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

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 went from a 400w hps to the 315 and have had exact opposite results on mostly landrace sativa based strains. I would never go back to 400w hps for flowering.

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.

I have been growing sour bubble by BOG for 5 years now with great success. Using 4K MH to flower for the first 3 weeks and then switch to HPS to finish the last 31/2 weeks.
During the last run I decided to flower 2 plants using 315w 930 Phillips CMH, open fixture for 4 weeks and finish the last two weeks with 600w HPS in a 4x4 tent.
The results were disappointing. While trimming this harvest I noticed the buds were smaller and the leaves around the buds were larger then usual. The plants produced more good trim and smaller flowers. The good news is the buds were as frosty as ever before. Less flower and more good trim.
I'm just sharing one man's experience with one grow and one strain.

Hey mj418! I'm considering doing something similar to what you describe on how you grow from now on with the CMH. Use CMH it for first few 7-14 days of flower (depending on wether you want stretch or not) then switch over the to HPS for the main part of flowering cycle, then finish the last 15-19 days with the CMH. The CMH pretty white light and less heat at the end of flower should do some good. I run my strains pretty long in the 64-70 day range.

Do the CMH lights not penetrate as deeply into the plant canopy, compared to HPS, perhaps? Never used one myself.

the smoke quality under 315's was at least as good or much improved. I believe based on the experiences i'm getting that anyone can now grow landrace sativa based strains; you don't need to live in an equatorial type environment to enjoy these strains. there was an overall huge improvement if talking about smoke quality from my own personal experiences. I am not in favor of trying to grow landrace sats under 400 w hps. maybe it's a strain based thang? I don't know. I am super happy with the quality improvement i'm seeing from the 315's.

i'm not saying that 315's are the best yielding lamps.


i'm comparing 400w hps to 315 w cmh.


i'm comparing landrace sativas or predominately landrace sativas.


i'm able to effectively grow in approximately 50% more area under the 315's than the 400w hps. the best place to finish flowering the plants under 315's is at the fringes of the 3 x 3 sq. ft area. I emphasized finishing area. until the plants are finishing stretch time I keep 'em closer to the middle. I used to have to defoliate the landrace sats under the 400 w hps to help minimize stretch. I don't have to defoliate under the 315's.

I pulled 3 1/4 lbs off 945watts using those bulbs. Best gpw I ever had.

I pulled 3 1/4 lbs off 945watts using those bulbs. Best gpw I ever had

Click to expand...

cmh, hps?

I have high expectations for the chm. I read a lot of reviews that say there is a large jump in grams per watt but all say you need to run multiple lamps to equal a 1000w de if you have a big garden. how much should you expect from 315 watts? I could see a let down from all the hype I've heard on these things. it's impossible to live up to some of the expectations.
Someone told me the other day they saw a test grow out of Colorado where CMH yielded around 30% more in 50 days with less watts. compared to SE HPS finishing in 65 days. I told him that's too good to be true.

I have no experience flowering with this type of lamp yet.I'm currently vegging under a kit from china, 2 315w cmh end to end.From my point of vew the plants look happier but i'm only been using it about a week. I'm sure some of you have seen these. It was hard to beat the price at the time $300usd. I would prefer 2 separate reflectors for better light distribution. But a single 315 cost kit cost as much at the double. Any one have any insight into these kits? let me know what you think /like /hate about em. also iof anyone could link me up some alternative kit single lamp they prefer that are cheaper, or better would be great. What setups are most people using these days? I'm more of a plug and play guy myself. Don't really care to call up electric supply store and chase down ballasts and put em together but welcome all suggestions.

if i was believing all that hype going into a run with a cmh it be hard to live up to those lofty expectations. I always have to manage my expectations. Be it with new beans or new gear. For example before i Purchased this kit I had done some reading on 315w CMH lamps and was under the impression that these things put out almost no heat. Now keeping in mind i have 2 x315w running end to end with about 3 inches separating them. I'm finding that this thing isn't as hot as a 1000w hps but its still throwing a considerable amount of heat.

I think it's good to have a thread where people can point out some of the down falls of this lamp ballast set up.

I hope the 315w Phillips are as good as they're 'hyped' to be because I bought eight of them... four each 3100K and 4200K.

The only thing I'm unsure of is whether I should supplement with UVA/UVB and/or ER/IR.

The quality of the buds is great no doubt. If you have high temps or low humidity at the end of flowering cycle, I could see these bulbs helping considerably. If you have limited ceiling height the CMH would be a good choice. I've fried a tiny tip off a nug or two with HPS back in the day. I had the CMH lights in the 23.5" range this grow, moving down to 22" for next run. No promises I won't be dropping the HPS back in for weeks 3-7 on a ten week flowing run. I really want to give the CMH another full run. It seems important to point out that the CMH isn't a stronger light source so it will need to be considerably closer to achieve similar yields as a more powerful bulb.

I went from 3x600hps to 4x315 and got just about the same yields, but with less power. This run now, ill get above, the next run I'm gonna absolutely KILL it.

Please don't blame the light. It's just that, a light.

630 watt DE CMH

630 watt DE CMH

Has anyone run this DE 630 watt CMH? Im thinking about getting one. They have a 4' footprint of light. Should work in a 5x5 tent


http://growershouse.com/growers-choice-horticultural-lighting-630w-de-cmh-complete-fixture

idiit said:

cmh, hps?

Click to expand...

945w = 3 x 315

Hey DemonTrich! I didn't comment on your reply before on the other thread because I didn't want to attack everyone who posted. You got "just about the same yields" using the CMH? I'm not at all interested in hearing about you counting chickens before they hatch on our next run. Your harvest that hasn't finished yet means absolutely nothing here.

I like the term weak sauce, used it once somewhere on a forum. Your description of a good light kinda reminds me of weak sauce.

An experienced grower knows his grows.

now im missing the negative rep

Lots of members stating that plenty of people have had good results, great results or people killing it or some other comment uselessly similar about the 315w CMH bulb. I'm going to try to explain this one more time! The CMH did grow good weed, and it looked smelled, tasted fine. What it didn't do was completely obliterate the harvest weight that a 400w HPS bulb can produce! The CMH didn't even compare in weight and bud density. The weight of harvest wasn't the same and thats my point! Not that my grow was trash and un smokable. I didn't get the weight that I got before with same setup using the 400w HPS. Also again I moved the light closer for the CMH because I could see plainly with my eyes it wasn't as bright.

In my real world experience; changing to the 315w CMH didn't out perform a 400w HPS bulb. Don't come here talking about good, great, killing it harvests! Definitely don't be talking about how the 315w CMH is close to a 600w HPS!

I didn't change one thing about my grow setup. I changed bulb/ballast and nothing else and got less weed! How many of these silly comments about good, great, killing it harvests can say that they changed nothing else but the bulb? If they can they haven't, and well I have!