Finished my run with the 315w CMH. Week sauce!

[psyphish]

I used these for years. Extremely expensive. They last about 2 months, three if you're pushing it. Only doing it for the last two weeks would extend this. But, still crazy expensive. It ads up quick... The CMH seem to have a better longevity..

I used the Philips Retro White CMHs for a long time, great bulbs but only available in 250 and 400w. Wonder how they'd compare to regular MH bud quality wise.

 

[deepwaterdude]

OP, for all your worry and science, any change you're going to see will be proportional to how much bigger you go, insofar as space and light intensity. If you want to see changes and you're interested in what CMH has to offer, throw a dimmable 630 in there and you'll kill it.

On the CMH debate, guys are killing it with vertical scrogs and bare bulbs over a 4x4, doing especially better than HPS with sativas as has been mentioned. I don't run it myself, having gone LED a while back, but hear a lot of satisfaction/amazement with results and quality from people I trust. These guys are mainly running Phillips 715w LEC and getting absolute primo. DOn't believe me, get off your butt and find some threads.

After many years with LEDs, I believe the hype about them is much worse, prone to huge magic thinking. In the end I find that there is no free lunch, watts and coverage = grams, so I choose high actual wattage, large fixtures that cover my 5x5 easily with only moderate heat. Quantum boards, COBs and my 650w Nextlight all get great results with similar spectrum to CMH and without multiple fixtures needed for small tents/spaces, + no AC, much less ventilation. Also best light efficiency out there... if you're into science If I don't get 1.4lbs from my 5x5 with my sativas, I've really %$#@ed the pooch.

Here's the current victim at 3 weeks 12/12. 5x5 tent, 650w full spec LED, 7 gal coco fed by 2 blumats, sensi nutes. Simplicity itself. Plant is a fat pheno of A5Haze x Malawi Killer, tester from seed. I think medium and dialed in nutes/environment will do more for a plant's potential than whatever light source is used as long as comparable intensity. All that said, my friends who use CMH in similar coco do equal or better than I, from what I see. My .02.

 

[Shalako]

...

 

[ambertrichome]

OK, I am amused by your taking exaggerated myths so seriously as to get upset about them.

Things are what they are, HPS has no blue but the plants adapt to the deficiency with a little extra effort. CMH matches the sun's spectrum but will not put out more watts than are put in.
How much usable energy is absorbed by the plants determines weight of the final plant. Potency of this plant depends on many things, only one is spectrum.

That pretty much covers the facts, it does not explain the emotional response of the above post. Glad Heather did not hate on LED as that actually does get complicated.

Hortilux HPS have Blue added. 1000w Hortilux has Blue and is 1600umol+
They also make a 250/400/600, and have made these color enhanced bulbs for 20+ years.
We also use 1000w Gavitas, and bought a 1000w DE Nanolux CMH, an its didn't perform as well as the 1000w Gavita. Covers less area, and is the same PAR as 1000w Hortilux HPS..1600umole

Gavita is 2100umole

 

[Lost in a SOG]

The OP before slagging off CMHs should at least have used a PAR meter since she was changing to a new light source and had 0 idea of where to position the CMH to achieve decent PAR..

 

[Elmer Bud]

Hey Ready4! I started the 315 CMH light at the same height I had been running the 400w HPS. I was expecting the CMH to be vastly superior to the HPS. I just switched them up; even considered raising the hood up from all the hype that I read. Anyone who says the bulbs needs to be closer or repositioned please comment on why? Move the 400w HPS closer and reposition to vertical and what happens? I have an idea what happens when repositioned to vertical (more light). I can give a definite answer on what happens if 400w HPS gets to close, or moved closer in my case; I already had it close enough. Also the same height I started my 315 CMH at.

DemonTrich! The next time you comment in this thread; say if you moved your lights closer in your grow? State why you think the lights need to be closer, or why they don't? Don't be a Troll. You were asked direct questions that pertain to this thread!

One thing I would like to say about my grow and my personal setup. I can control all climate parameters, though I don't have CO2. Now while I have my temps in rang 75-81 deg. The one thing I can't do with my setup is really bring the light down low and just destroy all the heat with AC/venting etc... I just don't have the ability to do that. The 400w HPS did fine raised up 23.5", why does the 315 CMH need to be significantly closer to get same yields?

G `day HL

Higher frequency waves don`t travel as far .
Their energy dissipates faster .

Blue light is higher frequency than red.

eg you hear the bass but not the treble coming from a long way away . Bass is long waves low freq . Travels further .

By the way 4 foot from the tops with a 400 watter is too far .
You understand the inverse square law ? Double the distance get 1/4 the light .

I have plants within 6 inches of 600 watters till the stretch is over . Raise them every cpl of days and super crop for even canopy .

Thanks for sharin

EB .

 

[Koondense]

Not true.
Energy dispersion is different when comparing sonic and EM frequencies.
The stars would all look red(actually invisible to our eyes) if what Elmer sais would be true.
Red and blue travel the same way through space.

Cheers

 

[heatherlonglee]

Elmer Bud, quoted me but can't read or comprehend that 23.5" is just under 2 feet?

Read my posts in this thread! I've already told you why, and what bulbs you should be using.

 

[Switcher56]

I've read this entire thread. Someone quoted long ago that the definition of insanity is doing the same thing over and over again, expecting different results!

 

[Elmer Bud]

Elmer Bud, quoted me but can't read or comprehend that 23.5" is just under 2 feet?

Read my posts in this thread! I've already told you why, and what bulbs you should be using.

G `day HL

OK , I`ll make it simple so you can understand .

Your lights are too high .

@ Koondense .
Traveling in a vacuum I agree . This not a vacuum .

