I can see ONE advantage for using HID lights in your barn. They will help heat it in the winter !!!

Compact florescents ALSO contain mercury and are NOT eco friendly either !!

This is a really interesting discussion, these debates seam like they are going on across all sorts of hobbies forms and seeing the conclusions some are coming to are very educational.

I spend a lot of time on planted tank forms and the LED subject there goes round and round, and the consensus seams to be the technology is not quite there yet.

The biggest problem with LED's is not so much the wave length, it would be nice for manufacturers to figure out how many K a bulb puts out, but a lot of planted tank enthusiasts are finding lumen output is lacking in LED's, if you have a bulb that is 6500K, it is useless if you don't know how many lumens you need for what you are trying to grow and LED's are not quite there yet for the aquarium hobby. It is extremely difficult to find an LED with a lumen ratings and a lot of hobbies who have light meters find LED's don't output the lumens they need (for high light level plants) no mater how many they are able to stuff above their tanks.

If you knew how many lumens you need to grow a specific spices of plant then the most cost effective thing you can do is get a light meter. Might as well get one and be sure since LED's are so expensive, and then look for a LEDs that have or add up to the lumen rating you need. If you can't find ratings then you have your light meter to test any that you buy and hopefully you will find some that works for your set-up.

I would love to get a light meter, as I am sure my plants are not getting enough light in the winter. I am currently using shoplights in sets of two T12's in the 6500K range with the highest lumen outputs I can find but my hibiscus grows taller in the winter time and my jades get black spots, which can be a sign of light deficiency. It would be nice to know how many lumens are reaching the plants so I could get the most out of my money, especially if I decided to buy a better set up.

If what you say is right about LEDs not putting out enough lumens, keeping them at that distance will just add to the lack because lumens deteriorate exponentially the farther away you get from the source. That's why 2.5 to 3 feet away from the foliage is ludicrous ! That's the distance suitable for HID lights because they DO put out a massive amount of lumens !

Yes, that is exactly right. Which reminds me, I need to stress that is the reason why aquarium hobbyists don't use LED's. If you have a 50 gallon tank, it is at least 2 1/2 feet deep, and lumens fall off in water quicker.

However, mini-panted tank hobbyist claim that this is not true for tanks less then 30 gallons, it is actually the opposite, you need higher light output then what you think you should.... don't ask me about this, this is what a lot of them claim and I don't see where there logic comes from. I need to read up on it because it just doesn't sound right. :confused:

If you could stick LED's under water I think things might be different, but land growers have the advantage of choosing the distance form the plants the light will be so this changes their usefulness.

The next issue of Orchids magazine is supposed to have an article about LED growing by Jerry Fischer.