Another consideration with cost is that some lights run hotter than others—HIDs, for example—so they may require additional fans or an AC unit to cool down a grow space. Extra equipment means more electricity, also driving up your utility bill.
Other considerations when choosing a cannabis grow light
The typical homegrower will only need one or two lights. Most states limit grow amounts to 6 or 12 plants, and one or two lights should be plenty for that. If you plan on running two separate rooms, one for vegetative plants and one for flowering plants, you’ll need two lights.
Young and mature plants, or vegetative and flowering plants, respectively, like different types of light, and you can buy grow lights that target each spectrum. Commonly, growers using HIDs will use MH bulbs for vegetative plants and HPS bulbs for flowering. Some LEDs are also designed to target different light spectra.
LED grow lights need to be used properly to get the results, but if you know what to expect they pay you back with built-in cooling that allows a grower to hang their lights directly over their plants without worrying about fans, ducting or ballasts. They are easy on the electricity bill and don’t cause a lot of heat problems.
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 whether LEDs are a good fit for you, and you can also read more deeply into the differences between LED and HPS here.
LEDs are plug-and-play which means you can plug them directly into a wall without a ballast
How Far to Keep from Plants: 24-38″ is the standard starting distance for the vegetative stage. You can move it to 18-20″ away in the flowering stage, or possibly even a few inches closer for light-loving strains.
LEDs vs Other Popular Cannabis Grow Lights
Since growers are getting such great results with these lights, and they come at surprisingly reasonable prices for LED grow lights, I knew I needed to highlight this company as our most recommended LED grow light!
In addition to discolored leaves, too much light can also “bleach” the tops of buds
Grow Space: 2.5×2.5’ coverage at 24” (suitable for vegetative stage) and 2×2’ coverage at 18” (suitable for flowering stage)
3 Main Types of LED Grow Lights
This cola was produced under a ViparSpectra PAR600 LED grow light
October 31, 2020 – LED grow light technology has been improving rapidly especially in the last 1-2 years. Although just about any LED grow light (even the worst ones) can grow good weed, some newer models developed specifically for cannabis are getting better yields, density, and plant growth rates than older and generic models. We are currently doing extensive testing between different LED grow lights to determine which are the “best”. Every grow light on this page gets great results (just look at the pictures to see what to expect) but I’d like to specifically point out certain LEDs where the newest models are beating expectations.
There is a big misconception in the industry stemming from the LED suppliers that the ability to have your LED lights so much closer to your crop will help increase production lower into the crop. This could not be further from the truth! When your light source is closer to the top of the canopy than the shadows created from the top layer of leaves are much bigger than if the light was further away. (Use a flashlight and make a shadow on a wall with your hand. Watch how the shadow grows as you get the light closer to your hand). Also, light penetration into the crop comes from the crossover between fixtures.
When it comes to building an ROI comparing LED versus HPS be careful with results that are supplied by manufacturers of only one type of light source. I have seen manufacturers on both sides of the argument manipulate numbers to favor their specific light source. Below is an outline of things to look out for when receiving an ROI comparing lighting technologies:
This is congruent with other findings that some added blue in flower will cause this. But the reason we see these amounts vary is because every strain reacts differently to different spectrums. Keep in mind that the cannabis plant grew in nature all over the world at different longitudes with different spectrums. With all of the variations of cannabis strains in today’s market made from these ancestral plants from all over the world, each will perform differently under different spectrums.
It was only after companies like P.L. Light and Philips* introduced LED fixtures specifically engineered for truss mounting in a greenhouse, that growers really adopted this technology. These products enabled even the indoor grower to maintain some distance between the LED fixtures and the plant canopy, and resulted in production similar to growing under HPS. (*In the United States, Philips has taken the stance that they will not support sales into the cannabis industry as it is not recognized to be legal by the federal government)
The best advice I have is to get a comparison of your ROI done by a versatile company. One that can offer both technologies where you can have light plans designed to the same levels with both technologies. Don’t trust just what the LED guy says or the only HPS guy says. Look at both, do your own math. Know what works for the strains you are growing and measure your own ROI. The easiest way to do this is going to this link and ask your local PL Light Territory Manager for advice as we are the “Lighting Knowledge Company” and whether you decide to use LED or HPS, you will get a true and honest comparison of both technologies.
“What lighting source should I use for my licensed cannabis grow?”; “I am comparing LED to HPS for my cannabis operation. Which source do you recommend?” These are questions people ask me almost on a daily basis. We have covered this question in past posts on our blog, like this one by our very own head of marketing: LEDs vs Traditional Lighting but most cannabis growers know that this crop is different than most and many growers have experimented with lighting technologies on a small scale to find they can sometimes increase terpenes and THC levels just by changing their light sources. To begin, let’s unpack the information that exists on this complex topic.
With all of these factors above, how do we answer our initial questions?? Quite frankly, there is no simple answer! Every grow is different – from different: strains being grown, growing climates by geography, style of growers, indoor versus greenhouse, etc. All of these factors will weigh heavy on what is better for you!
Do this math with your LEDs as well. The PL Light TopLED is 320 watts so the BTUs will be 1092 BTUs. While that looks like a big savings it will take at least two times the amount of our LEDs to get to the same light level as a 1000w HPS. On the other side of this argument is that the LED fixtures do not provide the radiant heat as HPS and your crop roots will perform better with warmth. It is proven that there is a direct correlation between heat and crop production. Plants grow slower, producing less fruit the colder they are. In northern climates many growers rely on the heat from HPS to warm their crops.
Another area you should always do your own math on is the BTU calculation for your grow room. Yes, LEDs produce less heat than HPS and this can be the deciding factor. As the cost to cool your grow room can be one of your highest production costs. Your AC load is based on the amount of BTUs produced from your fixtures. This is simple math as 1 watt equals 3.412 BTUs. No matter what 1000w HPS fixture you use the BTUs from that fixture will be 3412!