LED grow lights are fairly new to the marijuana growing scene, but they have become very popular over the last few years with their ability to produce excellent yields while staying cool and using a practical amount of electricity. With a high quality LED grow light and an average-to-good grow, you can expect yields of about 0.5 to 1g/watt.
The ultimate yield depends a lot on strain and grow skill, in addition to the quality of the lamp itself, but that's a good guideline for most models. For example, a 200W LED (200W true power draw, not an "equivalent" wattage) would yield about 100-200 grams on average, or 3.5 to 7 ounces.
Today's LED models are much better for cultivating marijuana than the ones available even a few years ago. Many modern lamps are full spectrum or "wideband" spectrum (rather than 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 including at least some amount of green light to blurples typically results in healthier growth. Other spectrum colors like red, far red, and infrared are important for the budding/flowering stage. LED producers have developed specialized lenses to aim light directly to the plants and increase penetration, leading to greater yields for the same amount of light compared to older models. There are also several form components, with everything from the casing to the size of the diodes differing from model to model.
3 Key Types of LED Grow Lights
There are 3 main kinds of LEDs that are most often utilized for growing marijuana. Each kind of model has its benefits and drawbacks, so there isn't yet a "best" 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 getting more popular lately, and appear to give particularly good results for the amount of wattage used.
The "spider style" LEDs are similar to Quantum Boards because the individual diodes are spread out and have a tendency to be on the smaller side, however they are set on a panel with "arms" like a spider instead of a solid board. One popular example is the SPYDRx line of LED lights. These usually have an incredibly high price, however cultivators who 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 offered today are in this design. 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 huge COB (Chip on Board) LED "bulbs". Each COB is incredibly bright and intense because they contain several LED chips in a small area. COBs produce more powerful light than other kinds of LEDs, and each COB utilizes a considerable amount of electricity.
Instead of having dozens of small diodes, COB style LED grow lights usually only have a handful of huge COBs, each with strong lenses to point the light down into the plant. These are rapidly gaining in popularity and are known for having deep penetration into the plant canopy.
It is also common to see LED grow lights that just have one COB per lamp. These make it easy to spread your light over a grow area, one lamp at a time. Occasionally known as "AutoCOBs". Some LED grow lights have a single COB LED. Several units can be spread out as needed.
Each COB has its own spectrum, so you can make a custom spectrum for your plants by combining multiple AutoCOBs with each other. They are very configurable if you have an abnormally shaped grow space, or want to be able to accommodate various plants of various sizes at the same time.Some COB LED grow lights can be connected to normal light outlets.
Select LED Grow Lights If: