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CMH vs LED vs HPS
- Thread starter Gerardbutler79
- Start date
Ca++
Well-known member
That's an unusual choice for growing cannabis. It's for leafy greens. I presume it's the 3000K with both 630 and 660 added?
Tynehead Tom
Well-known member
ya I wouldn't try and flower under this HLG 600Bspec..... it's a dedicated veg light only.
My current flower run is nearly done and is under a 1000W HPS.
I did however just receive a spider farmer SF4000 to play with and I might be picking up a HLG 600 Rspec if I can make it to michigian in august for a private cannabis event being held there.
It would be interesting to section off 3 rooms and run a flower run under each light with the same strains and nutes in each room and then compare and possibly lab test each result.
I doubt I will have the time to do this and to be fair we would also need a room with a couple CMH fixtures to match the "wattage" or output of the 1000W HPS.
I do love the way that the lighting industry itself is researching and refining light technology specifically for indoor cannabis farmers. It's a great time to be alive and growing weed
My current flower run is nearly done and is under a 1000W HPS.
I did however just receive a spider farmer SF4000 to play with and I might be picking up a HLG 600 Rspec if I can make it to michigian in august for a private cannabis event being held there.
It would be interesting to section off 3 rooms and run a flower run under each light with the same strains and nutes in each room and then compare and possibly lab test each result.
I doubt I will have the time to do this and to be fair we would also need a room with a couple CMH fixtures to match the "wattage" or output of the 1000W HPS.
I do love the way that the lighting industry itself is researching and refining light technology specifically for indoor cannabis farmers. It's a great time to be alive and growing weed
Did you take leaf surface temps to compare? What were the results of the grow? What were the leds wattage? Did you measure your light intensity from both? We all know hid bulbs are hot compared to led diodes what matters is how it impacted your grow…
alpo
Active member
those are my only observations I can comment bc my grow skills is not very good. I will attach photo to show you. environment is a factor for me. LED is 260w HLG Quantum Board. This is just to show what the two CMH and LED did for me at the time same skill level making the same mistakes. your results would be better but just to show the differences for me
CMH:
LED:
CMH:
LED:
Thanks for the contribution! Both sets look pretty decent buddy. Would love to know yield from both and any additional details. Environment stuff like temps and rh through your grow. What mistakes were made etc. weve got your back!
Ca++
Well-known member
You might like that.
I thought the 5000k particularly hot, when we are told the blue light causes further opening of the stomata. I guess this quantifies 'further' for us.
The HPS is hottest, but not by a huge margin. The plant able to transpire enough to keep things reasonable. Most findings with an IR thermometer put a greater margin between things.
One odd factor, the the glass covered hps recording the highest peak temperature. All these lights were putting down 500umol. The glass covered light would of been nearer. You can see the canopy is more contoured, as we might expect from the extra far-red and IR likely present. The 3000K has the second highest spread of temps, but they are all close enough to be statistically insignificant, without really looking at the plants.
These are just my observations, presented with the pics. I think the overall idea is that non of it is that significant. What might be really telling, is that using hps, we didn't try for 500umol. We spent a lot of time seeing how close we could get. It was only after LEDs I got a light meter and really knew what I was doing with it. I thought my hps was high to spread out. Was it fuck. The ample LEDs were saying about 40K over the grow, while the hps had 70K in the middle, and 25K in the corners.
Interesting pics, I have not really known how to share.
chiesesganja
Well-known member
Air conditioning?
My Led setup literally requires none of the things he mentioned. And cmh/hps absolutely require ac
Ca++
Well-known member
I guess it's weather dependent. In general, an LED set doesn't heat the space as much, but you don't want the space to be cooler. Higher growth rates need higher temperatures than the global average of 14C. So on average, we must add heat, and LED alone isn't enough. There will be a heating bill. Again.. on average.
Higher growth rates, mean more moisture removal. If that's done through higher extract, then it's more air to heat.
I'm trying to use lighting appropriate to the season. I have a mix of LED and HID and the ratio is influanced by the seasons. In winter I coul roll out the dehu and reduce extract, but live in a trailer, so everyone would hear.
Higher growth rates, mean more moisture removal. If that's done through higher extract, then it's more air to heat.
I'm trying to use lighting appropriate to the season. I have a mix of LED and HID and the ratio is influanced by the seasons. In winter I coul roll out the dehu and reduce extract, but live in a trailer, so everyone would hear.
exoticrobotic
Well-known member
Summertime in the uk it's 34c running hids even during the night.
It's too hot to grow.
I ran leds during summer a few years back and it was doable with the reduced radiant heat of the leds, still 31c but the smoke was boof compared to hids so i don't bother anymore.
I dont want to waste my valuable strains and miss a keeper with the boof cloak in action
Summertime in the uk it's 34c running hids even during the night.
It's too hot to grow.
I ran leds during summer a few years back and it was doable with the reduced radiant heat of the leds, still 31c but the smoke was boof compared to hids so i don't bother anymore.
