220w CFL 4'x4' floor plan, superior to 400w HPS

Originally Posted by TeaTreeOil

If spectrum is secondary, and I'm not saying it is, why are all the HID-fans growing under low pressure sodium? 200 lumens/watt. 142% output compared to the highest efficiency HPS.

Oh, right. They don't. Why? Spectrum output sucks.

Have you seen grows under Hortilux BLUE MH? They stomp HPS in every way imaginable.

Even two lower efficiency MH & HPS bulbs(say 400w each) versus a single 1000W HPS. The duo will champion, using less lumens, but an impressively full spectrum.

Spectrum is a trade off for intensity. Bulb manufacturers make the choice between lumens/watt and PAR/watt(PAReff). The two are linked inversely(given ideal conditions, and not just cheap materials). You can increase lumens/watt and sacrifice PAR/watt or vice versa.

This is demonstrated by HPS. The bulbs are quite similar to LPS. The major difference is the high pressure broadens the spectrum from monochromatic to a much, much fuller green/yellow/orange/red. 60 lumens/watt is lost due to this, but the result is a lamp capable of growing plants. And color quality(CRI) in the 20's or 30's compared to nonexistent(LPS), pretty much.

EDIT: Figure I'll compare MH with these just to be concise as possible.

Metal halide lamps produce a high quality of light, typically 80's to 90's(CRI). This is also why they have lower lumens/watt. The spectrums of most MH are quite full, and even offer UV(making those 'other' UV lamps pointless to HID growers).

MH's are really great! And they're far surpassing HPS in terms of technology. Because who wants to have to use an ignitor, really? They come in color temperatures from HPS-like 3000K to ultra-blue 20,000k. And range widely in lumens/watt as they can produce vastly different spectrums and intensities(65-115 lumens/watt).

Newer MH's are actually outputting spectrums damn near perfect CRI quality. Not saying this is good for plants, PAR is the only end-all-be-all, as it's a RAW measure of radiant energy(spectrum-useful energy 400-700 nm) per area. Usually expressed in similar form to: moles per sq meter.

hid fans are growing plants under High pressure sodium not LPS even though LPS give more lumans than HPS they do not make LPS lamps over ? i think 200w? they are shine a very narrow light as we know in the yellow spectrum but they will still grow plants much taller than a CFL light could watt for watt the color of light play a part in how a plant will grow more blue the shorter the nodes the more yellow red the light the taller it will grow the more light you give it in all the colors will grow a plant bigger.

as you can see a plant will grow with yellow light it does not need to be blue or red thats why HPS grow bigger plants that yeild more than CFLs because HPS intensity is so great and the spill over of the other colors have an effect on plant growth.

p.s
show me large grow rooms where they only grow cannabis in us anythig other than HPS. differant plants like differant light cannabis yeilds more in the flower stage uder HPS than under MH fact even though the MH as bettre light spectrum for plant growth over all, but when it comes to cannabis they love the red light over blue wich is good new for HPS growers the get more light for the $$$'s they spend = bigger yeilds.

I think you're confusing tall plants for big(as in foliage) plants. CFLs and MH grow super tight nodes and result in bushier(bigger) plants.

If you take a look at 1982's T5 grow you'll see this lush bushy growth. Then go look at say, RandyRocket's 12/12 from seed under HPS. Sure, Randy's plants healthy and are ~43" tall at 50 days, but the internode length is massive.

Originally Posted by TeaTreeOil

I think you're confusing tall plants for big(as in foliage) plants. CFLs and MH grow super tight nodes and result in bushier(bigger) plants.

