HPS only or HPS and MH

Mr.bagseed

Well-Known Member
I guess if no one has ever done this experiment (growing with HPS, then MH, then one for veg and another for flower, and then a mix), I will end up having to do it myself. I am fairly sure someone, somewhere has done this type of experiment. I'm fairly positive as large as this site is, someone on it has already done the experiment, or at least a majority of it. So, I'll keep bumping this up in the hopes they see it and answer my question.
...youre complicating things.
 

Countryfarmer

Active Member
woodsmaneh! is giving you good info!

Though I respect ed, I don't really agree with his conclusion on this one. Photosynthesis peaks at several wavelengths, and though you want to cater to chlorophyll A more, it still peaks at similar ends of the spectrum, and I am a believer in giving a wider spectrum opposed to a more narrow targeted spectrum (though I do believe in going for peaks around where chlorophyll peaks). The red spectrum has been shown to be slightly more efficient at producing sugars, but it's actually a minor difference in everything I have read. I still think variety is the spice of life :)
Appreciate the input, but are you saying you "believe" that both are needed during flowering, or have you grown with different lights and have determined that both are needed through your own experimentation.

Not trying to be difficult here, but while I am relatively new to growing, and will be brand new to indoor growing as soon as I complete my room, I do know the nature of people. We tend to fall in love with a solution for various reasons and then stick with it. Most of us are creatures of habit.

What I am requesting here is if someone has already played around with their lighting, tried Ed's way, Jorge's way and the combination of both types of lighting throughout and determined in that manner what has been best for them. I know that I can get a crop using any of the above. Like I said, I know I could fill my room with enough incandescents if I wanted to and get a grow (although that would be really, really inefficient).

So, no disrespect to anyone who has their favorite method, but I really want to hear from someone who has tried growing with various combinations of HPS and MH and what they determined was best. I'll probably perform that same experimentation myself over at least three different grows, but I am just looking for some input from someone who already has done so.

Thanks again to those who have offered their input though.
 
I guess if no one has ever done this experiment (growing with HPS, then MH, then one for veg and another for flower, and then a mix), I will end up having to do it myself. I am fairly sure someone, somewhere has done this type of experiment. I'm fairly positive as large as this site is, someone on it has already done the experiment, or at least a majority of it. So, I'll keep bumping this up in the hopes they see it and answer my question.
You are just going to get a bunch of different opinions.Try it for yourself and you will know what you want.
Me personally i veg with a 150 hps and flower with a 400 hps.So yeah i use hps all thru.Ive used mh and hps and i really dont see much differnce in yeild if any difference.Just plants grown under hps will be alot taller,node spaced out more than if you would veg with a mh.
Never used mh and hps during flowering at the same time but if i want blue light in there i would just add cfls.I do feel like mh is a waste of electricity.I rather use t5s or my hps.
 

k.o

Member
It's as simple as this, if you have the money do MH for veg and HPS for flowering, else just do HPS the whole cycle. Either will produce high quality results, the reason yield will be slightly better with a MH in veg is for the more of a blue spectrum they give off which is suitable for strong and healthy foliage growth during veg.
 

k.o

Member
You are just going to get a bunch of different opinions.Try it for yourself and you will know what you want.
Me personally i veg with a 150 hps and flower with a 400 hps.So yeah i use hps all thru.Ive used mh and hps and i really dont see much differnce in yeild if any difference.Just plants grown under hps will be alot taller,node spaced out more than if you would veg with a mh.
Never used mh and hps during flowering at the same time but if i want blue light in there i would just add cfls.I do feel like mh is a waste of electricity.I rather use t5s or my hps.
Out of interest why are you downgrading your wattage during veg? you are only decreasing your yield, why not 400 hps whole cycle? I can understand maybe 150 hps for the first week or so but not the whole veg cycle.
 
I have a veg chamber and a flower chamber.The 400 is used to flower the 150 is used to veg.
I like doing perpetual grows.I hate starting back from scratch when im done.Dont get me wrong I use my 400 from time to time when i dont have nothing in the flower room but now i do so i will use the 150 to veg.
 

Countryfarmer

Active Member
I use mh and switch to hps 2 wks after i go 12/12. My plants stretched to much with just hps.
Thanks. This is the kind of information I have been looking for, someone who has used HPS only as well as MH and HPS. Southern Homegrower, except for the stretching of the plants under HPS only, did you notice any difference in the quantity/quality of harvest compared to when you went MH for veg and the beginnings of flowering?
 

Countryfarmer

Active Member
country farmer what is your opinion on the Hybrid lights? That has both in one...
While I know the hybrid lights give the blue spectrum of the MH as well as the red of the HPS, I have yet to find anywhere where someone has done an experiment comparing results to HPS only and other combinations. I think the hybrids would do a better job of coverage than changing the ratios of lighting, simply because they are side by side and so you would get both bandwidths hitting the same area, but that is just my thought on the matter and I have nothing to back it up with.

I guess the reason I keep coming back to this is because of Rosenthal's statement concerning MH lights and the fact that MH lights are more wasteful of lumens/PAR than HPS. I really do not care if a plant stretches as I plan on growing SCroG style anyway, so a stretched plant is just a plant that has to be tucked under the screen a little more often until it flowers.

If the end result in quality/quantity is not any different, then I will probably stick with HPS only as it would be easier to control room temperatures using HPS than MH. But, if mixing the lights, or using one at one stage of development and another at another stage of development, leads to either a definable increase in production or a better smoking product (I personally doubt this latter point as I think smokeability is tied into the curing process, not the growing) ... well I would like to know that as obviously we all want our production to be the best it can be.

