Adding UVA

pahpah-cee

Well-Known Member
Looks like spider farmer made the same decision and went with the supplemental uv bars.

Correct me if I'm wrong but I believe UV diodes don’t last nearly as long as other diodes. So a supplemental bar is better if you plan on running your lights for their full estimated life.
 

Grow Lights Australia

Well-Known Member
Looks like spider farmer made the same decision and went with the supplemental uv bars.

Correct me if I'm wrong but I believe UV diodes don’t last nearly as long as other diodes. So a supplemental bar is better if you plan on running your lights for their full estimated life.
It depends on the diode. UV is a large range (280-400nm) so diodes that carry less energy (UVA >385nm) can usually last for the effective life of the fixture. It also depends on the quality of the diode. As mentioned UV bars can create hotspots in the canopy because they concentrate the UV light along a narrow strip so you need to raise them higher to spread the light unless you run multiple UV bars. Too much UV can damage plants, stunt growth and have the reverse effect on cannabinoids than expected, so you do need to know how to use it properly. Some growers forget that UV stress the plant into producing more secondary metabolites (cannabinoids) but it also breaks them down. We have seen cannabinoid levels go backwards with the use of UVB/UVA reptile bulbs as the UV was degrading the THC faster than it was being produced by the plant.
 

gubblebum

Well-Known Member
Most growers are convinced that UV and IR are helpful for indoor growing - because sunlight has a lot of IR and UV - so over the past few years, many LED grow light brands have added a mix of UV and IR bands to the full spectrum of PAR (400-700nm) - and this has been a selling point for the Mars Hydro LED grow lights.

However, we are not comfortable stopping at a controversial selling point.
For years Mars Hydro has been studying whether "adding a small amount of UV and IR to the full spectrum" is a truly practical design, and we finally found the answer.

Installing a few UV or IR beads on the panel is not functional at all and can even cause damage to the beads very easily.
Only by using sufficient UV and IR radiation at the right stage of plant growth can you really take advantage of these two specific wavelengths to win the bonus - something that many growers have confirmed through experienced and skilled experts at grower forums and summits.

Over time, Mars Hydro will also be implementing this point by phasing out UV and IR from all Mars Hydro LED grow lights and instead offering a supplemental lighting series (UR45 light bars) to provide rich, quantitative, and actually effective UV and IR to assist growers in obtaining the highest quality cultivation results, taking full advantage of the precise control in indoor cultivation over environmental variables.

If you would like more detailed information of UV and IR and how to use them, please read:

Or get summarized information from the following image:
View attachment 5221265
Mars Hydro I'm a bit confused. On your guide you say to run the lights 10 on 10 off 10 on before lights out. However all the research I'm reading online states the benefit comes from running ir 10 minutes after lights off?
 

Isawthelight

Well-Known Member
I F'd up & learned UVA can burn an idiot's plants. I've got some Blue Dream photoperiod clones growing in a 2'x4' under a Grow Light Science Progrow-320 (293 watts for 12 hours) and Spider Farmer SF-UV30 (30 watts for 2 continuous hours) and pictures are at day 21 of flower.

SF-UV30 two hour on time too long.png
I've decreased the SF-UV30 to 4 minutes per hour starting with 2nd hour and ending after the 10th hour of the day. for a total of 40 minutes.
 
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