If you take a look at 1982's T5 grow you'll see this lush bushy growth. Then go look at say, RandyRocket's 12/12 from seed under HPS. Sure, Randy's plants healthy and are ~43" tall at 50 days, but the internode length is massive.

i agree, but randys plants will yeild more if both sets of lights are use properly. you talk about par in such a way that plants will only grow in red and blue light that is not the case otherwise HPS would be shit compeared to CFL's and MH lamps, but in fact the opposite is true. HPS yeild more bud than MH light even though The PAR rating is much worse than the MH why is that? intensity of the light and the over spill of other colors of the spectrum. nothing yeilds more in flowering stage of cannabis than pure HPS light that even goes for son T agro bulbs. iv used both son T agro and raw HPS i use only raw HPS now because my tests have proven to me that i get more yeild of bud from them and dont need to change them as often as the son T bulbs. i can prove tommorow that i have son T and normal HPS lamps and have used them both. i only veg my plants under blue light for 3 to 10 days after that there is no need for blue light because they are in flower and pure HPS out yeild any other lamp when it comes to the flowering of cannabis.

how much did that cost you?

I think you're confusing tall plants for big(as in foliage) plants. CFLs and MH grow super tight nodes and result in bushier(bigger) plants.

my be that is the down fall? the tight, bushier the plants the less light penetrates the canopy?where hps do have a bit of a stretch and grow less leaf and more bud because of it? after all we are growing buds and not salad.

But light decays according to: intensity = lumens / distance(feet) ^ 2. So taller plants are going to get less light no matter what.

Here's RandyRocket's HPS 12/12 grow: 12/12 From seed to Harvest (1 oz Honies)
Here's 1982's T5 grow: lowryder 2 under 540watts t5 hydro

For Randy's,

43" = 3.58 feet
i = 40000 / 3.58 ^ 2
i = 40000 / 12.84
i = 3115 lumens.

In the light was exactly on top of his plants, the bottoms would receive 3115 lumens(perfect reflectivity).

For 1982,

I'm not exactly sure of his bulb lumen ratings But they're close enough to be additive so the light received is greater than any one bulb. Figuring a 23w t5 outputs around 2000 lumens, times 4, he has about 8000 lumens within a foot, so actually the intensity increases!

i = 8000 / .17 ^ 2 (two inches)
i = 8000 / 0.0289
i = 276,816.6 lumens

This would be if all bulb where within 2 inches on a single plant and directing their light into a condensed area.

Instead it's about a 2" average from bulb to top, this range is 69,204 lumens.

Say his plants are 1/4 the height. So instead of 4 feet we get one foot.

i = 2000 / 1 ^ 2
i = 2000 / 1

So even at one foot 2000 lumens is achieved(perfect reflectivity).

So even a low wattage fluoro can support plant life(1/5th noon soon) within a foot.

I've noticed that directly under 26w CFLs plants are stunted and grow extremely tight.



The left is 4" away minimum, the right is 2" away. The left is 6" tall. The right is 3" tall. They have almost the same number of nodes. They seem at least twice as tight on the right.

Originally Posted by TeaTreeOil

But light decays according to: intensity = lumens / distance(feet) ^ 2. So taller plants are going to get less light no matter what.

Here's RandyRocket's HPS 12/12 grow: 12/12 From seed to Harvest (1 oz Honies)
Here's 1982's T5 grow: lowryder 2 under 540watts t5 hydro

they are clearly sativa dominant plants i bet they will take a lot longer than 8 weeks to finnish and they will still yeild more than the CFL grow. sativa plants grow tall and streatch like crazy large spaces between nodes and most people will flower from seed and end up with 6 feet plants and then he should be using 1000w for best results.
Relative size of cannabis types.

as you can see stiva grow tall and ruderales grow very small lowryder are ruderales auto flowering plants

I never said HPS will under harvest lower wattage CFL. The main point is quality. Having just enough light. Rather than more than enough. Light degrades THC, after all.

A lot of CFL growers don't have proper reflectors and are wasting over half their light!

Even the example you posted:
1) Different reflectors. This is critical.
2) Lowest efficiency CFL used.
3) It's soil. Soil varies, it's just a fact.

Those are my three biggest problems with your example. In no particular order, really. They're all significant.

If you set-up a hydroponic garden so the nutrients could be consumed nearly identically... and the plants were all equal node clones... and the highest efficiency fluoros used.... We'd probably see a much better(fair) comparison.