Will 150w HPS outperform 372w of T5HO?

OMB trust me you are more than capable of understanding PAR. I really wish growers would get PAR meters and use that as a standard rather than watts, lumens, etc. PAR (Photosynthetically Active Radiation) is a much more relevant and accurate way of measuring useable light. It ignores non-relevant wavelengths (such as green) so it gives a much more useful measure of your lighting intensity and your overall setup. PAR is a measurement of photosynthetic photon (light) flux. Having photon density in the right wavelengths will make a difference no matter what you are growing. Chlorophyll is actually found in several forms, and each of them absorb light energy at different wavelengths. There are a handful of other light absorbing pigments (eg carotenoids, xanthophylls) in plants that absorb light at specific wavelengths as well. Different pigments are more or less important at different stages of the plant's life, and in differing plant types. While it is certainly possible to "overload" a plant with sheer light intensity (scientists refer to this as "photo-bleaching"), in artificial grow operations the biggest problem with light is 1. not enough, 2. not the right kind, or 3. too much heat. The heated air near the light source is very hot, more than people would think. If you have glass in your light reflector, a layer of superheated air can form that will simply burn your plant. What a lot of people call "light-damage" is actually super-localized heat damage.

I am quite sure I can grasp the concept, I'm just not that scientific in my grow. (yet). I did look online for a PAR meter, they ain't cheap. So it looks like I won't be getting one anytime soon. It would appear the 35,000 Lumen of the T5's is fairly optimal for my space and strain, though I'm sure it could be tweaked for even better results.
The HPS lighting is attractive to me in regards to total Lumen and penetration, but I just can't deal with the heat. It's already been a problem in the winter, I'm going to have to revamp ventilation for spring and summer.
Then again....I do have a greenhouse. :)
Hmmmm....a 3rd in the comparison testing? Mother nature against the T5's and HPS? It would be interesting to see if the outdoor one's would stretch like the original mother instead of being Stumpies.

Looking good, just need to avert any catastrophes for another 2 weeks or so.

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Those are looking really nice!! Smelly?

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Originally Posted by tlranger

Those are looking really nice!! Smelly?

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Sure are ranger! That's the next issue I need to deal with...Filters. Nothing better than just touching those buds though...(Probably shouldn't, huh?) Walking around sniffing my finger's like a 15 YO boy who got to touch a girl for the 1st time. ;)

Damn dude things are really moving along nicely. I think your development may actually be slightly ahead of mine (I think you stated 12/12 just before I did? I started Nov.30th) Anyway those T5s are impressive. Tonight I'm going to install bank of 4x4' T5s perpendicular to my HPS box to get some wider coverage and side-lighting. Another advantage of your shorter plants is that the stems aren't falling over. Mine are so long that now that they're putting on weight they're flopping all over the place. With all of my tethers it looks like some kind of weird S&M session going on in there.

Yeah PAR meters are pricey. I'm lucky I can bring one home from the lab to use when I need it. Also there are a lot of junk light meters out there so you've got to do some digging for reliable user feedback before you dive in and pay for one.

Thanks chromophore! The T5's went 12/12 11/29 and the HPS one's 11/30. I am very pleased this 2nd go around. Better than the 1st, they actually got some 'nutes this time. Lol
Looking good, but dropping yellow fans daily....I'm a little concerned there won't be any left before they are ready to cut.
The HPS girls have just a couple leaves with clorosis, but they are just starting to yellow. I'm pretty sure I'm done with that little 150W HPS. I think I'm going to P/U an 8 bulb 2 foot T5HO for that end of my closet and use CFL sidelighting.
That's where the mama plant is going in 1 month, she should be spectacular. I have already been tying that Lady down, she is a bush!...and thirsty! She is so wide and tall, (relatively speaking as far as tall) she needs her own light.
Go Stumpies! :thumbsup:

Those are beautiful!

Losing a lot of those yellow fan leaves...I'm getting nervous, I'm only 38 day's in. :(