This is true only when light travels through some medium where scattering can take place. The intensity of the scattered light by a particle is inversely proportional to the fourth power of its wavelength, which means shorter wavelengths are scattered more strongly. This implies the energy of shorter wavelengths get dissipated faster in the form of agitation of molecules and they penetrate lesser distance than long wavelength light. This is the reason why the sky appears 'reddish' during the evenings. Due to sun's relative position near the horizon, the light has to cover a greater distance and the "bluish" end of the spectrum is scattered away in its early stages of traveling the atmosphere, leaving the reddish hue.

https://www.quora.com/Why-do-long-wavelengths-travel-further-than-short-wavelengths

I think the factor I was wanting to talk about is the absorption of blue light and the penetration of red light . It was late ...

Thanks for sharin

EB .

 

[frostqueen]

After several rounds of 315, I guess I'll chime in and say that I get slightly better yields from CMH than I get from HPS on a grams-per-watt basis, all other factors being equal. I still use both. I also like conventional MH and still use it in veg quite a bit. Those will likely eventually be replaced with CMH, though.

I don't notice much reduced stretch as many others report. I do get some beautiful pistil pigmentation from strains that didn't show it under HPS; healthy pistils with pink or magenta hues. Resin development is similar to HPS for me. They do seem to finish just a bit earlier. 315s definitely run a lot cooler; I love that part.

These are really ideal for a one or two light breeder cabinet or small grow. If doing production work I bet 8 or 16 or 800 of these would pay for themselves pretty quickly, and the savings on bulb costs and electricity alone are significant enough to heavily factor in for professionals looking to trim costs.

Long story short for me is that between the cooler operating temps, the lower power draw, the full veg and bloom compatibility, and crucially, the loooong lifetime and low cost of the bulbs makes 315s a good choice for me.

I can see how it might not be best for some people like OP, and will just put it out there that something doesn't suck just because it didn't work out in your situation. Just use what works for you and move on.

Different things work differently for different people, and IMO there's no need to get butthurt and disrespectful over someone else's different opinion. This hasn't been a discussion as much as it's been a monkey knife fight. Lighten up, people. Rise above it.

 

[Elmer Bud]

Not true.
Energy dispersion is different when comparing sonic and EM frequencies.
The stars would all look red(actually invisible to our eyes) if what Elmer sais would be true.
Red and blue travel the same way through space.

Cheers

G `day K

Learn somethin every day . Appreciated .

Thanks for sharin

EB .

 

[Sign]

I finished my first run with 315cmh. The landrace mazar I Sharif had issues, light burning and maybe a calcium deficiency. However, the wide leaf pheno got fat and frosty, the narrow leaf was spindly and really didn't grow well although it finished it's seeds fine at least. The hash plants grew great, no issues whatsoever, is it because they've been grown under artificial lights for many generations and are acclimated to a fake sun? I don't know.

Unfortunately the variables were a new light and a new strain in regards to the cmh and mazar respectively, I won't judge either the light or the strain until I've done another couple grows at least with the same variables.

Had I not run the mazar on my maiden voyage of the cmh I'd have thought it did an amazing job.

 

[Koondense]

Elmer,
you're partly right because of atmospheric scattering, but that needs a lot of atmosphere and does not significantly apply to grow lights simply because there's not enough atmosphere between lights and plants.
You're also right about another thing... every day we learn something. Life is awesome

Cheers

 

[NzGreenWhanau]

Thanks for the info

Thanks for the info

Yeah I'm here to hate on the 315w CMH! Already hit a few other threads! It's nothing but a 315w bulb. It's 315 watts, and it puts out 315 watts of light. It's not equal to anything larger, nothing like a 400 HPS. Don't even think of building a grow room around these thinking you're getting 600w HPS type light intensity. The info out and about (no finger pointing) on these bulbs is wrong. My light meter says they're less intense, my eyes say it's less intense, and also my HARVEST says the light is less intense. I'm happy with quality of buds sure. But the loss of harvest size is just way to much to justify the switch.

To anyone who posted anywhere that 315w CMH is better than or equal, or even close to a 600w HPS

I have been doing my home work on purchasing another light for my tent an was an had been reading alot of reveiws on this forum an others but the information you posted from the University of utah an you own posts as made me stick with hps. Thanks

 

[Elmer Bud]

Ceramic Metal Halide Light Guide + Review

 

[heatherlonglee]

Images below taken from eyehortilux.com

It was never about one bulb or spectrum of light.

 

[Shalako]

i would say a single 315w can match a 400w, a 630w cmh will leap ahead of a 600w hps and i dare say 3 x 315w will blow away a 1000w HPS especially if your smart with them. effectively you could cover a 3x12 tray with 3 315's

I agree with what your saying completely and with the right strain and multifeed DTW you can do a great job with 3 or even 4 315's over a 3 x 12...quality being the most important factor to myself v.s total weight with more cost with HPS.

 

[gaiusmarius]

this has been interesting, thanks for sharing your experiences. i'm thinking of making the switch from 2x600 digi hps units to maybe 3 x315 cmh. don't like to read that they lack penetration though. the space is a wooden floor to ceiling box thats 220cm long and 110cm wide, so my 2 x 600 watt is a bit over kill for the space, it gets me from minimum 900g to max around 1200g, depending how well i pay attention, time of year, strains used etc. was thinking to replace the 600 with 315, but that might be under kill, with 3 units ill still be saving 300 watts or so energywise. if i can maintain my gpw numbers it will already be worth it.

ps: do you have different bulbs for flowering and vegging?

 

[ambertrichome]

2 x 600w HPS isn't overkill in a 4 ft x 3.5ft ( 122cm x 110cm. foot space ).

85w-sq/ft. The sun is 100w-sq/ft on average.