Flower with T5s?

[Roddy]

LOL PawPaw, If you're throwing ideal spectrum at a plant that isn't feeling it, you're just wasting time, money and good beans! Not trying to irk you, my friend, just trying to help.

 

[pawpaw]

No problem, I do appreciate the help.

 

[The Hemp Goddess]

Just as lumens don't mean squat if they are in the wrong part of the spectrum.

Not entirely true. I have seen wonderful grows where they used MH through the whole grow or HPS through the whole grow.

 

[pawpaw]

The first graphic below shows the relation between wave-length and relative photosynthetic activity. I have superimposed that response curve over what I call the "wrong spectrum" and both LPS and MH spectrums which shows why the latter two are not wrong though not ideal. The photo synthetic inefficiency of the LPS is especially exaggerated because the PAR graph is relative. It's actual inefficiency is closer to 50% which is to say that half the lumens produced by a LPS bulb are wasted.

 

[Growdude]

The first graphic below shows the relation between wave-length and relative photosynthetic activity. I have superimposed that response curve over what I call the "wrong spectrum" and both LPS and MH spectrums which shows why the latter two are not wrong though not ideal. The photo synthetic inefficiency of the LPS is especially exaggerated because the PAR graph is relative. It's actual inefficiency is closer to 50% which is to say that half the lumens produced by a LPS bulb are wasted.

LPS bulbs are never used for growing because of this.

 

[pawpaw]

Yea, but its spectrum is more complicated and to say anything acurate about its efficiency I would, for starters, have to take a difference between the definite integral of its curve and the PAR curve but the bulb's curve is not continuous over its range and therefore not analytic-- so I cheated to make my point

 

[WeedHopper]

OK,OK,,Use the damn LEDS.

 

[pawpaw]

OK, but now I have to eat humble pie. Thinking it over I see that what one would have to integrate is the product of the PAR and the intensity spectrum of the lamp. The first stab at this was off the top of my head and is just plain wrong. But I often get things wrong the first go round.

 

[Locked]

Yea, but its spectrum is more complicated and to say anything acurate about its efficiency I would, for starters, have to take a difference between the definite integral of its curve and the PAR curve but the bulb's curve is not continuous over its range and therefore not analytic-- so I cheated to make my point

I got smoke coming out my ears after reading that one.... You strike me as the engineer type pp....college educated for sure. I watched a documentary on string theory once and damaged my brain trying to follow along......lol.

 

[Growdude]

Yea, but its spectrum is more complicated and to say anything acurate about its efficiency I would, for starters, have to take a difference between the definite integral of its curve and the PAR curve but the bulb's curve is not continuous over its range and therefore not analytic-- so I cheated to make my point

You do know that the info you presented was on a LPS light not a HPS light?

My advice is dont get 'hooked" by PAR, so far nothing beats a HPS for flowering.

 

[WeedHopper]

If I could just get Par when Golfing Id be happy. Smoke from the joint always gets in my eyes when I tee off.

 

[pawpaw]

You do know that the info you presented was on a LPS light not a HPS light?

My advice is dont get 'hooked" by PAR, so far nothing beats a HPS for flowering.

Yes and yes though I had hoped that LED luminance values werereaching levels that would make them equal or superior. But apparently notyet. See next post.

 

[pawpaw]

Though this brouhaha over spectral distributions may seem academic, a rating for lamps in terms of photosynthetically effective lumen output would be very useful and a value functionally equivalent to the simple mathematical approach outlined above could be done by a simple computer program if one has and is willing to input the power spectrum data of a light.

The advantage of LEDs is that they are available in narrow spectral distributions set at the peak photo synthetic active wave lengths. Further their intensity values are easily varied by controlling their current draw. Thus the same unit could be used for both stages of growth. Their problem is that their lumen per watt values are still too low. This limitation is practical not theoretical and it is a virtual certainty that their efficiencies will continue to improve until they become the only game in town.

And yes I've had one foot in the hard sciences* all my life and am attracted to rigorous quantitative approaches to virtually every thing and I am in complete sympathy with your (Hamster's) signature.

*But biology/botany is a new area for me.

 

[Pistil Pete]

You do know that the info you presented was on a LPS light not a HPS light?

My advice is dont get 'hooked" by PAR, so far nothing beats a HPS for flowering.

I get nice results useing a combo of mostly hps, and some MH, that way you get the blue end of the spectrum, and you get the orange end of the spectrum outta the HPS. As far as increasing the intensity,the obvious of course, the lower the light the more intense. So buy a good fan for your air cooled reflector, and increase the intensity.For every foot away your lights are, you lose a tremendous amt of energy that is needed for photosynthesis to take place.
i hope someone can use this advise. Pistil Pete

 

[HomieDaGrower]

I went with a T5 for my veg room. It came in this morning, and I set it up straight away. I had started my plants under a 4 foot T12 fluorescent, and thought they were looking good. After 10 hours of T5 veg tubes, they have really jumped into gear. Much healthier looking, and looking stronger as well. I don't think that the T5 would have the penetration that I am looking for in flowering though. For flowering I will still use my cooled HPS 400 watt. Though I might add a T5 fixture for side lighting.

HomieHogleg

 

[Locked]

I love my HO T5's....for veg. Like Pistil Pete said...air cooled HPS and get it right down on them. I just don't see T5's getting it done penetration wise. I will stick with HPS for flowering and let T5's handle the veg. Jmo

 

[Hushpuppy]

Hey Hammy, If yu liked string theory, I bet yu would love statistics. I think the same people came up with the both of them because they both will melt your brain worse than any THC.

I could be wrong but my theory is that it comes down to energy. The plants need the energy that is transferred when photons of light strike the chloroplasts in the leaves... It is, of course, absolutely necessary that the spectrum of the light be in the area that the plants need. That is why yu can light up yer grow room with 'tru-green' light during the dark period without disturbing the plants, as they don't see it regardless of the lumens of output from those bulbs.... The bad thing with the current LED technology is that they can't or haven't produced any single LEDs that transfer enough energy from electricity to light energy(photons). I think that they are efficiently transferring what they can but they are only able to work with small amounts of electrical energy. When they start making LEDs that pull 50watts each (without costing $500 each) then we will see LED lighting used widely in horticulture.

 

[pawpaw]

I just don't see T5's getting it done penetration wise. I will stick with HPS for flowering and let T5's handle the veg. Jmo

I'm sorry to say I think your opinion is justified--for the time being. I'm just too heavily invested in my current path to go to another, at least for my first grow.

 

[The Hemp Goddess]

I don't want to sound like a ****, but why did you invest so much into LEDs without knowing how they would work? I only ask this because you seem quite intelligent--far smarter than I am...

 

[The Hemp Goddess]

I don't want to sound like a ****, but why did you invest so much into LEDs without knowing how they would work? I only ask this because you seem quite intelligent--far smarter than I am...

LOL--I didn't have a clue that d i c k was a **** word.