MarijuanaGrowGuide - Growing Marijuana Guide - Lighting
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In lieu of the sun, we need some electric lighting fore our cannabis plants!
Marijuana plants grow best in Latin America near the equator where the intense sun can give the plants enough energy to easily grow ten to fifteen feet tall. As the seasons change and the plant progresses through its life cycle, changes in the color spectrum of the sun and the length of the day let the plant know when it's time to reproduce.
Flowers are the sexual organs of plants. When the season changes from Spring to Fall, the plants prepare for reproduction. Since we will be removing the males, when this occurs, the females' buds will continue to grow and their THC content will continue to increase. You will need to use two different types of light for growing marijuana. This page describes the amount and kinds of light you will need.
During the stage of rapid vegetative growth, the plant will need a lot of blue-spectrum light turned on for most of the day. These lights are typically sold as daylight light bulbs. The color quality of lights is often measured on the package as color temperatue, expressed in Kelvin. The color temperature you want for this stage of growth will be higher, in the range of 6,500K. For good vegetative growth, you will need at least 2,000 lumens per square foot.
There are several types of lights that work well in this color range. If your budget is not particularly tight, you can purchase some Metal-Halide or MH lights. These lights are ideal for the vegetative growth phase of the growing process. They can produce significant qantities of light. MH lights require ballasts in order to operate, and tend to be more expensive. They also produce more heat. For a small grow operation, MH lights might actually be overkill. I would recommend fluorescents.
There are two types of fluorescent lights that are usable for growing marijuana. There are grow-light fluorescent tubes. A popular brand of fluorescent grow-light tubes is Grow-Lux, but several other brands exist. These kinds of lights require fluorescent fixtures to be used, which are available at any hardware story for only $5-$10 and they are relatively easy to construct.
The other type of fluorescent lights that can be used are known as CFL's. CFL's or compact fluorescent lights screw into standard bulb sockets and have a higher output of light. They can also be purchased in multiple spectrum ranges. For the vegetative phase, you want to use Daylight bulbs with a color temperature of 6,500K. When lit, they appear a clean white, almost blue color. CFL's are the choice for lighting in small grow operations. They emit very little heat and can be used with reflectorized clamp sockets available at Walmart for as little as $5.00.
For the flowering stage of growth, the plant will grow best with a high proportion of red-spectrum light (approximately 2,700K) turned on for only about half the day. The actual quantity of light should also be increased as well to at least 3,000 lumens per square foot. There are no fluorescent tubes available which offer good light in this specture. CFL's can however reach this spectrum and are sold as soft white lights. They appear orangish-yellowish when lit.
A brighter light that operates well in this spectrum is High-pressure Sodium light, or HPS. HPS lights require a ballast system to operate. HPS lights emit a lot of heat, so they should be placed farther away from the plants than the fluorescents.
All this lighting stuff can be confusing, so the following list summarizes the pros and cons of the various lighting types.
- Metal-Halide: High intensity light that produces a lot of blue-spectrum light. Requires a ballast to be operated. Great for the vegetative phase.
- Fluorescent Grow-light Tube: Long tubes that produce blue-spectrum light. Requires fluorescent fixtures to be operated. Great for the vegetative phase.
- Compact Fluorescent Light: Small spiral shaped tubes that produce either blue or red spectrum light. Fit standard light sockets. Great for vegetative phase (daylight/6,500K) or flowering phase (soft white/2,700K).
- High Pressure Sodium: High intensity light that produces a lot of red-spectrum light. Requires a ballast. Great for the flowering phase.
In reality, the sun never fully converts from one spectrum to the other. It can actually be beneficial to use both blue and red spectrum lights at all times. Instead of switching light sources entirely, choose a ratio of about 3:1 for either phase. That is, for the vegetative phase, use three times as much blue spectrum light as red spectrum light and for the flowering phase use three times as much red spectrum light.
You will also need a timer for your lights. Timers are sold at any hardware store or Walmart for around $5. They can be programmed to have different on/off periods, which will simulate day/night periods. For the vegetative phase, you want to have longer day periods, usually 18 hours on, 6 hours off. For the flowering phase, shorter days signal the coming of fall, usually 12 hours on 12 hours off. Invest in a timer, because turning the lights on and off becomes a pain and forgetting can mean the difference between good and bad marijuana production.
Don't worry if this seems a little intimidating. We will remind you of what kinds of lights to use when we start growing. For a small grow operation, I recommend using CFL's the entire way through. They are readily available, have a high light output, and can be purchased in spectrums ideal for either growing phase. Now that you have most of your supplies, you need to build your grow room.