I am going to continue to look around the internet for anyone who maybe has done the light experimentation I am talking about (I know someone has) and see what they have to say. Even if I find it, at this point I plan on doing my own level of experimentation, but I would like someone else's results to compare mine to.
 

Dwezelitsame

Well-Known Member
i use both with a uvb for flower time

im in a small tent i use soil and organics i run a 250w hps and a 250w mh rotate pots every week to benefit from both

every couple or three days i spin pots in place at flower time i put uvb on one hour a day as far away as i can from plants and stick to my spin rotate schedule

this works fine for me

good luck
1Luv
 

gobbly

Well-Known Member
Appreciate the input, but are you saying you "believe" that both are needed during flowering, or have you grown with different lights and have determined that both are needed through your own experimentation.
I do not believe that both are needed, there are many many examples of people using all HPS, all MH, all CFL, all T5, all LED, etc, and getting great results (and examples of people using them and not having great results also). There are so many variables that without setting up a proper experiment with controls it's difficult to say one way or the other. Personally I have grown with MH, HPS, and T5's. I currently flower with a MH and HPS and I get better results than when I used the MH or HPS alone (keeping in mind it has been several years since I used an HPS alone), however it's twice as much light as when I had either alone, so really hard to tell that it was a difference made by spectrum (actually, impossible to say if the spectrum had anything to do with it). I tried to phrase my post as my opinion, and I actually think your whole question is more a matter of opinion and individual experience than a hard rule (based on the research I have done, which is conflicting).

Not trying to be difficult here, but while I am relatively new to growing, and will be brand new to indoor growing as soon as I complete my room, I do know the nature of people. We tend to fall in love with a solution for various reasons and then stick with it. Most of us are creatures of habit.
There are a lot of things in this hobby that aren't black and white. There are so many variables. I get what you're saying, but I'm not really trying to endorse one method or another, more just give you an alternative viewpoint. I am not the expert source that Rosenthal is (not saying anything about my knowledge, but ed has written many books, coauthored one with my favorite grow author, as well as written for high times, no way I can match his resume :D), and it's up to you what you decide to take, and what you decide to leave. I was more trying to say that people do flower with a HPS/MH mix, and that there are compelling reasons to go either way if you purely are looking at the science.

What I am requesting here is if someone has already played around with their lighting, tried Ed's way, Jorge's way and the combination of both types of lighting throughout and determined in that manner what has been best for them. I know that I can get a crop using any of the above. Like I said, I know I could fill my room with enough incandescents if I wanted to and get a grow (although that would be really, really inefficient).
The way I like to look at a lot of these questions is on how much benefit things might have. From my experience and looking at many other growers, it just doesn't seem like these spectral changes are making a dramatic difference (assuming they are providing one of the chlorophyll peaks with sufficient intensity). Not to say there isn't a difference, but for instance, the intensity of the light has always seemed to me a much much larger difference in the end product than which light I chose to use. The type of light (and therefore spectrum) have not seemed to make as dramatic of a difference to me (as long as you are covering a photosynthetic peak), in fact, oftentimes if I don't know which light is being used (say in pictures), I can't really tell what type of light was being used.

So, no disrespect to anyone who has their favorite method, but I really want to hear from someone who has tried growing with various combinations of HPS and MH and what they determined was best. I'll probably perform that same experimentation myself over at least three different grows, but I am just looking for some input from someone who already has done so.
None taken at all :) We all have our opinions, some based more on experience and/or science, some less, but its still all just our experiences. As I said, I have grown with both, and other than it being twice the wattage when mixed, I didn't feel like it was a dramatic difference. Then again, hard to tell when I mixed because it's twice the light output, and you bet that I saw the results of that :D. Anyway, GL, hope you come to a conclusion you are happy with :)
 

Dwezelitsame

Well-Known Member
i use them together but if you want to be max effiency its mh in beginning two weeks or so to reduce stretch

then hps in middle to get nice hard buds

then hps the last two weeks to max on flower fattening

but i just rotate under both through entire flower spinning pots along the way

and thats grow experience

good luck all
 

southern homegrower

Well-Known Member
Thanks. This is the kind of information I have been looking for, someone who has used HPS only as well as MH and HPS. Southern Homegrower, except for the stretching of the plants under HPS only, did you notice any difference in the quantity/quality of harvest compared to when you went MH for veg and the beginnings of flowering?
Like someone here said there are a lot of differences from one grow room to another . One persons grow room may have low rh or high rh, temps may go up and down more drastic. My grow space is 7 ft tall and with my aero tubs and lights only left me about3 1/2 to 4 foot of plant height. So when used hps the hole way through plants got to tall and the light and heat from being so close to the plant hurt my yield . If you are thinking of using ceramic bulbs there is a person named riddleme that has great grows and he is an ace for answering ? He knows his shit. I have been hearing good things about ceramic bulbs from people who know what they are doing so i beleave what they say but i have not tried them
 

Countryfarmer

Active Member
No. I may use CMH in the future, but I am already invested in digital ballasts, so I will be doing MH and/or HPS grows. I have read Riddleme's journals in using CMH and admit it has peaked my interest in that technology. But I probably will not even attempt a CMH grow until I move from this location to another.

I understand that there are a lot of variables, even within the same grow room from one grow to another, but I was looking for "the voice of experience" who has experimented with the different light set ups. As of right now I am planning on doing an HPS only grow for my first run, and then experimenting with adding MH to the mix. When I started this thread I was hoping to get data from someone who has done the various combinations I have already listed along with their take on how it worked for them in order for me to have a comparison set.
 
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