Integrated IR + UV led arrays vs non integrated

[Growindoor]

Hi everyone, first post on this forum.

I've been reading quite a bit about grow lights, spectrums, etc. One thing I'm wondering is why some led lamps only have full spectrum led chips (like the lm301h), while other include some far red, or some IR, or some UV. And of those that include these "extra" wavelength, some include only UV, some only IR, some both, etc...

So my question is, why would someone choose one type vs another? Why go with only full spectrum while you can have IR + UV, and why choose this while you can have IR + UV + Far Red? Or on the contrary, why have a lamp that includes everything instead of having only a full spectrum ones and adding IR and UV bars in between the full spectrum ones?

Thanks for your insights,
Olivier

 

[troutman]

I have 2 SF4000 and 1 SF1000 and they all have IR at 760nm.

These videos may help you understand more.

https://www.youtube.com/watch?v=j5dWMHdUbSY

https://www.youtube.com/watch?v=Ts5zHlXRsOU

 

[Ipotato]

https://en.wikipedia.org/wiki/Emerson_effect

 

[Growindoor]

Thanks Troutman and Ipotato,

I understand the effect of various wavelength. My question was more about a technical aspect of light fixtures. Why would someone choose a light that has only white full spectrum chips and then add some IR/UV supplementary lights, instead of a light that already includes IR and/or UV and/or Deep Red led chips?

 

[Tangwena]

Thanks Troutman and Ipotato,

I understand the effect of various wavelength. My question was more about a technical aspect of light fixtures. Why would someone choose a light that has only white full spectrum chips and then add some IR/UV supplementary lights, instead of a light that already includes IR and/or UV and/or Deep Red led chips?[/QUO

edit

 

[Ipotato]

Thanks Troutman and Ipotato,

I understand the effect of various wavelength. My question was more about a technical aspect of light fixtures. Why would someone choose a light that has only white full spectrum chips and then add some IR/UV supplementary lights, instead of a light that already includes IR and/or UV and/or Deep Red led chips?

number of dedicated (IR/UV) diodes might be low (just for show so the product page can use it as a selling point) so that the actual effect is negligible

 

[BenoitV1984]

So my question is, why would someone choose one type vs another? Why go with only full spectrum while you can have IR + UV, and why choose this while you can have IR + UV + Far Red? Or on the contrary, why have a lamp that includes everything instead of having only a full spectrum ones and adding IR and UV bars in between the full spectrum ones?

Having integrated UV is a really bad idea IMO. UV chips lifetime rating is around 8.5k hours whereas the other chips are like 50-60k. If you really want UV, I would definitely suggest getting them as stand-alone so you don't end up with a part of your fixture useless after a while.

As for IR, you don't really need dedicated bars for that as most fixture have some IR chips already built-in. Our sun is giving IR mostly at sunset and sunrise, but having that same amount of IR light spent on the whole day period doesn't change anything.

 

[Vandenberg]

I just ordered a 750 watt 4'x4' bar LED light and it has its IR & UV separated with an on/off switch which enables the light to have 4 specturms.
Spectrum 1: 3000k + 5000k + Red 660nm
Spectrum 2: 3000k + 5000k + Red 660nm + IR 730nm
Spectrum 3: 3000k + 5000k + Red 660nm + UV 395nm
Spectrum 4: 3000k + 5000k + Red 660nm + IR 730nm + UV 395nm
She's going on a light rail with co2 enrichment over some auto flowers with their lower Daily Light Integral (DLI) requirements the light setup will help extend its resultant rectangle footprint even further.

We currently generally understand that:
Many of the spectrum wavelength ranges are visible to the human eye, but plants require wavelengths above and below the visual spectrum of light that includes ultraviolet (<400nm) and far-red/infrared (>700nm).

Ultraviolet Light (UV)
Ultraviolet light is comprised of three different wavelength ranges of light.

UVC (200-280nm) has the shortest wavelength and most energy, but is potentially the most stressful to plants and human skin causing sunburn and can be very damaging to human eyes. Fortunately, for humans and plants atmospheric absorption eliminates the majority of UVC shortwave light.

UVB (280-315nm) has a short wavelength, high energy and also causes sunburn in humans and plants. UVB is known to damage protein and nucleic acids in plant cells, causing decreased metabolism and decreased number of flowers. UVB can have positive effects for plants as well. Cannabis responds to the stress and sunburn from UVB wavelengths, by creating it’s own sunscreen in the form of trichomes. The more trichome production the higher the THC, CBN and CBD levels.

Exposure to UVB radiation is also known to reduce a plants biomass, plant height and leaf area, but increase leaf thickness, terpene and resin production.

Cannabis cultivators who’s main goal is to boost the amount of fragrant enhancing terpenes and oils for edible, tincture or waxes, rather than focus on high yields may choose lighting such as Metal Halide that provides some level of UVB radiation or supplement their current lighting with UVB reptile lights.

Finally, UVA and near ultraviolet light (315-400nm) has the longest wavelengths of UV light and can be very beneficial to plant development. UVA has also been shown to increase the amounts of THC, CBD, and terpene production in cannabis plants, without the negative effects of UVB.
Wavelengths in the UVA spectral range are included in the absorption spectrum, particularly in the 380nm range. The absorption spectrum is the range of wavelengths of light that are absorbed by green chlorophyll for photosynthesis. Additionally, research has shown that exposing plants to UVA light can also inhibit mold growth and fungal development.

Far-Red and Infrared Light

On the far end of the spectrum (>700nm) you find far-red and infrared wavelengths of light. Far-red and infrared light have very long wavelengths, and very little energy. Infrared wavelengths are not visible to the human eye and only can be felt as heat.

We know that blue and red light is optimal for plant development, but research conducted in 1957 has shown that combining blue light and red light with far-red/infrared light (700-760nm), led to an increased rate of photosynthesis due to the Emerson effect.

The protein Phytochrome is the only known receptor that is sensitive to far-red/infrared wavelengths. Plants use Phytrochrome to regulate when a plants is to switch from vegetation state to flowering, and the time of flowering, due to the length of daylight or exposure to artificial light.

The appropriate amounts of far-red and infrared light can also be a very effective at promoting robust stem growth, proper node spacing, and more flowers and fruit.
Too much IR radiation can also be an issue because to plant the majority of IR radiation is felt as heat. Growers who use traditional 1000W HPS lighting, which produces excess heat through IR radiation, have to install and operate expensive HVAC systems to mitigate the heat.
Too much IR radiation can cause plants to stretch spreading out the plant nodes, can discolor the leaves or even kill the plants. Choosing a light with the right amount of far-red and infrared light at appropriate times is key for healthy and natural plant growth.

Vandenberg