Growing high-yield medicine indoors, at home, needs a carefully-designed indoor grow tent.
There is not a single right way to grow cannabis indoors. While growers can leave a plant in a pot by the window, plants will yield a considerably higher crop with a little planning and effort on the part of the grower. An indoor grow tent can be a huge step in this direction.
Before setting up an indoor grow tent, the first thing to ensure is cleanliness and sterility. Growers should cover the walls, floor, and ceiling with poly to create a sealed environment that also serves to protect the rest of the home from moisture damage.
An Indoor Grow Tent Exhaust System
Exhausting is an important consideration with a grow tent set up. The odor from growing cannabis plants is often overpowering and will quickly fill the home and surrounding area.
It’s advisable to place the exhaust outlet high in one corner of the room opposite to an intake, ideally located low down on the other side. This helps ensure minimal stagnation and efficient air exchange throughout the grow tent.
Carbon Filters to Remove Odor
Carbon filters are generally the preferred choice for odor control of indoor grow tents. Where other solutions, like ozone generators, produce a potentially dangerous compound to bind the odor, carbon filters are safe and efficient with no unwanted side effects. In carbon filters, molecules responsible for the odor bind to the activated carbon within the filter while the remaining air passes through unobstructed.
CO2 Supplementation
Many beginning indoor growers are surprised to learn that CO2 is both necessary and desirable in an indoor grow tent. Like all plants, cannabis extracts CO2 from the atmosphere via the stomates on the leaves. It then uses the CO2, in conjunction with light, to produce the oxygen and sugar necessary for plant growth.
Indoor plants will grow much more effectively and give higher yields with optimal CO2 levels. Cannabis plants can tolerate levels of up to 1800 ppm (parts-per million) of CO2 during the lights-on period, while during the lights-off period, levels should decrease to below 500 ppm.
Without adding CO2, average environmental levels range from 400-500 ppm. A study published by the European Geographical Society (2017) [1]Verhulst, K. R., Karion, A., Kim, J., Salameh, P. K., Keeling, R. F., Newman, S., … Miller, C. E. (2017). Carbon dioxide and methane measurements from the Los Angeles Megacity Carbon Project … Continue reading measured carbon dioxide levels from the Los Angeles Megacity Carbon Project. Researchers found average annual CO2 levels to be 421 ppm. Such levels are adequate for plant growth if growers ensure that the air consistently circulates. But, for those who chase optimal growth, their cannabis plants will benefit from CO2 supplementation.
How to Add CO2 to Your Home Grow
Common methods of introducing CO2 include the use of compressed CO2 in bottles or gas regulators. In the case of the latter, an attached airline teed off at several points is tied to oscillating fans to help ensure optimal distribution.
Although plants will benefit from enhanced CO2 levels, it’s not strictly necessary. For those who decide to forgo this supplementation, it’s critical to move a considerable amount of air at a rate of approximately 150-200 CFM (cubic feet per minute) per 1000 watts of light to ensure the plants have access to sufficient CO2 levels.
Environmental Control of the Indoor Grow Tent
Stability, in both temperature and humidity, is crucial for any indoor grow tent. One essential part of any grow tent set up is the installation of a temperature and humidity gauge. During the lights-on period, the temperature should hover in the eighty to eighty-five degrees Fahrenheit range, while during lights-off, temperatures can drop to a minimum of seventy degrees Fahrenheit. For anyone with aspirations of high indoor yield, maintaining that ten to fifteen degrees Fahrenheit differential between lights-on and lights-off is essential.
A study published in Physiology and Molecular Biology of Plants (2011) [2]Chandra, S., Lata, H., Khan, I. A., & Elsohly, M. A. (2011). Temperature response of photosynthesis in different drug and fiber varieties of Cannabis sativa L. Physiology and molecular biology of … Continue reading
investigated rates of photosynthesis at different temperatures in cannabis. Researchers found temperature to be a “major environmental factor influencing the growth.” In particular, temperatures above eighty-five degrees Fahrenheit had an adverse effect on photosynthetic rates in cannabis.
Concerning humidity, a de-humidifier controlled by a dehumidistat should maintain constant humidity levels between fifty and sixty percent.
Indoor Grow Tent Cooling Solutions
One of the most significant challenges with any grow tent set up is in keeping excessive temperatures under control. The two most common solutions are chillers and an air conditioner.
A chiller incorporates a radiator with water flowing through it and a fan that draws in air for cooling. The effectiveness of a chiller depends very much on the temperature of the water held within. Top models automatically adjust the internal water temperature based on the ambient grow room temperature.
Air conditioners are highly effective, but come with the associated burden of high power consumption. Additionally, many high-capacity units require a three-phase power source.
A further solution involves what is known as air-cooled lighting. It involves encasing bulbs within a sealed reflector and venting them to remove excessive heat. While it provides a cost-efficient way to keep the temperature down, it can also lead to excessive condensation in the winter months due to the cold air drawn from outside. To combat this, many growers coil some ducting at the inlet enabling the air to warm up before slowly entering the indoor grow tent.
Light and Reflectors
Where HPS (High Pressure Sodium) and HID (High Intensity Discharge) lighting solutions were once dominant, LED (Light Emitting Diode) lighting solutions have become the norm in more recent years. LEDs produce a visible light spectrum of wavelengths ideally suited to plant growth. Although these have been around for over a century, recent refinements mean that these are now the most energy-efficient lighting solution on the market.
LED efficiencies above twenty percent are typical, and these produce zero heat while running. While the advantages may seem abundant, the main drawback associated with LED systems is the significant initial investment required.
Reflectors in Indoor Grow Tents
The use of reflectors can help growers make use of the available light more efficiently and hence increase yield. If using LED lights, reflectors are not required. The highly-reflective material used in the manufacturing process of LEDs serves to reflect the available light sufficiently.
For those using HID lamps, then mylar rolls will reflect up to ninety percent of the light and are an excellent option for covering the walls of an indoor grow tent. Orca grow film is also extremely reflective, and via the use of crystalline microfibres, it can reflect over ninety percent of light.
Commercially Available Indoor Grow Tent Solutions
For those who would rather avoid the DIY solution, ready-made indoor grow tents of varying sizes are widely available. Complete with instructions, grow tent setup is often quick and easy. These provide an airtight container for cannabis plants, and come complete with hangers for lights and fans. Many also come complete with a carbon filter for effective odor control and provide the all-in-one solution that many novice growers require.
References
