Metal Halide VS High Pressure Sodium FLOWERING

I have searched upon this topic.

I see conflicting results.

Some things that are the same are that,

MH: UVB helps produce slightly higher concentrations of THC and resin

HPS: Buds are more stretchy, but better in some ways
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But, I have yet to find any threads with documented grows, maybe clones, showing the comparison between MH and HPS Flowering cycles.

Anyone with photos?

Sorry mate, no pics, but I will say this:
The best lights for vegging and flowering are horticultural HPS bulbs.
The UVB light produced by MH is very low. I always buy a special 10% UVB light from pet stores in order to get that really sugary trichome production.

HPS is the best for flowering
MH is best for vegging
Its because of their spectrums
if you add the 2 then its even better, not saying mh wont grow good bud its just not as ideal as hps. MH is best for veg

i do fluoros for starting
mh to veg
hps for flower.
but even tho ive never used them, from what i hear i would have to agree with doc cannabis. i will try those hort. bulbs someday.

I use both... I use the Solarmax1 bulb which is a 400mh & a 600hps in the same bulb..... expensive, but the results are uncomparable... you need a 1000watt hps ballast to run it.
Using both spectrums, gives some unreal buds

I've done both, this grow I switched back to HPS because I feel that the MH takes too long to finish. I like the MH, it helps keep the plants compact and has a better coloUr rendering index for working in the garden. The buds were less fluffy, more solid but smaller than HPS buds. A little less weight/volume at harvest.

I haven't measured it but I think the plants take a bit longer to switch from veg to flower with MH, the HPS 2100K coloUr tells the plant that summer is over. A 3000K to 4000K MH may have summer coloUr, one less thing to entice the plant to switch to flower. Be sure to use a full spectrum bulb like the Sunmaster Warm Deluxe. I've got a Hortilux Daytime MH, around 5000K, it's suppose to be one of the closest bulbs to real summer time daylight. I've had it for 2 years and have yet to work it into the garden, should be interesting buds.

I found everything else pretty much the same.

I've chatted with several growers who use MH, even a commercial grower who uses HPS for business and MH for personal stash. They say there is no difference in potency.

As for UVb I just started using the same Lizard Lights as Doc Cannabis today.

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why is this crap in advanced growing ?

DaveTheNewbie said:

why is this crap in advanced growing ?

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Quiet noob.

Because this has not been fully Documented yet, I have not seen anyone posting results where a MH versus HPS were grown side-by-side.

Until then, I think both have unconfirmed truth's and lies.

OMG, I cannot believe what I'm reading here..
Look, MH's are great for VEGitive growth because of the Blue~White Spectrum, which Promotes Growth...
HPS which is on the more yellow/red/Orange ends of the Light Spectrum are more condusive for Flowering....
There is 'NO" unconfirmed BS, whether MH vs. HPS is better for flowering vice versa..
I've seen Many examples side by side, and by My own experience..
HPS is better.. Think, your in effect fooling the plant, manipulating photo-period in the Light HOURS, plus using the red/yellow ends of the Light spectrum, the plant "senses" that "Fall" is approaching, thus produces flowers,, ie: buds...
think about it...

dursky said:

I use both... I use the Solarmax1 bulb which is a 400mh & a 600hps in the same bulb..... expensive, but the results are uncomparable... you need a 1000watt hps ballast to run it.
Using both spectrums, gives some unreal buds

Click to expand...

Would this work on a digital/electronic ballast? It runs both HPS and MH.. I wonder.

crossthread said:

OMG, I cannot believe what I'm reading here..
Look, MH's are great for VEGitive growth because of the Blue~White Spectrum, which Promotes Growth...
HPS which is on the more yellow/red/Orange ends of the Light Spectrum are more condusive for Flowering....
There is 'NO" unconfirmed BS, whether MH vs. HPS is better for flowering vice versa..
I've seen Many examples side by side, and by My own experience..
HPS is better.. Think, your in effect fooling the plant, manipulating photo-period in the Light HOURS, plus using the red/yellow ends of the Light spectrum, the plant "senses" that "Fall" is approaching, thus produces flowers,, ie: buds...
think about it...

Click to expand...

Says the guy with 4 posts.

whoreable said:

Says the guy with 4 posts.

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So you mean that the more posts you have the more you know?
That's bullshit. He still gave the most correct answer and may have been growing for eons for all we know.
I see people on here with thousands of posts giving incorrect info all the time,
and sometimes it's laughable that people here have fights and arguments because they insist they know everything as they have more posts.
Chill, learn and share.

and learn to use the search button before posting such a simple and common question that has been addressed so many times before

Now, now, let's not turn this into one of "those" threads... True, the number of posts is no real indicator of someones experience. Also, this is not really such a simple topic. Here's my opinion on MH and HPS:

I personally believe that HPS works just as good for vegging as a MH or even better. I believe this because if you take a look at a normal MH spectrum (http://www.progressivegardens.com/growers_guide/EYE_MH_conversion_graph.gif), you will notice that it contains alot of green light, which is useless to plants. On the other hand it contains a large amount of blue. Plants are not as responsive to blue as they are to yellow and red. Blue light is only used as a guide for the plant for it to grow towards the light (in nature, plants guide themselves by means of the blue sky...). So practically, the blue spectrum will only add to the plant's height and vertical growth, not to it's bud production.
If you take a look at a HPS spectrum (http://www.progressivegardens.com/growers_guide/EYE_HPS_conversion_graph.gif) you will notice alot more yellow and red, the most useful types of light for a plant, and less green and blue... Practically, a higher percentage of light can be absorbed and used towards bud production from a HPS than a MH.

