in an environment with much higher levels of C02 than current levels.
Photosynthesis requires plants to uptake C02 and exhaust oxygen and water vapor through pores on the undersides of leaves called stomata.
This process is known as transpiration and helps to pull more water and food from the root zone. If plants are kept in a confined space like a grow tent, with no air exchange, they will quickly deplete the C02 and stop growing.
4) Air Movement
Air movement is critical for pest management and plant growth. Turbulence and stagnant air are our enemies here, so you will want to organize the movement of air through your garden.
Air should flow smoothly through your canopy like an ocean breeze. This will eliminate microclimates and strengthen plant stems to support your pungent flowers.
Now that we have reviewed the basic climate requirements for plant health, let’s look at some of the ways we can optimize the climate to benefit our Cannabis crop.
Monitor your Climate
You can’t fix what you are not aware of. To understand what is happening in your grow, you need a climate data logger.
This is a simple Bluetooth device that monitors your Temperature, and Relative Humidity 24/7.
These metrics are graphed over time, and trend lines enable you to fine-tune your climate equipment.
You can also use this data to confirm your photoperiod due to the effect lighting has on the grow environment.
Exchange Air
Even super-efficient LED grow lights will generate quite a bit of heat in a confined space. Your hard-working plants will produce a ton of water vapor and will consume C02 like canapes. This will quickly result in an environment that is not conductive to plant health. Air exchange can address these issues.
Air exchange for indoor gardens usually involves an exhaust fan, fitted with a carbon filter, which negatively pressurize your grow chamber and pulls in fresh air through passive vents. This system helps to manage the smell of success and to keep the climate in range.
If the only climate management tool you are using is an exhaust fan, you should use one that enables speed control, so that you can regulate the rate of air exchange based on humidity or temperature.
Manage Humidity
During vegetative growth, Cannabis plants grow most vigorously when Relative Humidity is between 65 and 70 %. This is the sweet spot for photosynthetic efficiency.
As the flowering stage progresses Cannabis plants begin to senesce, signaling the end of the plant’s life cycle. At this stage, Cannabis plants are very susceptible to fungal pathogens, and it is recommended to keep RH below 60%
Mature cannabis plants transpire lots of water. In some cases, adequate dehumidification can be achieved by heating, cooling, or exchanging air. In other cases, mechanical dehumidification will be required to provide an acceptable environment for your plants.
Humidification can also benefit your garden. When Relative Humidity falls below 50% your plants will be forced to close stoma to limit water loss, thereby decreasing photosynthetic efficiency. Evaporative humidifiers can contribute to plant health and will also have a cooling affect.
Get Zen with Airflow
Organize air movement through your grow chamber with directed air circulation. Air should enter your chamber and mix efficiently before exit. Oscillating fans create turbulence and should be avoided. A smooth vortex of air circulating within your grow chamber will eliminate microclimates and optimize photosynthetic efficiency.
Seal it up
For larger grow rooms, it is often beneficial to avoid air exchange during the photoperiod, run an air conditioner, and supplement with C02.
This enables all climate factors to be controlled more precisely and your plants will benefit from CO2 enrichment. If you are growing in a tent, control air exchange, and don’t worry about C02.
You will get the best results from your plants by understanding their climate requirements. Plants are not particularly adventurous, in fact, they hate change. It is important to minimize climate fluctuations, and transition plants gradually through the various growth phases.
