Using an HPS bulb for vegetative growth.

Ghettogrower187

Well-Known Member
Funny I've just been down to the grow shop today to get a new hps bulb to veg with...I switched back to mh for veg about 3 months ago and noticed the growth is a lot slower using metal halide idk why but it just is.....hps all the way ftw :)
 

kmog33

Well-Known Member
Funny I've just been down to the grow shop today to get a new hps bulb to veg with...I switched back to mh for veg about 3 months ago and noticed the growth is a lot slower using metal halide idk why but it just is.....hps all the way ftw :)
Mh puts out less light at the same wattage as hps. Also under the blues in mh the plants do not stretch as muh so they have denser growth but tend to stay shorter while in veg under my because they stay compact. The reds in hps cause the internodes to stretch and elongate more than mh, causing the perception of faster growth.


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ttystikk

Well-Known Member
Funny I've just been down to the grow shop today to get a new hps bulb to veg with...I switched back to mh for veg about 3 months ago and noticed the growth is a lot slower using metal halide idk why but it just is.....hps all the way ftw :)
Because MH SUCKS, bro lol. It's a shit tech that needs to be outlawed like incandescent lighting.

Use 315W CMH lighting to get both spectrum and performance.
 

ttystikk

Well-Known Member
Mh puts out less light at the same wattage as hps. Also under the blues in mh the plants do not stretch as muh so they have denser growth but tend to stay shorter while in veg under my because they stay compact. The reds in hps cause the internodes to stretch and elongate more than mh, causing the perception of faster growth.


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When I need plant height rather than dense growth it's not about 'the appearance' of growth, it's the real thing!
 

kmog33

Well-Known Member
Aye I know what u mean but honestly I think it's best to veg hps I get u on the shorter internodes but it's not that much at all if anything really....hps for the win I say
If you match actual light output there is a huge difference. the cmh bulb are on par with se hps efficiency wise, so if you go watt for watt with se hps, cmh should beat it and be noticeable in doing it.


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kmog33

Well-Known Member
When I need plant height rather than dense growth it's not about 'the appearance' of growth, it's the real thing!
Height is the appearance of growth vs stacking twice as much in the same height is actually more growth and will produce more when you add the Reds in flower. If you veg an mh plant the same height you would an hps, it will produce more(given the same strain an environment).


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ttystikk

Well-Known Member
If you match actual light output there is a huge difference. the cmh bulb are on par with se hps efficiency wise, so if you go watt for watt with se hps, cmh should beat it and be noticeable in doing it.


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315W CMH lamps are as efficient as DE, right there with the best in the HID lighting business. Both are now handily eclipsed by COB LED tech, and the price premium is disappearing rapidly.
 

ttystikk

Well-Known Member
Great that you vegged with a hps but have you actually got any veg pics cause all these are flowering and its not giving a good representation of the veg period for hps unless your showing that.
Plants grow fine, just longer internodal spacing.
 

kmog33

Well-Known Member
315W CMH lamps are as efficient as DE, right there with the best in the HID lighting business. Both are now handily eclipsed by COB LED tech, and the price premium is disappearing rapidly.
Yeah I didn't speak with exact % because I don't keep up with hid anymore. But that just furthers my point of they work better for veg than hps at the same output. You would have shorter, denser internodes even if the plant was shorter and they should produce more in flower given you flower both under hps. Spectrum X light intensity = plant growth. Most growers use whatever is available to them to get both, but generally you sacrifice one for the other. Cobs are definitely changing the game, but the price of the efficiency upgrade isn't enough yet to get a lot hid growers to swap spectrum for the shear intensity hids put out. It'll happen at somepoint but not quite there yet. And companies like gavita are really holding on to the tech and trying to mod them to keep up with led, but it seems like a losing battle as the efficiency of LEDs continues to dramatically increase and the spectrum choice is hard to beat.


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ttystikk

Well-Known Member
Height is the appearance of growth vs stacking twice as much in the same height is actually more growth and will produce more when you add the Reds in flower. If you veg an mh plant the same height you would an hps, it will produce more(given the same strain an environment).


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I'm growing vertically. I don't need tight internodal spacing for much/most of their veg cycle. I'm after height, and HPS drelivers REAL, measurable growth of the kind I actually need.

