MH lighting spectrum question

[1080p]

My friend pitched a tent (no wise cracks)

Due to time constraints he went to the closest place he could find for a MH bulb to veg with. He went to a fish store and got a 15,000 Kelvin MH bulb... he says it's very blue.

When researching i find conflicting information, i understand you want blue light for veg, but how blue ?? I was thinking he should be in the 3,000 Kelvin - 4,000 Kelvin range ??? can someone clear up what light spectrum should be used for vegging with MH ??? Is he currently doing harm by using this spectrum ??? Thanks.

~p

 

[motherlode]

seems very blue - the hortilux blue bulb is less then half that (5500 Im pretty sure)

the hortilux super blue which combines mh and hps for good full spectrum light is 3000k

I run agrosun warm spectrum MH for veg/flower for years now and IMO hortilux super blue is a copycat that costs twice as much

Id say 12k would prolly not be good for the plants

 

[Papa]

that lamp is for a coral tank.

you're right, he should be striving for an equivalent color temperature close to daylight, about 5,500 degrees kelvin.




Papa

 

[1080p]

Thanks for the prompt replies, it is indeed a reef light.

Thanks again.

 

[BayAreasFinest]

6.4k is what sunpulse uses for their "veg" light. ive used them. and they work great.

 

[kinzla34]

here's a link you may find interesting when comparing where a variety of different lamps light levels fall into PAR ranges. The red line at the bottom of the graph represents PAR.



Cheers!

 

[1080p]

Thanks, whats the significance of "PAR" what exactly does this mean ??

Parabolic Aluminized Reflector ?? an Outdoor rated light ??? or are you just wanting me to look at the spikes (red line on graph) that i'd imagine represents good peaks for plant growth ??

 

[Melvan]

You could have just gone to walmart and got cfls to veg with, and still met your time constraints while having the proper light.

 

[1080p]

I hear you Melvan, like i said not my grow... just helping a friend out. He lives in the boonies... so when he's in town he gets extra giddy and want's to throw money at things while he can. He didn't research anything or think to ask me... I even have a 4ft t5 he could have used.... The "fish store" won't let him return the bulb, he's now stuck with a $100 dollar 10k lamp for corals.... He's now vegging with with a 600w HPS. Might be a little much... but it'll have to do.

 

[homebrew420]

those high levels of blue have been claimed to increase resin production at the end of flower. No idea if there is any truth to this claim. Sun pulse lighting is where I heard this. Don know much but I don't really see the value in a 100 bucks for an extra lamp that will make, imo, very little difference. What I am saying is it could still be used for end of flowering. Not a total lost...maybe

Peace

 

[Hydrobaby]

2700k to 3400k is for flowering
5600 to 6500 is for veg

 

[Seamaiden]

Thanks, whats the significance of "PAR" what exactly does this mean ??

Parabolic Aluminized Reflector ?? an Outdoor rated light ??? or are you just wanting me to look at the spikes (red line on graph) that i'd imagine represents good peaks for plant growth ??

Photosynthetically Active Radiation. There is also PUR--Photosynthetically Usable Radiation.

The reef light your friend bought is designed to both mimic equatorial sunlight as it passed through water (this is why deepwater animals are often vivid red, it's the first color of the spectrum to be lost as sunlight passes through water) and to bring out the fluorescent colors of many corals and other photosynthetic animals. I would be willing to go as high as 10,000K, but when you're hitting those really high numbers there may not be enough light in the other portions of the spectrum to really be usable for growing terrestrial plants. I have read others mentioning actinic lighting having a place in growing, I have two bulbs that I haven't rigged up for that just yet, so no experiments on my side. Actinic lighting is lighting that produces an extremely tight spectrum of 420nm-430nm.