lighting I've been thinkin'....and that was my first mistake. Indoor Lighting Help.

[GA Growhead]

Yo king, how about a ventilation system. If the area is enclosed, with a fan and ducting you can expel the hot air out. You can even rig it so the air is circulated inside the shed while cold, half and half as temps warm, and completely out in the hot summer. All lights generate heat. So put in what you want and work around it.

 

[bushwhackxj]

http://www.simplyhydro.com/article_6-6.htm

Thats a link i found. its not the most useful for exact numbers... but gives an approximation for MH and HPS bulbs, whereas there is no mention of a PAR rating for flourescents... it does explain the uses for each though. could come in handy. hope it helps, cheers

also i just checked my HID's and didnt see any PAR ratings but i seem to remember seeing the actual PAR rating and Spectrum graph right on the packaging for HID's designed for growing in the past.

 

[3/5King]

The best way I have found when buying bulbs online is to look at the output spectral graph that the manufacturer usually provides and compare it with the PAR spectrum. I think King is right that color doesnt mean much as you can mix different frequencies to come up with the same color, say 2700k. But I also think that you still know a light at 2700k will be more red and therefore better at flowering than a more blue light if all else is equal. Lumens are what the human eye sees best and is basically green light. Theres a graph for this if you need to see it. A light can a really bad spectrum and have that little bump in the right area and suddenly go from 300 to 3000 lumens from one added phosphor. It wont grow anything nearly as well as well as a "dimmer" light, measured in lumes, that as a more balanced spectrum.

I think people forget that in the PAR spectrum which basically goes from 400 to 700nm the plant is photosynthetically active the whole way across, from to blue to green to yellow, orange and red. The main difference being HOW reactive it is to which spectrum. HPS has a really bad spectrum compared to PAR if youve ever looked at it. Yet it still grows great plants. As does MH with an equally bad spectrum. The difference being which ends of the spectrum they mainly produce.

This leads me to the other thing people mostly forget. Plants adapt. If you can give them sufficient POWER with even a little PAR you can see decent results.

So to me its this simple, more power somewhere in PAR, equals better results. But if you try to get your PAR in green youll need relatively twice the power as the plant is about half as reactive at this frequency. But blue or red, as HPS and MH have shown us, will yield better results. Even a relatively low powered fluorescent light putting out decent PAR watts will grow a decent plant even at 1/10th the lumens of a 400w HPS.

What I look for is power and spectrum. Temperature doesnt matter so much, temp is more a factor of the spectrum anyway. People touting one kelvin temp over the other may want to look at what spectrum these bulbs are putting out.

Besides power and spectrum the other thing I check is CRI (Color rendering index). This is based on color reproduction of what youd see in the sun. A bulb wih a cri of 70 compared to one that has a rating of 91 wont be anywhere near as good, with everything else being equal. Compare a MH to a Ceramic Metal Halide, first the CRI, then the spectrum. Most of the important things are tied to each other. If a bulb can make colors look like they would in sunlight there is a reason.

I was going to only give you my 2 cents but I think I gave you like 30 cents or so.

For me its power * spectrum and the CRI. Theres no silver bullet and even picking out "the right" light can become time consuming.

Great answer! Some good information and deals with some points that I was trying to get across in my OP. That two lights with the same Kelvin and wattage could produce different results.

Thanks for posting and Welcome to the forum. I'm sure you will make some nice contributions around here.

Yo king, how about a ventilation system. If the area is enclosed, with a fan and ducting you can expel the hot air out. You can even rig it so the air is circulated inside the shed while cold, half and half as temps warm, and completely out in the hot summer. All lights generate heat. So put in what you want and work around it.

My buddy doesn't want to cut holes in the roof (or anywhere for that matter) for the vents and our height restrictions don't allow us to hang the HID's high enough anyway. That's why we're just going to stick with the Fluoros for now.

http://www.simplyhyd...article_6-6.htm

Thats a link i found. its not the most useful for exact numbers... but gives an approximation for MH and HPS bulbs, whereas there is no mention of a PAR rating for flourescents... it does explain the uses for each though. could come in handy. hope it helps, cheers

also i just checked my HID's and didnt see any PAR ratings but i seem to remember seeing the actual PAR rating and Spectrum graph right on the packaging for HID's designed for growing in the past.

Thanks BW. I'm about to hit up an Insanity workout but I will for sure check out your link when I get back.

 

[GA Growhead]

I know your settled but just remember you can ventilate down or out a door. Doesn't have to be the roof when moving air. Good luck with the space!