LED grow lights are fairly new to the marijuana growing world, but they have become very popular over the last few years with their ability to produce great yields while staying cool and using a reasonable amount of electricity. With a high quality LED grow light and an average-to-good grow, you can expect yields of around 0.5 to 1g/watt.
The final yield depends a lot on strain and growth skill, along with the quality of the lamp itself, but that's a good guideline for most models. For instance, a 200W LED (200W true power draw, not an "equivalent" wattage) would produce around 100-200 grams on average, or 3.5 to 7 ounces.
Today's LED models are far better for cultivating marijuana than the ones available even a few years back. Several modern lamps are full spectrum or "wideband" spectrum (instead of just red and blue light diodes, which produce a bluish purple light and are occasionally called "blurples"). Full spectrum light is easier on the eyes and adding at least some amount of green light to blurples generally leads to healthier growth. Other spectrum colors like red, far red, and infrared are important for the budding/flowering stage. LED producers have developed customized lenses to point light directly to the plants and boost penetration, resulting in greater yields for the same amount of light compared to older models. There are also various form elements, with everything from the casing to the size of the diodes differing from model to model.
There are 3 major kinds of LEDs that are most often utilized for growing marijuana. Each kind of model has its pros and cons, so there isn't yet an "ideal" LED type. Some are better for some situations than others.
1. Spread Style
Many smaller LEDs are spread out over a large space. Examples of this design include Quantum Boards, Rack and "Spider style" LED grow lights.
The name "Quantum Board LED grow light" stemmed from Horticulture Lighting Group, though the term is currently occasionally used for any LED in this design. They tend to have relatively low wattage diodes which are spread out over a large area on a board. These are becoming more popular recently, and appear to give particularly good results for the amount of wattage used.
The "spider style" LEDs are similar to Quantum Boards in that the individual diodes are spread out and have a tendency to be on the smaller side, yet they are set on a panel with "arms" like a spider rather than a solid board. One popular example is the SPYDRx line of LED lights. These typically have an extremely high price, yet cultivators that use them swear they get better results than any other kind of LED grow light.
2. Traditional Panel
The conventional panel LEDs have small to medium wattage diodes and the lamps have a tendency to be more compact. Most LED grow lights available today are in this style. They are sort of halfway between a Quantum Board and a COB Style light, with a mix of features from both.
3. COB Style
These grow lights use large COB (Chip on Board) LED "bulbs". Each COB is very bright and intense because they have multiple LED chips in a small area. COBs generate more intense light than other kinds of LEDs, and each COB utilizes a considerable amount of electricity.
Rather than having dozens of small diodes, COB style LED grow lights typically just have a handful of large COBs, each with strong lenses to direct the light down into the plant. These are quickly gaining in popularity and are known for having deep penetration into the plant canopy.
It is also typical to see LED grow lights that only have one COB per lamp. These make it easy to spread your light over a grow space, one lamp at a time. Sometimes called "AutoCOBs". Some LED grow lights have a single COB LED. Multiple units can be spread out as needed.
Each COB has its own spectrum, so you can create a tailored spectrum for your plants by merging multiple AutoCOBs together. They are very configurable if you have an abnormally shaped grow area, or want to be able to accommodate different plants of various sizes at the same time.Some COB LED grow lights can be plugged into normal light outlets.
Select LED Grow Lights If: