I plan on using 2 400watt lamps side by side. Originally I was going to do two HPS bulbs but now I'm thinking it might be better to use 1 MH bulb and 1 HPS bulb to get a fuller spectrum. What do you guys think? Will the MH bulb help at all or should I just stick to the two HPS bulbs I have now? Also, what would happen if you put a 1000w bulb into a 400w ballast? Would it just not light up fully?
I think the ratio of MH to HPS is either 1 HPS to 2 MH, or 1 MH to 2 HPS. I don't remember which is the best to use.
if heat and power useage arent a issue, do wahtever you want. i prefer to only use one or the other for power and heat reasons. oh ya and read this guys tutorial on lighting you can pretty much skip the first 3 posts; and look at the 4th post. in that 4th post you'll see a bunch of pictures. the thirrd picture is the most important one; it shows you what color spectrums of bulbs (temp in kelvin) produce the most chloroplhyll activity. http://forum.grasscity.com/absolute-beginners/216418-introduction-lighting.html either way u do it will be fine, as long as theres enough light for the space.
Why would you want to run them both eh? Just use the metal halide while you are vegging amd the HPS while you are flowering. I'm growing 12 plants with one in a small space. You don't need them both. Get a combo or hook them both up and use one and then the other respectively. Just wasting juice otherwise unless you are growing a lot.
or cut the bullshit and run Ceramic Metal Halide bulbs through the whole grow and get the best of everything in one bulb. You won't regret it.
HPS is fine for vegetative growth and flowering as well. Many growers will often use HPS only for veg and flower. Problem with HPS is it allows the plants to stretch. Benefit of HPS is incresed lumens per watt and lower bulb temps. Metal Halide is pretty much only good for veg, although you "can" flower with them, it is not recommended. Problem with MH, Higher burning temps, not good for Flowering Alone, and lower lumens per watt vs HPS. Benefit of MH is compact bushy growth, and decreased distance between nodes. SO my conclusion to this subject is..... Using HPS along with MH during veg stage gets you incresed lumens over using 2 MH. Using 2 HPS during veg stage will give you increased distance between nodes. Using 2 MH would be "normal" in veg. Using HPS along with MH in the flower stage helps to keep growth compact and bushy but you could be getting more lumens and less heat in there with a 2HPS setup. I would use the HPS MH combo for veg but switch to 2 HPS for flower. However I would not consider this an advanced growing technique.
HPS puts out more lumens per watt. I wouldnt even buy MH were I you. also, note this equation 400w + 400w does NOT = 800w. its just 2 400w's from different angles. if you can go higher wattage, do it, thats the only regret with my setup.
Light Spectrum. \t \tThe average color temperature of the \tsun is 5800 Kelvin throughout the year. What we see on earth has \tbarely measurable spectrum differences between spring and fall. \t \t \tThe sun produces energy in pulses, \tlike a carrier wave. Let us consider the photosynthetically active \tportion of this pulse, from the lowest frequency--red (675 nm)--to \tthe highest frequency--blue (400 nm). (“nm” means “nanometer”. \tA lightwave that is one nanometer is one billionth of a meter in \tlength.) \t \t \t \tThis pulse is like a train, with the \tblue in front and the red in the rear. The Red light acts like an \tengine placed at the end of the train, pushing the orange, causing a \tchain reaction, the whole spectrum working together synergistically. \tThe best light for plant growth is full spectrum, like the sun, with \ta slight increase in red spectrum due to evolution and the fact that \tred travels through forest canopy better than blue. \t \t \t \tRed light is the most efficient \tmonochromatic spectrum for plant growth. However, all the colors \thave functions. If a person were especially good at hearing bass \tsound, that means the other pitches should be emphasized, so that \tone could hear the whole melody. For light to be efficient for plant \tgrowth, it must be full spectrum with close to equal linearity and \tamplitude through the production of 400-700 nm, with a slight bump \tin the red. \t \t \tThe blue spectrum has \tthe highest energy and shortest wavelength [see: Light Measurement \tHandbook (1997), by