I dont want to waste my valuable strains and miss a keeper with the boof cloak in action
Ca++
Well-known member
At 34C we would have the lights up, then over 34C we would start pulling plugs. I once had a bar graph of yield expectations vs temperature. It's lost, but there is no real panic until 38CSummertime in the uk it's 34c running hids even during the night.
It's too hot to grow.
I ran leds during summer a few years back and it was doable with the reduced radiant heat of the leds, still 31c but the smoke was boof compared to hids so i don't bother anymore.
I dont want to waste my valuable strains and miss a keeper with the boof cloak in action
The 20-30c wisdom isn't our plants. The 25-30c is just a revision. It's 28-32 where I see the action. There are studies on soy, where 6% is lost for every day over 30c. These days will be low RH though, and so them beans are loosing weight. This corn study shows one GM brand that barely cares about a 4c change
I have certainly found that some plants don't like 34C, and will actually get deformities. Others though, don't seem to care. Keeping a good balance in your room, can mean the same yield all year, but coming from different plants as conditions favour them. Keeping my own program running is key though. Constantly bringing in new things, that don't get a good share of the space, is critical to finding the right plants. Most people mono crop with whatever they can get at the time. Giving them no control over what they grow, and so it's a lottery that I wouldn't play.
Where I have struggled is cuttings. In rockwool, the hottest of weeks would see slow progress, as many just fell. I just couldn't get things clean enough, as easily as avoiding peak temperatures. Since switching to coco with it's bio properties, this has been greatly improved. I regularly saw 38c in one place with a flat roof, and they just took a few more days. I also flowered there, and while I still got the numbers, the product was marked down. At 38c the smell is starting to leave, and you often start to smell grows on the street in these peak conditions. Just walking local towns, you smell grow after grow as the filters start letting go of what they should be storing. I have baked used carbon to test this, it's not just a theory.
Edit: That's not the actual reason I was baking it.
chiesesganja
Well-known member
I have this problem too. Some Malawi x a5haze. After I give them some 11-4-8+3mg for the whole cycle. And they seem happy
chiesesganja
Well-known member
I use 3000k kingbrite 480watts can grow some big leaf bigger than my hand.....That's very interesting. I have not had the rosetting I see online, but can't grow a big leaf with LED. Things that used to grow leaves big enough to write notes on, are just fingers now. I bet half the size.
These observations between us, really do point to something unlikable about LED light.
I will go out on a limb here, and suggest it's that single blue peak. We don't know what blue LEDs have shown blue isn't good, but can wager it's the same single peak stuff. The sun, or cmh, may have more blue, but it's not a big spike of one colour, as we see with LED. I can't think of anything else even worth looking at, to study this.
Smaller leaves, mean small were enough. Big one's come from low lighting. Outdoor I get huge ones, to use dusk and dawn sunlight, in my cold country. It's this overly small, but mainly the thickness, that tells us they don't want everything they are getting.
I have 3000K plus 660, so my blue is actually low. It's that single peak though. The one that blinds us, so is being worked out of the latest office lighting. The double blue (peaks) stuff.
Edit:
Article about the more sun like spectrum that we could have, and has been around for a few years.
Bridgelux announces Thrive series LEDs with uniform and broad SPD
Unique two-pump design broadens spectral energy in the blue region and enables the Bridgelux Thrive family to offer a relatively uniform SPD across the human visual range.www.ledsmagazine.com
Edit2:
This is the bridgelux double blue (thrive/vesta) in 3000K, vs their usual 3000K LEDs in a few different cri's
While no 3000K has a particularly high blue peak, we can see how the twin peaks give a flatter output. More in the upper and lower 400s, but less in the middle 400s.
The other curve of interest
So the twin peaks isn't going mental on the chlorophyll B production, at the expense of the carrots and purple ribbon (Yes, I have reached my limit)
E3:
That's a fairly robust backing for my waffle. If we spin up the chlorophyll B, without offering the means to unload that energy for use, then we are doing ourselves no favours.
There must be a solid reason why blue used in testing, and our LED lights, is having an ill effect. Yet in other light sources... not so much. These recent blue studies are not saying what light source they actually used, but we can bet it was LED.
E4:
The other thing about carrots.. they are red/yellow/orange. It's the collapse of chlorophyll in winter, that leave these colours prominent in many species. We even collect them as colourings. So if you want that purple, in your purple hazy... you need your carrots.
E5:
The purple ribbon must be chlorophyll A. The one we hit with 660. It's lower peak is somewhere between 420 and 440 on our graph. Where the double blue is making 3 times more light than the single blue.
Is anybody getting onboard with what I'm seeing? Thinking about buying a ticket at least?
Ca++
Well-known member
I use 3000K Kingbrite with the 660s.
Various papers agree with me, for the reasons I gave.
I guess some are big as my hand, but I know my plants, and they are generally smaller. Due to higher light levels, with higher blue content. Verse HPS or the sun. Presuming under LED, you are not lowering illumination levels. A situation people can get in, without realising.
chiesesganja
Well-known member
I decrease it to 25% power …
chiesesganja
Well-known member
Is normal o too small ??
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