It isn't until near the end of veg that I need them to stack nodes.

You'very just run afoul of the limits of your perspective; not everyone grows the same way or has the same needs as you or your garden does.
 

bravedave

Well-Known Member
I started with MH all the way because the guy who helped me get going did. After being on RIU for awhile, the leading opinions seemed to be MH in veg and HPS in fiower...so on grow 4, I tried that. On day 50 of flower, I switched back to MH because I had noticably less frost than my previous 3 grows. (Same strains, similar conditions). Did increase my yield but every grow I have done that. One joy of being a nube. Grow 5, I did go back somewhat reluctantly to the HPS for flower, but added a 4' 4bulb t5 and loaded it with blues. The frost now matched my MH grow and I yeilded "about a pound" (+4) with 6 plants in 3.5 months. This grow I am going back to my MH all the way beginnings but still adding the T5 at flower.
Bottom line is if you restrict yourself to HPS, you may be missing out on some quality. UV is beneficial.
 

kmog33

Well-Known Member
I'm growing vertically. I don't need right internodal spacing for much/most of their veg cycle. I'm after height, and HPS delivers. That's REAL growth of the kind I actually need.

It isn't until near the end of veg that I need them to stack nodes.

You'very just run afoul of the limits of your perspective; not everyone grows the same way or has the same needs as you or your garden does.
While I totally get your point and growing for your space is definitely what you should be doing. The science is a totally different story. Even running vert, if you had twice as many nodes in The same amount of height, you would still yield more. Utilizing your space to its max efficiency is what we all aim to do. No need to get upset. Just stating how the science behind plant growth/hormones works during veg with spectrum. You're using cobs yeah? What is the reason people are using cobs if they don't produce more watt for watt than hid? Every grower want the most out of their space for the least amount of energy. Efficiency and spectrum are the keys to doing this. You can argue up and down all day about whether hps works better for your setup, which may be true. But I only stated that mh in veg produces more growth than hps when light output is matched. It is science, having to do with spectrum/triggering growth hormones, not anecdotal evidence as your vert setup is.


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ttystikk

Well-Known Member
While I totally get your point and growing for your space is definitely what you should be doing. The science is a totally different story. Even running vert, if you had twice as many nodes in The same amount of height, you would still yield more. Utilizing your space to its max efficiency is what we all aim to do. No need to get upset. Just stating how the science behind plant growth/hormones works during veg with spectrum. You're using cobs yeah? What is the reason people are using cobs if they don't produce more watt for watt than hid? Every grower want the most out of their space for the least amount of energy. Efficiency and spectrum are the keys to doing this. You can argue up and down all day about whether hps works better for your setup, which may be true. But I only stated that mh in veg produces more growth than hps when light output is matched. It is science, having to do with spectrum/triggering growth hormones, not anecdotal evidence as your vert setup is.


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I'm getting frustrated with you because you keep not citing papers but saying 'science says' and I'm calling your bullshit.

If carbon yield was my goal, that would be a valid yardstick. The problem is that it's about as valid a gauge of my desired performance parameters as the color of a car is a gauge of its top speed.

I know exactly what I'm doing with node spacing and I'm fully aware that most of those nodes grown in early through mid veg are removed as larf and are therefore useless and counterproductive to me.

There's no science that's going to convince me that growing shit I don't need leads to better yields, and you haven't cited any in any case. Therefore, this is a failure of your perspective, not mine.
 

kmog33

Well-Known Member
I'm getting frustrated with you because you keep not citing papers but saying 'science says' and I'm calling your bullshit.

If carbon yield was my goal, that would be a valid yardstick. The problem is that it's about as valid a gauge of my desired performance parameters as the color of a car is a gauge of its top speed.

I know exactly what I'm doing with node spacing and I'm fully aware that most of those nodes grown in early through mid veg are removed as larf and are therefore useless and counterproductive to me.

