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Sprout & Spectrum

Do Grow Lights Emit UV?

Mostly no, on the published numbers — and the ones that go lower say so. Here is what each spec sheet we could find actually states.

By Scooter M. — An enthusiast who's genuinely into this. I read the manuals, compile the published specs, and do the math. No lab coat.

Published · How we pick

A macro photograph of a green leaf surface under bright light

The reasoning

No product recommendations on this page either. It is a safety question and the answer should not be paid for.

Where UV sits, and where grow light spectra start

Ultraviolet is light below about 400 nanometers. Visible light runs from roughly 400 nm (violet) to roughly 700 nm (deep red), and the photosynthetically active range used in horticultural specification — PAR — is conventionally that same 400 to 700 nm band. Far red, around 730 nm, sits just past the top edge.

That matters because when a manufacturer publishes a spectral range starting at 400 nm, they are describing a fixture whose stated output begins at the bottom of visible light: above the UV band, not inside it.

What each fixture we cover actually publishes

Published spectral information, quoted as the manufacturer states it
FixturePublished spectrumUV mentioned?
SANSI 36W BR304000 K, 400–780 nm, CRI close to 100No — the stated range begins at 400 nm
VIVOSUN VS1000380–780 nm, including 660 nm and 730 nm; 3000 K and 5000 KThe stated range starts at 380 nm, just inside UV-A; VIVOSUN does not characterize it further
Mars Hydro TS 1000660–665 nm, 730–740 nm, 3000 K, 5000 KNo UV band published
Spider Farmer SF1000650–665 nm, 730–740 nm, 2800–3000 K, 4800–5000 KNo UV band published
AC Infinity IONBOARD S22Samsung LM301H, plus 660 nm, 730 nm, 3000 K, 6500 KNo UV band published
Soltech Aspect Gen 23000 K warm white, CRI 98No UV band published
Barrina T5 4ft5000 KNo spectral detail published at all

The pattern is consistent: consumer white-LED grow lights are overwhelmingly specified as visible-range fixtures. Where a range dips to 380 nm, as VIVOSUN’s does, that is the very edge of UV-A and the manufacturer publishes no intensity figure for that portion — so we can report the stated range and nothing more.

Why white LEDs mostly do not produce UV

A white LED is a blue emitter — typically around 450 nm, comfortably inside visible light — under a phosphor coating that converts some of that blue into longer wavelengths. Neither half of that arrangement produces meaningful ultraviolet. Producing UV requires a dedicated UV-emitting diode, which is a separate component a manufacturer would have every commercial reason to advertise, since UV supplementation is sold as a premium feature.

That is the strongest inference available from the published data: if a fixture had UV diodes, the marketing would say so.

Fixtures we cover that advertise UV emitters
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Not one of the nine fixtures on this site publishes a UV diode or a UV output figure. Several publish no spectral detail at all, which is its own kind of answer.

What we cannot tell you

We have not measured any of these fixtures, and no manufacturer we checked publishes a full spectral power distribution chart. So the honest limit of this page is: on the published specifications, these are visible-range fixtures with no advertised ultraviolet component. That is a statement about documents, not about a spectrometer reading, and we are not going to dress it up as one.

If UV output specifically matters to you — for a plant that needs it, or because of a health concern — buy from a manufacturer that publishes a spectral chart, and treat the absence of one as the absence of information.

The related safety question

The hazard people are usually thinking about when they ask about UV is eye exposure, and for white LEDs that question is about blue light and cumulative exposure rather than ultraviolet. That is handled in are grow lights safe for eyes and pets, which walks through what the IEC/EN 62471 photobiological safety framework actually classifies.

Questions people actually ask

+Do LED grow lights emit UV light?
On the published specifications of the fixtures we cover, no. Their stated spectral ranges begin at or above 400 nm, which is the bottom of visible light, and none advertises a UV diode. One publishes a range starting at 380 nm without characterizing that portion further.
+Do plants need UV light?
Standard indoor growing does not require it — the photosynthetically active range used in horticultural specification is 400 to 700 nm. UV supplementation is a specialist topic with specific applications, and it is sold as a distinct premium feature rather than being present by default.
+Does 'full spectrum' mean UV is included?
No. The phrase has no standard behind it and does not commit a manufacturer to any particular band. Most fixtures marketed as full spectrum publish a range beginning around 400 nm.
+How would I know if a light emits UV?
The manufacturer would tell you, prominently. UV emitters are a cost and a selling point, not something a brand adds quietly. Absent a published spectral power distribution chart, the absence of a UV claim is the best evidence available, and we treat it as evidence about the documentation rather than a measurement.

Sources

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Where this sits

This page belongs to Spectrum and PPFD, Honestly. Every figure on it is either quoted from a named published source or derived in view — the full method is on our methodology page, and how the site is funded is on the affiliate disclosure.