FourOaks, in my tent the temps will raise above 90 degrees very fast. I can maintain 80-83 degrees with the exhaust going. Once your over a given distance for a given wattage light there is little benefit to your plants other than some heat. My 250 watt light at 1 foot produces around 27,500 lumens. At 3 feet it only produces around 3,300. Bower, those are some very healthy looking plants. I find the same results with my LED's, much stockier plants.

[QUOTE=Tiny Tim;689487]FourOaks, in my tent the temps will raise above 90 degrees very fast. I can maintain 80-83 degrees with the exhaust going. Once your over a given distance for a given wattage light there is little benefit to your plants other than some heat. My 250 watt light at 1 foot produces around 27,500 lumen. At 3 feet it only produces around 3,300.[/QUOTE]


Gotcha. I have been looking at HID as an option. If I go that route, I am considering 2, 1000 watt units. According to:


[url]http://www.littlegreenhouse.com/guide3.shtml[/url]


I should be able to get an effective area between 8x8 and 12x12, each. I realize this is highly subjective.


Greatgardens, I didnt mean to hijack your thread. Sorry about that.

I believe your footprint is about 5'x5' at 36" from the canopy of your plants for a 1000 watt. Those big lights produce a lot of heat. Air conditioning and air cooled hoods are usually necessary. Not sure inside a greenhouse.

[QUOTE=Tiny Tim;689544]I believe your footprint is about 5'x5' at 36" from the canopy of your plants for a 1000 watt. Those big lights produce a lot of heat. Air conditioning and air cooled hoods are usually necessary. Not sure inside a greenhouse.[/QUOTE]


I believe the numbers I posted above are for greenhouse use, because you do have the Sun Light Factor. Even a cloudy day has a lot of lumens. Not sure how many without looking it up, but I know its fairly high.


The Green House in question is 24x24. Sidewalls about 6 foot tall. Center peak is about 12 foot. Im thinking the heat from the lights would benefit the environment overall.


I guess I didnt word my question quite right. What I meant, does the heat hurt the light if you dont vent it? As in, you must vent it, because it might cause long term harm to the light?

FourOaks, there's a temperature tradeoff between LED and fluorescent that I read about. LED's are less sensitive to cold temperatures and work better in cold than the T8's. But LED's are sensitive to heat on the flip side. This means if you run them in a greenhouse that gets very hot, you could shorten their lifespan.

I was thinking of putting some LED's out in my greenhouse as well, because they're tolerant of cold and also damp environments. But can't take the heat, apparently.

Bower, good points there. There is something else to consider...


Today I went to my local Hydroponics shop. I trust the opinion of the Manager. I explained my situation, although he knows I run GHs. We got talking about the HID lighting. He flat out recommended the cheap "batwing" reflector, as opposed to the expensive hood that was on display. I asked about it, he said it would be a waste of money for me. So... in essence, I trust the guy.


Anyhow, he pointed out the 1 big, overwhelming problem with LED.. what happens if the Diodes start burning out? How do you fix it? At least with HID lighting, the bulbs are always available.

FourOaks, as Bower mentioned LED won't take extreme heat. Most folks that have diodes burn out don't run an air exchange system. That's why I always run cool air intake and exhaust in my situation. I know the manufacture I use will send you free diodes if you have any burn out. I'm going on 2 years and not one bad diode yet. HID, HPS and MH are old school lighting. They do work. But, you'll pay to run them. I run a cheap batwing hood because I just wanted to run a 1 plant comparison. The light will be gifted to a friend soon.

Have you looked into CMH by any chance. It may give you the best of both worlds for your greenhouse.

Happy gardening..

Unless the warmth of HPS benefits you, or you're trying to cover a large area, they're overkill. Seedlings just don't require that much light. T12's in simple daylight bulbs (6500k) have turned out beautiful trays of seedlings for years.

