HALP! CMH lights- what is going on?

[Thetinman]

Keeping reflection from tent around 1k extra. Open room, no reflection here. So I dropped to 7k. Really need any numbers that I can match up to at working grows with cmh lights....

 

[Frankster]

Dude, they are notoriously inaccurate. This little meter seems to work well. But no one seems to own one! Haha!

I think it depends on the light that's being used, actually. There only going to be as accurate as the light they've been calibrated too, otherwise, I think they might be just fine. It's a tool like anything else, you should not expect identical results with anything, unless your working with the same exact equipment. I don't know how much better the sensors might be, but in the cheap light meters, I suspect not too much difference. I have a fancy meter, and I have the phone, I use neither very regular, but look at the plant, instead. I also use a lot of UV spectrum light...

AgroMax Pure UV T5 Bulb – AgroMax

I also use full spectrum Samsung 301H diodes and Osram 660nm. Lights are everything, and I see great results with some CFL setup's, I'm very impressed. I also used to run a few DE CMH@1200w and made great buds, but I haven't run it in a few years and I don't have the room for it. But I'm very interested in the subject, and I think getting the plants out of the gate quickly, gives them a huge advantage down the road.

If your measuring ambient light, that might be another story, but I still think there in the ballpark, if their calibrated, and have the right algorithms. I think it's pretty much a math exercise, for the most part. That's what needs to be accurate. Different spectrum have different wavelengths and photon flux.

 

[Thetinman]

I think were talking different lingo maybe. footcandles, lumens, lux... plus everything's different, and I'm not familiar with cfl measurements, actually. I would say go up to half of your full strength, or just under....

Ya, these lights are completely different from others. Pure white light. Bright, like unbelievably bright!

 

[Thetinman]

I think it depends on the light that's being used, actually. There only going to be as accurate as the light they've been calibrated too, otherwise, I think they might be just fine. It's a tool like anything else, you should not expect identical results with anything, unless your working with the same exact equipment. I don't know how much better the sensors might be, but in the cheap light meters, I suspect not too much difference. I have a fancy meter, and I have the phone, I use neither very regular, but look at the plant, instead. I also use a lot of UV spectrum light...

AgroMax Pure UV T5 Bulb – AgroMax

I also use full spectrum Samsung 301H diodes and Osram 660nm. Lights are everything, and I see great results with some CFL setup's, I'm very impressed. But I'm very interested in the subject, and I think getting the plants out of the gate quickly, gives them a huge advantage down the road.

If your measuring ambient light, that might be another story, but I still think there in the ballpark, if their calibrated, and have the right algorithms. I think it's pretty much a math exercise, for the most part. That's what needs to be accurate. Different spectrum have different wavelengths and photon flux.

Hmmm, very interesting. Not sure how to match up with specific bulbs. Typically starting seedlings it's around 4-5k lux. But these lights are so muck different than others. Also dealing with desert conditions which might be a factor....

 

[Thetinman]

People have been talking up the CMH for seeds and clones. Never had any decent luck with florescent nor diods. Still have no idea what the strength should be as far as any measurements, cant find anybody with a lux meter...

 

[Thetinman]

To get par to lux or vice versa, use 3.04 as a multiplier or divider. So lux at 3050 is 1000 par. Par is also nm.

 

[Thetinman]

Oops 3.05

 

[TripsRabbit]

People have been talking up the CMH for seeds and clones. Never had any decent luck with florescent nor diods. Still have no idea what the strength should be as far as any measurements, cant find anybody with a lux meter...

You can download lux meters on app store.

 

[Thetinman]

Appreciated, they dont work very well though. Need a bulbous reader...

 

[Thetinman]

UPDATE!
WELL! It has been a roller coaster on a ride on this thing, so I will update you...

Now what I have done is hang 2-315cmh lights 4' apart from each other. That caused a dead spot in middle. Tied ends together, now are 2' from bulb to bulb.
Took alot of lux readings. All taken and metered 4" up from bottom of floor, clear of plants. That seemingly comes to rest at 6300lux. Not an easy find! This also includes humidity at 45-50% @72-77rh. Must keep temps below 80°! Nights goto 65rh!

Second thing I did as a standard, was hang Orca sheeting on walls. (I CANNOT TELL YOU, DO NOT EVA USE ORCA AND CMH LIGHT TOGETHER!) disaster ensued, yanked out (physically) and swaped sides to just have a flat black, not shiny. The pressed bubble wrap used for all walls also contributed to problems.
So zero reflection might be best!

Didnt give up, for one reason. The CMH lights ARE SO FORGIVING! Problems, well tweak it, it comes right back with no serious perminant injuries...
Will send pics probably tomorrow. Started growing with transporation happening so pots are just now drying out....

T

 

[MIMedGrower]

UPDATE!
WELL! It has been a roller coaster on a ride on this thing, so I will update you...

Now what I have done is hang 2-315cmh lights 4' apart from each other. That caused a dead spot in middle. Tied ends together, now are 2' from bulb to bulb.
Took alot of lux readings. All taken and metered 4" up from bottom of floor, clear of plants. That seemingly comes to rest at 6300lux. Not an easy find! This also includes humidity at 45-50% @72-77rh. Must keep temps below 80°! Nights goto 65rh!

Second thing I did as a standard, was hang Orca sheeting on walls. (I CANNOT TELL YOU, DO NOT EVA USE ORCA AND CMH LIGHT TOGETHER!) disaster ensued, yanked out (physically) and swaped sides to just have a flat black, not shiny. The pressed bubble wrap used for all walls also contributed to problems.
So zero reflection might be best!

Didnt give up, for one reason. The CMH lights ARE SO FORGIVING! Problems, well tweak it, it comes right back with no serious perminant injuries...
Will send pics probably tomorrow. Started growing with transporation happening so pots are just now drying out....

T

315 cmh recommended to place 3 feet apart. And 16” is max par. I couldn’t get one closer than 18” at peak flower. But 3-4’ overcanopy in veg.

 

[Madbud]

CMH bulbs are delicate, they have to be on at least five minutes or the mercury splatters. They were fine years ago but not my choice anymore, too hot and inefficient.

 

[Thetinman]

Ok, this is just for veg. What do you use if I may ask...
T

 

[Thetinman]

Well well well. It worked. Blacking out all walls seems to be essential. They are now turning dark green, no splotchy looking leaves anymore, no yellowing, looks great for the first time.
Now it seems that by reflecting these bulbs IS a BAD IDEA.
Let's see if they rock and roll...

T

 

[Madbud]

Ok, this is just for veg. What do you use if I may ask...
T

I’ve always used flourescents for veg but got a black friday deal on an led i’m playing with.

 

[Thetinman]

So you are still looking for the magic bulb also. Well I will tell ya this. CMH should have zero reflection. I am seeing exactly what I wanted.....now.

 

[Thetinman]

Update:
Dropped humidity to 70rh,
Dropped lights to 7k.
Getting greener, absolutely ZERO
YELLOWING. Reflection causes yellowing.

 

[Madbud]

So you are still looking for the magic bulb also. Well I will tell ya this. CMH should have zero reflection. I am seeing exactly what I wanted.....now.

Not magic just current and led was dirt cheap $55. Old school, new school

 

[Thetinman]

Jesus! That's not florescent, that halogen. I installed the same stuff when I was a contractor. For outdoor lights... That works? But I will say,

There was a customer that wanted the full boat. We installed the copper sidewalk lights in flower beds. They grew like MAD! Might be that it extended daylight hours of absorption... ?

 

[Thetinman]

One of em is a VW light for beetles...