There's no science that's going to convince me that growing shit I don't need leads to better yields, and you haven't cited any in any case. Therefore, this is a failure of your perspective, not mine.
You can be as frustrated as you want. I didn't cite anything because I was pretty sure it was common knowledge. The entire grow lighting industry has been working on/with spectrum customization for flower vs veg forever. To mimic natural sunlight and the beneficial hormones it produces in your plants.

http://greenbookpages.com/blog/201690/high-pressure-sodium-vs-metal-halide/
http://ledgrowlightsexpert.com/led-grow-lights-guide/
http://ledgrowlightsexpert.com/led-grow-lights-guide/
http://www.ext.colostate.edu/mg/Gardennotes/142.html
http://www.cannabis.info/us/abc/30003816-dont-sweat-the-stretch
https://www.boundless.com/biology/textbooks/boundless-biology-textbook/plant-form-and-physiology-30/plant-sensory-systems-and-responses-184/blue-light-response-702-11927/
https://cnx.org/contents/xjt_KBai@6/Plant-Sensory-Systems-and-Resp


"The Blue Light Responses - Phototropism—the directional bending of a plant toward or away from a light source—is a response to blue wavelengths of light. Positive phototropism is growth towards a light source (Figure), while negative phototropism (also called skototropism) is growth away from light." - also may help in your vert setup as your are trying to get them to grow towards the lights, not up yeah?


"Now, horticulturists can manipulate plants to increase leaf, flower, or fruit production by understanding how environmental factors affect plant growth and development. Greenhouse management is an essential component of a horticulturist’s education. To lengthen the night, plants are covered with a blackout shade cloth. Long-day plants are irradiated with red light in winter to promote early flowering. For example, fluorescent (cool white) light high in blue wavelengths encourages leafy growth and is excellent for starting seedlings. Incandescent lamps (standard light bulbs) are rich in red light, and promote flowering in some plants. The timing of fruit ripening can be increased or delayed by applying plant hormones. Recently, considerable progress has been made in the development of plant breeds that are suited to different climates and resistant to pests and transportation damage. Both crop yield and quality have increased as a result of practical applications of the knowledge of plant responses to external stimuli and hormones."

"So, to prevent excessive stretching in the first place, we need to know what causes it. Disregarding genetic factors (some strains are just naturally stretchy), the two main causes are light and temperature. - See more at: http://www.cannabis.info/us/abc/30003816-dont-sweat-the-stretch#sthash.BxXIee9R.dpuf"

"Therefore, the chemical signal from the sunlight, which is blue wavelengths of light, was a growth stimulant; the phototropic response involved faster cell elongation on the shaded side than on the illuminated side, causing the plant to bend. We now know that as light passes through a plant stem, it is diffracted and generates phototropin activation across the stem. Source: Boundless. “Blue Light Response.” Boundless Biology. Boundless, 08 Jan. 2016. Retrieved 01 Mar. 2016 from https://www.boundless.com/biology/textbooks/boundless-biology-textbook/plant-form-and-physiology-30/plant-sensory-systems-and-responses-184/blue-light-response-702-11927/"
 

kmog33

Well-Known Member
As i stated before efficiency/intensity trumps spectrum, but science backs my perspective...I didn't realize we were going to reach this far into anecdotal vs scientific evidence.
 

Lpindicaman

Well-Known Member
So, I know that the general consensus is that you should use an MH bulb for vegetative growth but I started doing some research about using an HPS bulb for vegetative growth out of curiosity and came across some interesting things. The following was taken from Ed Rosenthal's "Marijuana Grower's Handbook":

MH lamps are the type of lamp used outdoors to illuminate sports events because they emit a white light. They were originally promoted as the light to use during the vegetative stage of plant growth, before the plants are forced to flower. But now it is generally recognized that plants grow as well vegetatively under HPS lamps as under MH, so they are not used that much because they emit less total light than HPS lamps and produce lower yields.

I found that to be very interesting. I also came across the following article for those who interested. http://www.hightimes.com/read/grow-hack-does-switching-metal-halides-hps-flowering-work. I don't know if hightimes has a bad reputation for poor article validity but there is any validity to it then I think there's enough information here for me to start being interested in this. I think Ed Rosenthal's word has more than enough merit I'm in the middle of my first grow ever and I've always been one willing to try new things. I have a couple of extra HPS bulbs laying around waiting for when it's time to flower. I'm thinking of giving this a shot. What do you guys think?
 

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