Ceramic Metal Halide (CMH)

[GreenThumb14]

I have to go chop, but......
First 30 day table is under:
Pro Grow 260 = 218w
HML leds 2x80= 160
That would be 42 watts sq ft on the first table, but the plants under the HML's are at 27 watts a square foot and do better than the Pro Grow.

Last 30 day table is under the 315 Agro at 35 watts a square foot.

The last harvest was right at 2000 grams wet. came out to about 440 grams dry plus what I took out to test.

I'll take pics before chop today.......

You seem to get really good yield with the 315w agro... Are you running that on a mag ballast? I'm trying to get an idea of what type of yield I would get with the 250w CMH on a digital ballast, all other aspects being good such at nutrients, etc.

 

[tenthirty]

Ballasts are fleabay philips used.....
The yield will be dependent on the grower, room, strain, and the degree of being dialed in.

 

[GreenThumb14]

Right, like I said if all else where the same, IE you switched to a 250w cmh. I'm just having a tough time realizing what type of yield I'll get from a 250w.

 

[tenthirty]

You won't know until you do it!
Start a grow journal.

Too many variables to guess.

 

[GreenThumb14]

Waiting on some more components to arrive then I can start. I just really wanted the 400w CMH setup but didn't want to not use a digital ballast. I can't have the hum of a mag coil ballast.

I'll definitely start a grow journal here. I'm not an experienced grower but I've been fiddling around the past few months and am getting the hang of hydro. Been having mixed results but lately I've been having a lot more success as I play with some bag seeds. Most of my experience is with outdoor vegetable/fruit gardening.

 

[tenthirty]

The tale of the scale.

All harvested, not my best, but pretty good considering 315 watts and my lack of growing skills.
There were some Sweet tooth #4's in there and they yield less than the alien dawg. and the mom was not in the best of health, after it was hit with root aphids it was never quite right and the clones exhibited the same lack of vigor. (soft420 seeds)
Mom has scenes been 86'd.

Wet weights:
There were 8 runts less than 30g each. (mostly Sweet tooth)
Heaviest plant was 68g.
Average was 41.7g per plant.(9.2g dry when it gets there)
Total wet weight was 1752g. (385g dry)
1.22grams a watt under from 27 to 35 watts a sq ft.

It was a lower than average grow, too many runts.
The light was not the problem, my mistakes were!

Here is a 54g budsicle, This would be representative of 1/3'd of the harvest. (50+ gram plants)
The rest were smaller.

 

[rives]

What do you think was causing the stunting of the Sweet Tooth? If that was SOTF420's version, it seems like it is usually a pretty good yielder. I know that I screwed some up with too low of magnesium before I started using V+B. They seem to like a lot of mg, and LED's seem to accentuate that need.

 

[tenthirty]

The roots were attacked by root aphids. I think that she got some kind of infection that would pass to the clones. But that is just a guess.

Leaf claw, few leaves, small flowers. It did fine until the root aphid attack, but then it went down hill.

Basically, all the moms in the mom room were effected and have finally been replaced, though an AD mom just dried up and died last week, but she was over a year old in a water farm, had pretty nice roots too.

I usually get about a year out of mommie plants with the waterfarm anyway.

A different method may be in order, but the current setup requires so little time and maintenance.

Both the AD and the SWT#4 were well over 400 days old at their demise.

I do have more seeds from SOFT420, so not a huge loss.

 

[GreenThumb14]

You harvested 13oz dry from a 315w cmh?! I'm impressed! I was reading a post where a guy pulled 8oz dried from a 400w mh/hps and I thought that was really good.

So since I'm a n00b to this, would you say that the balanced spectrum from the CMH really helps with yield despite using a lower wattage lamp? Are you able to get the lamp closer to the canopy because of it burning cooler?

 

[Nader]

fuckin two more broken 830's!!!!

 

[tenthirty]

You harvested 13oz dry from a 315w cmh?! I'm impressed! I was reading a post where a guy pulled 8oz dried from a 400w mh/hps and I thought that was really good.

Thought bubble......
Ya, 1.2 grams a watt is very good and this is within the realm of what a 600w HPS would produce..........
but
A good sog grow averages between 10 and 15 grams per plant. This cycle averaged 9.2 grams.
The largest plant was 68g wet. (14.96 dry)
With >500 umol/m2/s with a shade adapted plant the limiting factor becomes canopy management. My errors were within this arena.

Goal.......
15g a plant..... 630 grams total.......2g watt.
On paper this is what is looking possible.

So since I'm a n00b to this, would you say that the balanced spectrum from the CMH really helps with yield despite using a lower wattage lamp? Are you able to get the lamp closer to the canopy because of it burning cooler?

No closer with the light, but the health of the plants were much better than I have ever encountered under HPS.

 

[GreenThumb14]

fuckin two more broken 830's!!!!

How are you breaking them? Experimenting with different ballasts?

 

[GreenThumb14]

Thought bubble......
Ya, 1.2 grams a watt is very good and this is within the realm of what a 600w HPS would produce..........
but
A good sog grow averages between 10 and 15 grams per plant. This cycle averaged 9.2 grams.
The largest plant was 68g wet. (14.96 dry)
With >500 umol/m2/s with a shade adapted plant the limiting factor becomes canopy management. My errors were within this arena.