[QUOTE=Tiny Tim;689695]FourOaks, as Bower mentioned LED won't take extreme heat. Most folks that have diodes burn out don't run an air exchange system. That's why I always run cool air intake and exhaust in my situation. I know the manufacture I use will send you free diodes if you have any burn out. I'm going on 2 years and not one bad diode yet. HID, HPS and MH are old school lighting. They do work. But, you'll pay to run them. I run a cheap batwing hood because I just wanted to run a 1 plant comparison. The light will be gifted to a friend soon.

Have you looked into CMH by any chance. It may give you the best of both worlds for your greenhouse.

Happy gardening..[/QUOTE]

Tim... do you know of any comparison charts that involve LED vs. HID lighting? I havent looked that hard. But I do know that no matter what, 1000 watts is 1000 watts.

Never heard of CMH.

[QUOTE=Ricky Shaw;689737]Unless the warmth of HPS benefits you, or you're trying to cover a large area, they're overkill. Seedlings just don't require that much light. T12's in simple daylight bulbs (6500k) have turned out beautiful trays of seedlings for years.[/QUOTE]

Ricky... in this case yes.

You may have missed whats going on. My seedling operation is expanding, and im combating cold gray days out in the greenhouses. So, in this instance, the heat and power of HID lighting would be beneficial.

I currently use T8s, am at the point to switch to T5s, LED, or HID.


And Greatgardens, once again, sorry to highjack your thread. You havent chimed in, so it would be interesting to see what your opinion is.

Yes I kind of picked up it was of benefit to you Four Oaks, sorry I should have been more specific. AKmark and Cole Robbie use them in much the same way, for warmth and to cover larger areas than a grower at home in heated spaces. More of just a general comment that in a lot of cases, unnecessary.

[QUOTE=Ricky Shaw;689752]Yes I kind of picked up it was of benefit to you Four Oaks, sorry I should have been more specific. AKmark and Cole Robbie use them in much the same way, for warmth and to cover larger areas than a grower at home in heated spaces. More of just a general comment that in a lot of cases, unnecessary.[/QUOTE]

Its all good, friend.


I didnt intend to hijack this thread, but see it as pointless to start a new thread, with virtually the same discussion. And your right, for most folks at home, t12s thru t8 do just dandy. Years ago I started with t12s. In 2015 upgraded to t8s. Now its time for another upgrade. And choices, choices, galore.


And honestly, I really dont know which direction to go.:lol:

This thread is really interesting even if it went a bit further than the original topic. The OP can always chime in again, if we've totally missed the point. :)
Speaking of point, there's one more difference I noticed and should mention: length of warranty on the lights. I know my original T8 fixtures had only a one year warranty. Yes they were bottom of the line, basic shoplight, with some defects I had to take care of myself when I figured it out (Those pull-down configured sockets suck, for not holding your tubes snugly and firmly in place). But I think 1-2 years is a typical warranty for fluorescent fixtures. The LED fixtures OTOH nearly all come with a five year warranty. That is pretty good for fixture plus lights included.

FourOaks, I'm not so sure I'd trust a comparison chart or graph. LED's measure light spectrum using PAR. HID measures using Lumens.

Either way old school growers will always favor HID, new growers will swear by LED.

This is why I purchased a Mars II 400 watt LED, it claims at 190 watt actual draw it compares to a 250 watt HID. I also purchased HTG's 250 watt magnetic ballast HPS for comparison.

I can verify it does produce close enough to call it a tie. I have nothing to gain from making this statement. I also know when running my HID in the summer I need to add the cost of running a small 5000 BTU air conditioner continuously. I do not need to do that with the LED. You also need to understand watt to watt is not the best comparison. The LED's spectrum is more efficient than the HID. Also,when you actually compare watts required for indoor growing, consider the air conditioner and blowers running for air exchange. For your green house those might never be necessary. Good luck and Happy Gardening.
Tim

Tim...

So in a nutshell, what your saying is that a 1000 watt LED is NOT needed to replace a 1000 HID system, correct?


You would think some mfr. out there would make it easy. Like with a simple breakdown of what equals what.

Another point in the favor of the LED is that they are self contained. Grant it, some of the HID systems are was well. Also the LEDs being a whole lot smaller.