cannabis under led lights
Could LED lights be the future of indoor cannabis growing?

How can you get the best possible yields from your cannabis crop, using LED grow lights?

LED lighting technology is finally becoming mainstream. It's been well over a decade since LED grow lights first became commercially available, and it's taken the industry some time to accept and start taking advantage of them.

In the early years, LED lights were unpopular among growers as they were deemed too expensive and not powerful enough to yield a good harvest.

Although it's true that earlier models were generally not as powerful or efficient as newer models available today, it's also true that LEDs do require a modified approach to what's required for high-pressure sodium (HPS) lights, the industry standard.

So even today, with some of the most powerful grow lights available, some growers are not getting the results they could get if they optimized their approach. Thus, the industry still clings on to a lingering belief that LEDs are "no good for flower", and that it's basically impossible to get good yields.

However, it's absolutely possible to achieve high yields, and the overall quality of the harvest can be exceptionally high.

LEDs – the Pros & Cons

There are various advantages to using LEDs, but there are also some potential downsides – although these can generally be overcome with the right approach.

Let’s take a look at the pros & cons of working with LED lights.


The Pros of LED lighting


Low energy consumption

Without doubt, the huge reductions in energy are the most attractive aspect of LED lighting systems.

With modern, efficient systems, comparable yields can be achieved using a little over half the energy of HPS lights.

Finely-tuned spectrum

close shot of cannabis plant
With LED lighting, manufacturers can customize the lighting spectrum to fit the exact needs of the plant.

LED lighting systems are made of hundreds of individual LED chips that each emit light in a narrow bandwidth of the visible light spectrum.

By putting together lots of chips with different bandwidths, manufacturers can create a finely-tuned spectrum that delivers light in the exact wavelengths most needed by the plant.

Some systems can even be fine-tuned for precise spectra for cloning, vegetative or flowering growth.

Cool running temperatures

Another great advantage of LEDs is their far cooler running temperature compared to HPS.

Particularly in summer, indoor grow room temperatures can be become extremely hot when using HPS lights, necessitating powerful cooling systems.

LEDs offer a chance to keep temps under control with far less energy expenditure!


The Cons of LED lighting


High startup costs

Good-quality LED lights are very expensive – that’s inarguable. But given the energy savings, that startup cost can quickly pay for itself.

Risk of light bleaching

This phenomenon also happens with intense HPS lights, but can be more common with LEDS.

The coolness factor may help to make growers think that it’s ok to have the plants very close to the light (and with early, weak LEDs, you had to have them very close).

But it’s actually very important to keep them at the correct distance so that they don’t receive an overwhelming amount of light!

Heaters may be required!

Particularly in winter, your grow room may end up being too cold, whereas HPS lights would keep it warm and toasty.

With LEDs, you may need to use heaters so your plants don’t suffer – and at that point, it becomes a question of which approach is more energy-efficient. HPS lights and no heaters, or LEDs plus heaters?

How Many Grams Per Watt Can You Produce With LEDs?

growing cannabis plants under led lights
The big question: Are LED lights worth the money?

This is one thing many interested growers want to know before they make the switch.

By conventional standards, if you yield a harvest of one gram of dried cannabis for every watt of light produced by your fixture, you're doing well.

In fact, with all but the highest-yielding varieties, harvesting more than one gram per watt is quite an achievement!

But with LEDs, all that goes out of the window.

Look at it this way – if you spend $1,200 or more on a top-end, 350W LED light, and it produces one gram per watt, you'll only produce 350 grams of weed.

That would be pretty disappointing, and you'd wonder why you ever switched from HPS lighting!

So, LEDs SHOULD produce more than one gram per watt, if they are to be of any use in the industry.

In fact, producing 1.5 - 2 grams per watt seems to be quite standard these days in the LED growing community, and some people claim to achieve as much as 3g/W.

Modern LED fixtures can achieve these high yields as they represent a much more efficient way to create light compared to HPS lights, which waste a lot of electrical energy in the form of heat.

Choosing the Right LEDs

led lights
With so many options, a little guidance is helpful to make sure you choose the right lights.

To ensure all-around good quality and decent yields, the first step is to choose a reputable LED manufacturer.

Today, the top manufacturers rigorously test their products and usually provide generous guarantees and servicing options.

Compare products, prices, and specifications to ensure that you are getting a top-quality product.

Generally, LED manufacturers offer a range of lights intended for different uses, from cloning through vegetative to flowering.

LED lights are expensive, and top-quality 600W or 1000W equivalents can easily go for $1,500 or more per fixture.

But with top-of-the-range HPS lights also selling for up to $1,000 per unit, the difference is not really so staggering – and as time goes on, it appears that the gap is narrowing.

If you want the best of the best, you have to pay, whatever form of technology you opt for.

With today's LEDs, the savings in electricity consumption should pay for the increased initial investment in just a few months.

My Experience – Notable Brands

Brands that I have personal experience of using and have found to produce excellent results:

Magnus ML-350 – (Red-Blue Spectrum), Dimmable, 350W, 600W equivalent. Used for veg and flower with great results.

Horticoled Xmax 3 V4 (Only used for veg growth so far) – Dimmable & Programmable (Full Spectrum), 350W, 600W equivalent.

Papillon (PL Lights) Hortiled Top – Dimmable (Full Spectrum), 320W, 600W equivalent. Veg and flower, very good results.

Papillon (PL Lights) Hortiled Multi – Dimmable & Programmable (Full Spectrum), 75W, vegetative/cloning light. Excellent results.

Papillon (PL Lights) Hortiled Inter – (Red-Blue Spectrum), 47.5W, sub-canopy light. Needs more testing.


We hope you've enjoyed reading this intro guide to LED lighting. If you have any questions or feel that we've left something out, please let us know in the comments! We’ll address your questions in subsequent articles.


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