Alex Ryer, page 8]. \t \t \t \t \t \t \tBlue is in the front of \tthe light train, acting like a spearhead to penetrate the leaf, \tcarrying the other colors with it. The far blue range includes UV-B, \tsimilar to what is found at high altitudes, and increases the prized \tphenolic compounds. This increases the flavor of peppermint, \tlicorice, pepper, etc. \t \tConventional wisdom dictates that \tthe growth phase be illuminated by a quartz metal halide (for blue \tlight), the bloom phase by a high pressure sodium (for yellow/ \torange light). However, \ta full spectrum is needed for all phases for a variety of functions. \tBlue induces growth hormones and rooting, and reduces stem \telongation. Red induces flowering hormones, and provides energy for \tgrowth of flowers and leaves. Using only quartz halide during growth \tphase results in slow growth due to less red light. Using only HPS \tlight during flowering stage often causes leaf yellowing, due to \tlack of growth hormones; and tends to cause stem elongation. \t \t \t \tAn artificial light \twhich reproduces a red-enhanced full spectrum is the “Ceramic \tMetal Halide” or “High Pressure Metal Halide”. This has more \tblue than a metal halide with a conventional quartz arc tube, and \tmore red than an HPS, so it’s spectrum is optimum for all stages. \tThe Ceramic Metal Halide (CMH) features a ceramic arc tube like an \tHPS, and uses an HPS magnetic ballast. Philips has recently come out \twith a horizontal version of this bulb, resulting in longer bulb \tlife and 1000 lumens more compared to a vertical cmh bulb operating \thorizontally. Generally, horizontal works best. \t \t \t \tFor those limited to magnetic \tballasts, CMH is probably the best plant light available. For the \tLife Light electronic ballast, Life Lights also produces \tfull-spectrum pulse-start metal halide bulbs. These are more \tefficient than normal halides, with better spectrum. They are \tdesigned to accommodate the 100,000 pulse rate of the Life Light \telectronic ballast. These come in four spectrums: \t \t*6K for rooting and early veg \t*4K for general growth/bloom \t*3K for late bloom \t*10K for finishing (last 2 weeks) \tIf you can’t afford all four \tbulbs, the 4K is fine for all stages. \t \t \tThe CMH has a better spectrum and is \tmore efficient electrically than the retro-fit HPS that operates on \ta MH ballast. The retro-HPS is more expensive, lasts only half as \tlong, and has reduced output, compared to a regular HPS. Also the reason a HPS and MH together would be better the light train is crucial. Hope that info helps. In Hindsight I should have posted this earlier for all those gentlemen I was having a debate with in the thread we had running in general indoor growing. Mixed spectrum period is the only way to really get even close to emulating the sun's capabilities in a indoor environment.
why the change of heart on CMH only? the numbers are certainly there for CMH still to this day. just curious is all.
Its great for a small grow but these days I live in Nor Cal and grow inwhole rooms for myself and medical patients. Kind outgrew it mymn thats all I run 3 600s in my flowering now going up to 8 total. As far as I knoa they still only mak the philips mastercolor in 400. Too smallforme 600s or 1000s now.
FYI RichardDean-- Philips makes an 860w CMH bulb for use in 1000w mag ballasts. I called a Philips rep just to ask and he said some local electrical supply shops carry them. Last I checked they made it in vertical only. I'm waiting to see someone put that baby in a Luxor and fully flower a stretchy sativa strain. They don't market them for agriculture at all. Probably because they already have an expensive specialty agro line.
All of these responses are missing the key point. What area do you intend to cover? If it's only a few plants and both lights would shine on all the plants at once, then some sort of mixed spectrum is great. But if you are trying to cover a larger area, such that one light is covering roughly half and the other light the other half, then you are not getting mixed spectrum unless you continually rotate your plants (or your lights) so that each plant gets solid exposure to each, and not to just one for too long.
IMO and this is just me no data but MH is for quality and HPS is for quantity You wanna blow your mind put a UV bulb in there and flower trichomes go crazy check my thread Sent from iPhone 5