From my personal experience, MH will make a plant strech more towards the bulb, HPS keeing it bushy and compact. MH will not produce large buds, but will assure greater bud space due to the streching. HPS will make buds large, maybe not as compact, but will not assure greater bud sites.

SO I swutched to horticultural HPS... these are bulbs with added blue spectrum. I noticed that plants grow as high as with a MH, providing more bud sites than with a regular HPS, but will produce better flowers than with an MH...

All of this is of course just my experience...

"From my personal experience, MH will make a plant strech more towards the bulb, HPS keeing it bushy and compact."

Interesting. I've found the opposite but I have had incredible stretch with DP Blueberry and Strawberry Cough last grow, under MH. In the same grow I had 5 of Peak's plants stretch from 16" to 22" - 26" while 8 Dutch Passion BB & SC stretch from 8" Clones to 52". The mothers stretched from 16" to 44". One compact, the other stretched.

I had some horrid stretching under HPS but that could be grower error and/or incompetence.

"MH will not produce large buds, but will assure greater bud space due to the streching. HPS will make buds large, maybe not as compact, but will not assure greater bud sites."

Agreed, but I thought the extra space was due to the smaller buds. Very ineteresting.

I don't know why the MH club like their buds better than HPS - they say it's the same potency, same taste - just bigger and less dense. My rational of reducing stretching may well be shot.

Why would someone want to flower with MH? What advantage is there?

Thanks

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Question:

When a plant goes into flower does it genetics "want" to grow the stem quickly to get height for gathering/distributing pollen or does it want to put most of it's energy into bud and resin production?

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Approximate light production:
Incandescents: 17 lumens/watt
Mercury vapor: 45-50 lumens/watt
Fluorescents: 60-70 lumens/watt
Metal halide: 90 lumens/watt
High pressure sodium: 107 lumens/watt


Metal Halide (MH)
Metal halide lighting systems are optimal for use in the vegetative phase of growing. They emit mostly blue light, which encourages vigorous growth of foliage. They are very efficient, but can get rather expensive to start with; fluorescents may seem more appealing because of their lower price, and they are not much different when compared on a lumen-to-lumen cost level. These lights can be used through-out the grow, but leave a lot to be desired in the BLOOM stage.

High Pressure Sodium (HPS)
High pressure sodium lights emit mostly orange, yellow, and red spectrum light, which is perfect for the flowering stage of the plants growth. They are (in my opinion) the most efficient type of light available for any application if you are not on a budget and can vent the grow area for heat. HPS lights can be used through-out the entire grow. They produce more dense and usually larger flowers or fruit than any other light. HPS lights are generally a little more expensive than MH systems of similar wattage. They are more commonly used by experienced commercial growers because of their ability to produce tighter denser flowers, higher lumen-output-per-watt, and will produce from start to finish.

Hobbes said:

Why would someone want to flower with MH? What advantage is there?

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I'd say that the only real advantage is that the plant grows taller and lankier, providing more bud sites, even during flowering.

Hobbes said:

Question:

When a plant goes into flower does it genetics "want" to grow the stem quickly to get height for gathering/distributing pollen or does it want to put most of it's energy into bud and resin production?

Click to expand...

Both. In the first stage of flowering a plant will try to grow taller and lankier, while in the second stage bud production begins and less energy is spent on growth. Still, during any flowering a plant will at least double in size in order to obtain more light for the buds and in order to raise it's chances of pollination.

I forgot to add, even if you choose to use MH for veg and/or flower or HPS for veg and/or flower, the difference in potency as well yeald is negligible (maybe 5%...).

HPS does pack more photosynthetic punch by producing roughly 1.5x as many photons as an equal wattage of MH..
Photosynthesis is far from the only light driven reaction cycle in plants though.. Blue light has been found to stimulate the transcription of mRNA for certain genes.. And other wavelengths have specific gene swiching jobs too..
I'm a huge fan of flowering with MH for the overall quality.. I always used a misture, and the ones more direct to the HPS were bigger/denser, the ones getting primarily MH were slightly smaller (and less dense) but tastier and more potent..
(Matching clones btw on the same hydro resevoir)

Lumens mean nothing at all to plants.. For purposes of growing they're only meaningful if you're comparing two bulbs with matching spectrums..
Lumens are a unit measured in terms of the effective brightness to the human eye of a given wavelength.. Our absorbtion peaks right around 550nm (where plants reflect most), and drops off fairly sharply/symmetrically on each side..