Combining HPS & MH lights

[jimbojones5678]

If you were to combine three 1000W HPS light with one MH 1000W to get a better spectrum of light, where would you position the MH? based on the diagram below?

 

Jimbo

 

And yes... I know the shades aren't facing the correct way...

[Luke Skywalker]

Perhaps having the MH in the middle and running the hps 1000's in a circle 120 degrees apart?

[SukonmiSkunk]

well setting up a room of this size.. you might as well do it right... its an awkward sort of room to illuminate.. i would suggest 6x 600.. which would be somewhere around the maximum lighting youd want for this room..

 

how ever.. you already have 3 x 1000HPS.. heres a pic of how i would position them..

 

using your pic...

 

 

 

id go for the 4 x 1000hps... maybe placing the MH in the middle...

 

with only 3 HPS's and one MH.. its hard to position the light right where it should be... as its an additional light.. to ad the extra blue.. it wont really fit in the room cemetrically.. and really.. where ever you place it.. the buds below will recive more MH than HPS.. so.. they wont be like the rest of the room... personally id leave the MH out.. if anything.. ad it in the center...

 

position the lights like i have shown will get a more even spread through out the room.. im guessing youre using a rectangular shade??.. again.. i think youd be better opting for the Parabolic shade to help spread the light into the corners a little better.. but really.. rectangular shades in here, positioned like this should work fine..

 

Edit: got me fucked why the pic hasnt shown.. youll have to download it..

[Al B. Fuct]

Personally, I can't see the point of mixing MH with HPS. In flowering, the plant wants mainly red-orange light as that mimics late summer and autumn sunlight.

 

The plant would appreciate MH in veg, but I suspect it either wouldn't care about a MH in flower or it might even try to grow some veg characters in flowering. Don't know. Never tried to flower with a MH.

 

Conversely, I veg my mums with an HPS all the time; the result there is about 1/3 more stretch in the mainstems than you get with MH. That's OK for me because I want tall clones for my SoG. Other ppl may want a more compact plant and should use MH to veg as usual.

 

Anyone flowered solely with an MH?

[SukonmiSkunk]

yeah, when i first started growing everything was done with MH.. HPS's just werent around.. and when they did come in.. they were worth about 800$$ for a kit... so i grew for about 18months with just the MH... it still flowers fine... not as filled out as the HPS.. a room with a 1000 watter in it..yielding 2-3 pounds.. youd probably get an extra 5-8 ounces(could be more) with the HPS in flowering over a MH... so yield wise its not a real big difference.. but it is a difference...

 

what i was told when i first started .. was, if using a MH for veg.. youd leave that in and just ad the HPS for flowering... as you tend to need more lumins for flowering... the thing is.. with using growboxes... most people already have the optimum to maximum lighting in there.. so adding another light is impossible ... also the cost of running another 1000 just doesnt seem viable...

[godonacid]

hps light also have no uv spectrum, while metal halides have a small amount of uv in them, in general for best all round production a lot of people say for veg run say 2x1000 watt MH and 1x1000 HPS, then for flower swap, 2x1000 HPS and 1x1000MH, and then keep stepping it up from there, 4xMH and 2xHPS for veg then swap 4xHPS and 2xMH.

[Al B. Fuct]

hps light also have no uv spectrum,

 

Sorry, not true. Where'd you get that idea?

 

HPS lights pound out a ton of UV from the tube's arc. If you don't believe me, take a look a piece of non-UV stabilised plastic exposed to HPS for a couple of months. It will bleach and go brittle.

 

Failing that, have a look at the spectral output of an ordinary HPS:

 

http://www.progressivegardens.com/growers_guide/EYE_HPS_conversion_graph.gif

 

UV is on the far left in this graph, 400nm and down.

 

For comparison, here's the sun:

 

http://upload.wikimedia.org/wikipedia/en/thumb/4/4c/Solar_Spectrum.png/400px-Solar_Spectrum.png

 

The relative UV % content of the sun and HPS are very similar.

[godonacid]

ok not none but such a small amount that it is almost worthless, have a look at how much a halide puts out or even a retro fit globe.

[Al B. Fuct]

Yes, MH puts out more UV than HPS. However, MH mimics early season light, where the solar angles are higher and the sun is 'looking' through a thinner layer of atmosphere. Both blue & UV are filtered less going through a relatively thin layer of atmosphere and thus are stronger compared to red-yellow in spring and early summer.

