LED grow lights are relatively new to the cannabis growing scene, but they have become wildly popular over the last few years with their ability to produce great yields while staying cool and using a reasonable amount of electricity.
Yields! With a quality LED grow light and an average-to-good grow, you can expect yields of about 0.5g/watt. It depends a lot on strain, and pro growers can yield even more, but that’s a good rule of thumb. As an example, a 200W LED (200W true power draw, not an “equivalent” wattage) would yield about 100 grams on average, or 3.5 ounces.
Today’s LED models are much better for growing cannabis than the ones available even half a decade ago. They have wider spectrums of light (instead of purely red and blue light) which results in greener, healthier growth and better-looking buds. Additionally, LED manufacturers have developed specialized lenses to point light directly to the plants and increase penetration, resulting in bigger yields for the same amount of light compared to older models.
Modern LED grow lights can produce impressive results. These cannabis plants were grown completely under LED grow lights from seed to harvest!
Pic by Joe “Nunyabiz” Nunya, an avid LED grower who uses ViparSpectra LEDs
LEDs are often compared to HPS grow lights and each type of grow light has pros and cons for cannabis growers. Here’s the quick summary to help you decide, but you can also read more deeply into the differences between the two here.
Choose LED grow lights if…
You want to use the most cutting-edge indoor cannabis grow lights with a customized spectrum of light
You are willing to do some research to determine the best LED grow light for your space (this article will help guide you)
You have some extra money to spend on your initial setup (some of the best LED grow lights are expensive!)
Quality (potency, smell, trichome development) is more important to you than yields/watt.
You don’t want to deal with an exhaust system or ducting, and would prefer to just hang your grow light over your cannabis plants and let the lights cool themselves
LEDs vs CFLs
LEDs get better yields for the same amount of electricity than CFLs. This is because LEDs are much more efficient (produce more light for the same amount of electricity)
Unlike CFLs, LEDs don’t need to be adjusted almost daily
LEDs give off less heat than a CFL setup with the same amount of electricity, and LEDs also come with additional cooling options like heatsinks and built-in fans, which pushes all the heat up and away from the plants, making it easier for growers to maintain comfortable temperatures.
LEDs need to be kept much further away from plants than CFLs, which means that CFLs are better suited to short grow spaces without a lot of available height. LED grow lights generally need to be kept 12-18+” away from the tops of plants, while CFLs can be kept just a few inches away.
LEDs vs MH/HPS
I’ve seen many growers choose to mix LEDs with their HPS bulbs. In fact, combining MH/HPS with a quality LED panel may be a great way to improve the quality of your harvested buds. There are lots of growers who claim that LEDs increase potency and density, as well as bring out the natural smell/taste of your strain. On the flip side, some growers believe that HPS tends to produce “prettier” buds.
If you’re most concerned with improving your yields/watt, skip the LEDs and get an HPS grow light for your flowering stage. Although LEDs are catching up and there are some really great LEDs out there that get comparable results, HPS still tends to give you bigger yields when it comes to how much electricity is being used.
LEDs can get pretty pricey, though not all brands! In fact, some great brands are actually some of the cheapest!
Several growers believe LEDs produce higher quality buds (more trichomes, higher potency, and bring out the natural taste and smell of buds). They also tend to bring out colors.
LED grow lights come with built-in cooling systems and heat sinks which vent air up and away from plants. This can make it so that you can hang the LED grow light in your tent and not necessarily need an exhaust system to control the temperature
LEDs are plug-and-play which means you can plug them directly into a wall without a ballast
What’s the difference between buds grown under LED grow lights compared to buds grown under an HPS grow light? Do the buds look/taste/smell different?
Although this is just one example, this is pretty typical of LED grow lights in that they tend to bring out colors. This Eldorado plant was bloomed under two light sources, an HPS on one side and an LED on the other. Nothing scientific, no partitions, so there was light overlap. At harvest the color difference was surprising (see below) and after curing 2 select pieces from each side of the plant, the aromas are slightly different as well.
LED grow lights are a great choice for growers who are dealing with hot HPS lights and want to change to something that’s going to run cooler. Although LED grow lights do produce heat, the smaller models might not bring up the temperature of your grow space.
Even the more powerful models of LED grow lights that produce a lot of heat still have built-in cooling systems to help prevent the heat from beaming directly down onto your plants.
How to Use LED Grow Lights for Growing Cannabis
With LED grow lights, you will generally get better results with many smaller LED panels, as opposed to a few big LED panels. For example, you will often get better results with 2 x 125W LEDs (total 250W) than you would with a single LED model that produces 250W. This is because more panels often make it easier for you to spread the light to where it’s needed.
When it comes to growing cannabis, LED models with 3W chipsets (each individual bulb is 3W) seem to get some of the best yields/watt of all LED models without a lot of worry about light-burning your plants.
With LEDs, always look at the “actual power draw” or “actual power consumption” which is the amount of electricity the LED panel actually pulls from the wall. When comparing different LED grow lights, this is the closest you get to a side-by-side comparison.
Generally, your goal with LED panels should be 50-60 watts per square foot of grow space to get the best results.
The most important thing to remember about LED grow lights….