LEDs: To Use or Not To Use?

A lot has changed and improved with LED lighting since this article was first written in 2015. We now stock a range of led grow lights - check out growing lights from Telos, Gavita, Maxibright and more.

You must have heard the hype around LEDs.

There have been some bold claims – truth be told, some aren’t true – yet.

Don’t get us wrong – LEDs have promise and are getting better all the time.

We’ve got high hopes for them in the future. Even now they have their place. But right now, that’s not in our shops. Here's why.

…we seriously considered stocking them, and put them through a series of tests.

We were sorely disappointed.

The LEDs we tested just didn’t have the right spectrum or intensity for healthy growth. Plants grown under them were gnarled and full of deficiencies.

In short, they didn’t work – here are our results: Test 1, Test 2, Test 3

HYDROMAG decided to pitch the latest generation of LEDs against some bestselling HPS lights. When asked for our help, we couldn’t wait to get stuck in! We made space in our Sheffield store, and threw some of our best equipment at the test.

You can see the full test here, but in a nutshell… LEDs are starting to work.

They were able to grow healthy, deficiency-free radishes, comparable to those grown under a 600W Dimlux! Impressive. LEDs were efficient to run, too. We’re optimistic.

LEDs have poor light penetration. Light from an LED will only really reach canopy leaves – those closest to the light. The leaves below the canopy won’t get much light at all.

With radishes and other small plants, this doesn’t matter as much. For larger plants, it’ll be a problem.

Of course, this remains to be seen. HYDROMAG has promised to re-run their test on larger plants. We’ll tell you when the results are in!

All grow lights give off heat, which warms the grow room. This heat is either in the form of radiant heat (mostly emitted by the lamps) or convection (produced by the ballast, lamps and reflector), which rises.

LEDs don't give off much radiant heat. This is where the light directly warms the plant, in the same way that sunlight warms you. Radiant heat is vital for optimal growth. Without it, plants are slow to develop during vegetative and generative growth. You’ll also likely need supplemental heating to reach the optimum growing temperature of 28oC.

LEDs still give off a lot of heat via convection, but this heat rises up and away from your plants, and is often pushed away via cooling fans.

The LEDs tested by HYDROMAG cost from £800 - £1,200. For around that price, you could get this glorious combination:

With either combination, you’ll get a far more intense, spectrum rich, light for the same cost. 

• Spectrum rich: The spectrum of an LED + more PAR, UVA, UVB, Infrared & far red.
• Greater Light Intensity: You have the intensity of a 400V lighting system, with the optimum micromole output.
• Better Light Penetration: The intense light output from the HPS lighting systems will reach plant leaves lower in the canopy.

If you’re growing chillies or fruit, it’s a no brainer - UVA and UVB – enhance the aroma and taste.

Read more about light spectrum here…

In tight spaces, it is harder to remove heat.

So in very small grow spaces, where head room is limited, LEDs can be handy, because they don’t generate much heat.

We won’t rule LEDs out forever - they are getting better. They’ll soon start to get cheaper, too.

When this happens (and it’s only a matter of time), we’ll be quick to stock them.

Until then, sorry, they’re not for us.

Chat to one of our growing experts. They’ll always help you find a grow light to outperform any LED of the same cost.