 

Later in the season, when the sun is at lower angles ref the surface, UV & blue are both filtered through the longer path through the atmosphere (and dust... and water droplets... and... etc), giving the apparent red-yellow colour of late summer and autumn sunlight.

 

Under natural circumstances, the plant will get less blue/UV and a progressively more red-yellow weighted spectrum as the season wears on.

 

Photoperiod is the main determinant of the plant's growth mode. You can veg with HPS and SS has flowered with MH. However, it occurs to me that I'm replacing sunlight which has certain characters caused by seasonal variations. I'm trying to trick a plant into a certain behaviour caused by those seasonal variations. Therefore, it makes only good sense to mimic those sunlight conditions as closely as possible. HPS does that for late summer sunlight fairly well, including the proportion of UV.

 

There's a rumour out there that extra UV adds resin or THC or karma or some such shit, but I haven't actually seen the peer reviewed papers on that. Other conventional wisdom is that resin and/or THC is the plant's defence against UV... which makes absolutely no sense at all, as the plant is making the most resin in late summer when the flowers are bulking up, when the plant would have less UV to defend against than at any other time of the growing season. Maybe UV suppresses resin production!

[godonacid]

in the end plants will use blue light during flower, i have seen pictures of rooms in Holland where they use nothing but MH and have a mate who still flowers under MH, his buds get a lot more cyrstal on them than mine but that could be because he uses a few 1000 watts and i dont use any where close to that, however my buds are usually denser and thicker, his still have a slightly stronger stoned (funny thought i always like his buds and he always likes mine)

 

as i said in an earlier post IMO plants will grow better if there is some red in the veg and some blue in the flower, using 2 for 1 MH to HPS for veg and 2 HPS and 1 MH for bud you will get a better quality smoke, and more uniform buds and growth, you might loose out a little weight but personally i like quality over yield.

 

any how below is coppied from advanced nutrients light guide

 

 

Because of their colour spectrums and wattage outputs, Metal Halide and High

Pressure Sodium lamps are the most popular artificial growing lights. High Pressure

Sodium lamps are strong in the orange and red spectrum bands. The HP Sodium lamp

emits an orange-like glow that is sometimes compared to that of the harvest sun.

These colours promote flower production and stem elongation. When using an HP

Sodium lamp, flower production may increase by 20% or more. Unfortunately, HP

Sodium lack in the blue portion of the spectrum. Conventional HP Sodium lights

should not be used alone, since their lack of blue light will make plants tall and

spindly. When used in a greenhouse setting, however, HP Sodium lamps are all that

are required, since sunlight provides all the blue light necessary.

 

Metal Halide lamps have a fairly balanced colour spectrum, with a higher percentage

of blue and violet light rays than HP Sodium lamps. Therefore MH lamps are

excellent during the vegetative growth stage. MH lamps help keep plants shorter and

stockier, with more compact vegetation. Stockier plants are stronger, better able to

resist disease, and generally more productive, than spindly plants.

 

When clear Metal Halide and High Pressure Sodium lamps are used together, a

 

winning combination is achieved. Blue light in the Metal Halide promotes strong

vegetative growth, and the red light in the High Pressure Sodium lamp promotes

strong fruiting and flowering. Some growers like to use a carousel system (a kind of

light mover), alternating MH and HPS lamps, to provide a balanced light spectrum

during the plant's complete growing cycle. Both Metal Halide and High Pressure

Sodium lights belong to the HID group of lights, since they are High Intensity

Discharge lights.

 

Some local growers prefer to just use HPS lights, or a certain kind of HPS light (Son

Agro) that has been enhanced with additional blue end of the spectrum illumination.

They mostly do this for budgetary reasons, as well as wanting to simplify the process,

not having to change bulbs and ballast. They claim that by keeping the lights as close

to the tops of the plants as possible, perhaps using an air-cooled lighting system to

achieve this, they keep the plants from getting spindly under the HPS lights. They

might even use blue spectrum fluorescents as side lighting, in order to help the

vegetative growth. Advance Nutrients sells a line of air-cooled shades, which

technical advisor Mike Mitchell claims are as good as anything on the market.