Goal.......
15g a plant..... 630 grams total.......2g watt.
On paper this is what is looking possible.




No closer with the light, but the health of the plants were much better than I have ever encountered under HPS.

Very nice to know... I have considered putting a 250W HPS in the air cooled hood along with the 250w CMH if it turns out that I need/want more light. I read on other sites that it's a very good combination. Any thoughts on it?

I'm doing a 3x2' scrog in a cab... I guess if I want to get 500g+ harvests I would probably need to add more light?

 

[Nader]

How are you breaking them? Experimenting with different ballasts?

They're arriving broken. Just so poorly packaged both times...
but I am going to test one in a M141 (pulse-start) and one in a M47 (regular magnetic) to see which, if either, produces better results with the 830.

 

[tenthirty]

Very nice to know... I have considered putting a 250W HPS in the air cooled hood along with the 250w CMH if it turns out that I need/want more light. I read on other sites that it's a very good combination. Any thoughts on it?

I'm doing a 3x2' scrog in a cab... I guess if I want to get 500g+ harvests I would probably need to add more light?

250 watts of CMH gives you 42 watts sq ft. (plenty with a good reflector and walls)
Don't under estimate the importance of the luminaire and wall reflectivity in such a small space. (the smaller the space the greater the wall effect. "Orca film")
Based on my ideal sog 360 maybe 400g.
The limiting factor will be how many colas will fit!
The second factor is learning how to grow colas! (maybe the first)

Don't be disappointed if the first few grows are at .5g a watt. (We all went through this.) Well maybe more than a few.

For SCROG, Reves would be the authority. I would suspect it might be more.

 

[rives]

I think that 500+ grams from 6 square feet is a pretty tall order. Lighting density aside, simply the amount of real estate becomes a factor. My scrog is 30" x 30", or 6.25 square feet, and I've yet to hit a pound. I don't grow varieties that are exceptional yielders, but I've had some pretty good looking screens that did a high of about 400 grams. The only place that another quarter-pound plus could have gone would have been vertically. It would take a pretty careful choice of genetics, and some damn good training in addition to the lighting.

*edit* I thought that I should add a bit of detail since my method is so different than tenthirty's. Despite the wide variations between our two approaches, it looks like our yield per square foot is damn close. I normally average 3-4 ozs per plant and have been as low as a little over 2 ozs when growing Sour Bubble. I grow either 3 or 4 plants in 3 gallon air pots (coco, blumats, and V+B). It might just be possible to fit a fifth pot in the middle, but it would make it completely impossible to work under the screen. I've found that there isn't a hell of a lot of difference in yield between 3 and 4 plants (I doubt that it is anywhere near 10%, much less the 33% that you might expect), it just takes a little bit longer to veg out the screen and it is much easier to work on.

 

[GreenThumb14]

I plan on growing 1 critical sensi star out of a 5g bubble bucket. Supposedly yields pretty good in scrog. Vertical height is where I am challenged, so how close can I let the CMH get to the canopy? Is heat the limiting factor? I picked up an eBay air-cooled hood, looks like standard fair... It covers up to a 4x4 area. The walls in the cab are lined with reflective backed insulation.

Not sure if I can post links to other forums here, but I was reading a grow journal where this guy pulled 8.5oz dried (27oz wet) from a 6sq/ft critical sensi star scrog in a tent under 400w hps. I plan on basically following exactly what he did. Only difference is I'll be using some supplemental CO2.

Thanks for the input tenthirty, rives.

 

[rives]

I've never used CO2, but I don't think that it is going to double your yield.

 

[Azeotrope]

GreenThumb - I am in a fully enclosed set-up using CO2 and rives is correct. It will not double your yield. When applied correctly with reasonable temp, humidity and nutrient parameters, it will allow for maximum growth rate and if you had all of those dialed and then added CO2, a yield increase should be seen. However, as I found out recently, everything else has to be dialed.

For example, I was on track for a great cycle, but had an unfortunate moment that put my girls in 121F for about 30-45min. Lost some tops and deffinetly slowed them down. Recovered now and on track, but all the CO2 in the world won't fix that moment.

Please also note, that there is a lot of "old mythology" regarding CO2 and running higher temps and really high PPM of CO2 as the way to go. I would suggest looking for Spurr's good write ups on why a dialed in +80f lights on and +70F lights off and right around 1000ppm is very reasonable.

At any rate, don't get too excited and go nuts with the set-up....... Make sure you test and dial in everything and that may take some time.

Best of luck to you! Azeo

 

[Azeotrope]

Allright CDMers, I decided that with rives running the 930, Tenthirty running the Agro and the bit of time I had the 930 going that someone should run the 942. So, I have switched out at day 19 12/12 to the 315w 942 "open" rated. I had not run a grow without the main source being the Philips retrowhite 4k CMH since the week of their release many years ago. The girls I am working now are well known to me (I made the cross and have been running them for a few years), node spacing through the stretch was greater than I am used to with the 930. Nothing dramatic and I have played with some other factors a little this time.

I just decided that the 942 should get some testing and I really like the spectral graphs that are published for it.

I will update with pics in a week at day 28 and see where things are at.