well there is alot of talk about it over at icmag thought I would start a thread about it here since it does seem to be such a new topic. advanced tech lighting has the 400watt Retro White Ceramic Metal Halide bulb that runs on your standard magnet and core 400 watt hps ballast which are cheap and common. Make sure you get the horizontal operating bulb. The spectrum you get from a CMH bulb in comparison to a hps bulb or a mh for that matter is so much better hands down and that is what really convinced me. Here is the actual site if you care to take a closer look and why wouldn't you with specs like that. Lumens are not what grow good ganja it is the spectrums that it recieves. http://advancedtechlighting.com
looks like it's peak spectrum (or however you want to put it) is green? thats the only color that doesn't affect plant growth at all...
but the whole other band is pretty much at an even distribution. THese lights can be run very close to the plants as well as compared to an HPS or MH which also makes difference. From this at 11-14-07 to this at 12-15-07 Looks to me like the results speak for themselves, this is not my grow but someone else on icmag that is using 2 400watt CMH bulbs
I just got a 400Watt CMH. These things work. You'll see them replacing HPS/MH setups. CMH is essentiall both combined in one lamp. It was done by phillips in 1994.
so off that website. i should buy the CMH HPS retro white? since its still a hps, will it need a cooling system?
That is an impressive light. On the same site, I found CFLs that look like they would be great for growing too: Note the peak output ranges, 460 nanometer and 650 nanometer correspond to the wavelengths that plants use for photosynthesis. PURple ~ Bio Tropic 25000K Color appearance to human eye Pink. Nm Peak's 460nm & 650nm
i read through like 20 pages of the icmag post about them. They're suposed to be a lot cooler than HPS but still would need cooling. From what I read they disapate heat verticly so you can get the lights closer to the plants (1"-6" even from what I read) and are warm to the touch. but really all the information is there so just read
HPS has higher lumens output, which is all that matters. Also I dont know if it is a conversion bulb, but a 400w MH conv bulb runs a hell of a lot hotter than an HPS.
Lumens is how much light they have available to them and the spectrum is dealing with how well they will be able to use it at any given point in their life. To say that only one matters is crazy imo. These bulbs seem to be well rounded in general, and would most likely be a better bet for anyone using either mh or hps throughout the whole grow. Not sure if its better than mh + hps switch though, wish those pictures worked for some reason i cant see them. I want one of these.
HPS has higher lumen output and the spectrum is fine for cannabis. Why waste your money on a hotter, less efficient lamp? By your thinking your could just use a couple of full spectrum fluoros but the reality is that big orange light (HPS) will give you a MUCH bigger yield.
lumens really doesn't have as much to do with plant growth as most think my friends. The CMH puts out more red than an HPS, more blue than a MH and it also gives off a decent amount of UV(for those that don't know the presence of UVB is directly related to THC production, so yeah important yet absent from most indoor gardens) that is pretty much nonexistant on mh and hps bulbs of any brand. THe quality of something under CMH is much better than HPS and the yield is just as good or better. It runs a hell of alot cooler than the mh or hps and the plants love it for sure.
The bulb specs claim to disperse heat vertically away from the bulb, therefore making it cooler than standard hps bulbs. dont know if its true but if you're using a mh or hps throughout the entire grow it would undeniably be better to have full spectrum. Use an HPS in veg and it in no way absolutely positively CANNOT compare to growth you would see with a mh in veg period. It's the spectrum.
I've vegged my mums with HPS for about 8 years. Very happy with the results, thanks. I recently used a MH conversion lamp on my mums for about a month. The MH produced shorter, more dense growth than the HPS, as one might expect. This would be desirable in the case where one is vegging plants before they are flowered. However, given I am running a SoG where there is zero veg time given to clones between setting root and being chucked in to flower, I prefer to cut tall clones- about 9". The elongation produced by HPS in veg is in my case desirable. See the links in my sig for details. I switched back to HPS and the MH conversion lamp sits on the shelf. The CMH looks interesting but it does produce light in spectral segments that the plant can't use or won't use in just veg or flower. That's reflected in the lower lumens/watt output of CMH vs HPS (40K lumens for a 400CMH vs 56K lumens for a 400HPS). HPS produces higher luminous output by not faithfully reproducing a full spectrum. MH is limited spectrally as well but produces a more blue biased overall spectrum. The wavelengths that produce greatest photosynthetic activity in flowering cannabis plants are well known and HPS suits them rather closely, given cannabis in flower wants a red-orange spectrum to mimic the sunlight of late autumn. If I was running an op where I was vegging plants that would later be flowered, I'd probably have a try with the CMH.
to me it looks like that peak is closer to yellow (like HPS) than to green and it's only one peak. the spectrum is very broad with the entire light band showing a minimum of 20% relative output remember cannabis evolved over time under the broad spectrum of sunlight. to be true to her we might think about giving her what she's always gotten or at least as close as possible. it's not always about us...............
Wow, I never knew that photosynthesis occurred at such opposite ends of the spectrum? Is this accurate? I wonder if anyone ever tried growing with actinics; they're down in the 400-ish nm range..
technically, it is PAR (photo active radiation) that makes the difference. 20000 lumen in the 450 - 650 nm range will grow spindly, anemic looking plants. The lamp in question will work but IMO it wastes a lot of energy making light that doesn't help the plant grow. Humans are more attuned to light in the green range of the spectrum, that's why this lamp seems much brighter than a lamp that produces light in the red or the blue bands.
im currently using 1 400w hps and 1 400w cmh and the plants are loving such a full spectrum of light. Both bulbs are in aircooled hoods and there isnt much of a difference between them in temp., they are both cool.