I have switched from CMH to HPS with about three-four weeks of flower left with no issues at all. However, I find these anecdotes fascinating. I bet there is some merit to this.
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FrameOMind
Member
I am going to do the same switch soon, so I hope I don't get the same results.
elMarcel, were you and your friend running the same strain? If you were, maybe that strain is sensitive to the change in blue spectrum or possibly the change in light intensity/heat.
elMarcel, were you and your friend running the same strain? If you were, maybe that strain is sensitive to the change in blue spectrum or possibly the change in light intensity/heat.
dude, there is no way you could say switching from cmh to hps is like bringing a plant from outdoors to indoor lighting. WAY different changes going on there.
The amount of UV emitted by the CMH is so negligable unless you have found some way to remove the protective glass around the bulb.
I'm sure there is a much better explanation for why your plants experienced stress.
The amount of UV emitted by the CMH is so negligable unless you have found some way to remove the protective glass around the bulb.
I'm sure there is a much better explanation for why your plants experienced stress.
Yes it is already well know and documented, some researchs about UV and dioecious strains like rape, show us that the amount of hermies plants increase a lot when the amount of UV brutally fall off.
My friend was running ECSD (dhk cut), Sweet Skunk (SOL cut), Bubba Kush (Katsu cut), Bubblegum (Slard cut), UK Cheese (Exodus cut), AK47 (Groovy cut), Roadkill Skunk (Braindead cut), some pure Nepalese, and a few others strains, and I was running Angel Heart from Shanti (Mango Haze X Afghan/Skunk), Jacks Cleaner 2 from Subcool/TGA, UK Cheese (Exodus cut), NYCD (bbm2 cut) and Sour Diesel (Riri cut).
Not all of the plants turn hermies, but our runs were all seeded after switching from CMH to HPS.
You can believe me or not, but the facts are there.
About the neons to complet spectrum of HPS, do you advice reptiles ones like Arcadia, or Purple ones ?
Best vibes to you.
Marcel
ps : sorry my english is not perfect, I am french
W
whiterasta
Very interesting Marcel. and I can see how the change @ the 3/4 week point could really stress a plant.Their are a number of nutritional/hormonal changes occuring at this point of flower.
Take one look at the spectrum of an HPS vs a CMH and it will show the plant has geared up to use all of the varieties and absorption spectra of all four major chlorophylls and carotenes and then has the source of those spectrum cut off. A shock to be sure and certainly enough to cause dimorphism. Plants can survive and grow under the limited specra of HPS but in doing so favor the red-orange absorbing chlorophyll for metabolism.
I would conclude that going from HPS to CMH would show a marked improvement in plant health and growth while the reverse would cause nutritional stress due to formerly active levels of the blue end being cut off and the plant then needing to regear to the limited red-orange of the HPS. Excellent report Marcel and further indication CMH is allowing the plant a more natural light than previous bulbs. I have gone from 10K blue aquarium bulbs to HPS and have never seen this happen but given the flat full spectrum of CMH I can really see how this can ocurr.
WR
Take one look at the spectrum of an HPS vs a CMH and it will show the plant has geared up to use all of the varieties and absorption spectra of all four major chlorophylls and carotenes and then has the source of those spectrum cut off. A shock to be sure and certainly enough to cause dimorphism. Plants can survive and grow under the limited specra of HPS but in doing so favor the red-orange absorbing chlorophyll for metabolism.
I would conclude that going from HPS to CMH would show a marked improvement in plant health and growth while the reverse would cause nutritional stress due to formerly active levels of the blue end being cut off and the plant then needing to regear to the limited red-orange of the HPS. Excellent report Marcel and further indication CMH is allowing the plant a more natural light than previous bulbs. I have gone from 10K blue aquarium bulbs to HPS and have never seen this happen but given the flat full spectrum of CMH I can really see how this can ocurr.
WR
Interesting observation. Last year I had 3 Northern Lights and 2 C4 x Black Russians all hermie around the 6th to 7th week of flower. I just kept plucking the nanners and the ones I missed never really propogated any seeds. They were vegged under a CMH for 5-6 weeks and flowered the full time under a HPS.
The year before that, nothing hermied.
I did the flip last week on this years run and I'm going CHM all the way.
The year before that, nothing hermied.
I did the flip last week on this years run and I'm going CHM all the way.
W
whatissixbynine
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binaryfission
Member
so if it is the UV fall off that causes the stress, then it seems like you need the reptile bulb. also i think heat might have something to do with it? do you have any records of your temps?
also, why is everyone talking about the spectrum differences when the issue seems to be UV?
UV light is part of the color spectrum.
hello IC forums!(first post ever)
I am really interested in growing with a CMH bulb and have some leftover HPS ballasts from a grow long gone and was wondering if these specs are too much to handle for the 400w CMH bulb. considering I dont know any electronic specifications any help is appreciated
heres my ballast specs
http://ultballastspecs.unvlt.com/pdf/high_intensity_discharge/S1000ML5AC5M.pdf
I am really interested in growing with a CMH bulb and have some leftover HPS ballasts from a grow long gone and was wondering if these specs are too much to handle for the 400w CMH bulb. considering I dont know any electronic specifications any help is appreciated
heres my ballast specs
http://ultballastspecs.unvlt.com/pdf/high_intensity_discharge/S1000ML5AC5M.pdf
HillBillMt
Member
we just outfitted a room here for $40 a bulb purchased localy, at six of them we saved a bundle...
dwarfganja
Member
Yes that ballast will not work.hello IC forums!(first post ever)
I am really interested in growing with a CMH bulb and have some leftover HPS ballasts from a grow long gone and was wondering if these specs are too much to handle for the 400w CMH bulb. considering I dont know any electronic specifications any help is appreciated
heres my ballast specs
http://ultballastspecs.unvlt.com/pdf/high_intensity_discharge/S1000ML5AC5M.pdf
You need a 400W HPS mag ballast
hello IC forums!(first post ever)
I am really interested in growing with a CMH bulb and have some leftover HPS ballasts from a grow long gone and was wondering if these specs are too much to handle for the 400w CMH bulb. considering I dont know any electronic specifications any help is appreciated
heres my ballast specs
http://ultballastspecs.unvlt.com/pdf/high_intensity_discharge/S1000ML5AC5M.pdf
Welcome to IC!
Short of buying whole new ballasts (lol...or growing outside), HPS will still get you good results. Although I would ask, do you have access to same or smaller size MH ballasts? I really like the mixed spectrum the CMH provides and it is that same mixed spectrum most strive for with a MH/HPS mix. A lot of the old timers advocated such a mix for good reason!
My last bloom under CMH 400W was in summer, with very high temps, I had > 30°C in the box, and zero hermies.
My first bloom under HPS 600W was a few weeks ago, in hard winter, temps were very low (15 -> 25°c) in the box, and I had a lot of hermies.
So I do not think heat was the stress !
maybe low lights off temps caused you to have that happen
but you say yourself that temps were higher after the switch. a stressor aside from lack of uv
