When it comes to growing a nice, even canopy of delicious, resin-coated cannabis buds, there’s no greater component to master than the light itself. Your grow light, like the sun, is your life source in your grow room. But unlike the sun, you have complete control over your grow light, including its spectrum, cycle, and most importantly, when developing a solid canopy, its intensity.
A light’s intensity can be thought of as the magnitude of light energy per unit of area. A lack of light intensity or low light will result in plants that “stretch” or reach for more light or may cause plants to slow their growth rate. On the other hand, overly intense lighting will result in a variety of problems, including light burn and leaf curling.
While it may be tempting to hang your light nice and low, directly above your plant canopy, and really soak them with tons of good light, it’s important to remember that too much of a good thing can quickly sour your operation and that more light doesn’t always equate to higher yields.
There are a few key points to keep in mind when determining the optimal intensity of light, such as the type of light, the period of time the light will stay on, and the spacing from the top of the canopy.
Types of Lights
Traditionally, indoor growing has taken place under high-intensity discharge (HID) lamps, which include metal halide (MH) and high-pressure sodium (HPS) bulbs. Additionally, growers have relied on T5 fluorescent bulbs for young plants, such as seedlings and clones. These lights have been the industry standard for decades as they reliably produce a broad spectrum of light and can be easily automated to emulate the changing seasons by using timers and switching bulbs.
In recent years, however, a large percentage of growers have begun to transition to the use of light-emitting diode (LED) grow lights in their grow room. LEDs boast several advantages over traditional HID lights, such as their ability to house various colours of diodes in a single board.
For this reason, many LED grow lights are equipped with a switch enabling the grower to toggle between a “Veg” and “Bloom” setting. Additionally, many LED grow lights are equipped with a dimmer switch, allowing the grower to adjust the brightness of their light on the fly. However, the main advantage of LED grow lights is their ability to generate large quantities of quality light without raising the temperature of the grow room drastically.