All COB Users - Lettuce Grow Challenge!!

indianajones said:
www.luxtech.com sells strips using the LM561C.

same that you would buy from alibaba, but made in america.

i did some basil, parsley, and radish under my COBs, it worked really well. the radishes were small, but i don't think they liked the 24 hours of light they were under at first. when i put them under 16/8 they really took off.

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did i read that right? they have a light you can adjust the color temperature?

http://luxtech.com/wp-content/product_datasheets/Dynamic-White-One-Pager.pdf
 
indianajones said:
yup, they're gettin' fancy with it now.
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I'd be more excited, but im not that good of a grower that the ability to switch light colors wouldn't matter much. I would probably make it worse. :) that being said, it is pretty cool. What do you suppose the trade off would be on this?
 
muleface said:
I'd be more excited, but im not that good of a grower that the ability to switch light colors wouldn't matter much. I would probably make it worse. :) that being said, it is pretty cool. What do you suppose the trade off would be on this?
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cost fer sure!
 
muleface said:
I'd be more excited, but im not that good of a grower that the ability to switch light colors wouldn't matter much. I would probably make it worse. :) that being said, it is pretty cool. What do you suppose the trade off would be on this?
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It looks to me like they're using two different LED coatings to get the spectrum changes. My guess is you'd have to dim one to have another be dominant. The dark orange is probably 2700k and the yellow is probably 6500k. So the 2700k setting is full power on the orange side, dark on the yellow side...and vice versa or various shades in between. The sacrifice is less overall intensity, but "theoretically" crafted towards what a plant would absorb more of at the time. It's almost like those "veg/bloom" switches where you're turning off half the LED's to achieve a more red or blue spectrum.
 
Quick update. They have been under the lights for about a week now. I was sent a packet of Kweik Butterhead lettuce instead of the Oak Leaf lettuce so that will take its place.

2700k
cuEjZvI.jpg

3000k
y3Y2P4i.jpg

3500k
rTJmKTU.jpg

4000k
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5700k
JaqwUKl.jpg

Seeds
3TcKadj.jpg
 
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RandomHero8913 said:
Quick update. They have been under the lights for about a week now. I was sent a packet of Kweik Butterhead lettuce instead of the Oak Leaf lettuce so that will take its place.

2700k
cuEjZvIm.jpg

3000k
y3Y2P4im.jpg

3500k
rTJmKTUm.jpg

4000k
99M8oasm.jpg

5700k
JaqwUKlm.jpg

Seeds
3TcKadjl.jpg
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I have heard head lettuce is much harder to grow indoors than loose leaf, is that true?
 
RandomHero8913 said:
Quick update. They have been under the lights for about a week now. I was sent a packet of Kweik Butterhead lettuce instead of the Oak Leaf lettuce so that will take its place.
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This is really great. Thanks for stepping up here. I have absolutely no doubt that lettuce will grow under each light without any problem. I am very curious to see how each head develops. Things like are the leaves thicker under 2700k light vs 5500k, do the heads develop more symmetrical under different lights, do they grow faster, does it make any difference at all? Please continue to send picture updates. If its not too much of a pain, at least weekly would be nice.
 
Yodaweed said:
I have heard head lettuce is much harder to grow indoors than loose leaf, is that true?
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I have found this to be absolutely true. It seems like almost any led can make a "leafy" variety grow but when it comes to forming heads they just kinda run out of horse power.
I have noted some start making smaller and smaller or same size leaves rather than larger like under sun or other light sources.
That is why I encourage others to grow "Rex" or similar. We can all get a good look at a nicely formed bibb lettuce at the grocery store in those plastic clamshells

Perfect example right here: note that the leaf variety is growing a lot of leaf although starting to look a bit mutated. But the texture is good under this light source.
Rex however is starting the "run out of horsepower" thing I mentioned. Notice the new leaves are starting to get smaller rather than larger and it is staying more open like a flower structure than beginning to form a head.

IMG_1174.jpg
 
DWC beefstake tomato update, this is the one with no airstone, just a tiny pump at the bottom of the bucket that turns on every two hours for 15 minutes to mix things around, almost 3 months and the roots are still nice and white..

tomatoes were growing a little slow with just two 14.5w bulbs so i added two more 2700k bulbs and this shit has exploded.

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picked my first today, was pretty tasty...
 
Diysystem said:
Well seems that i have to do everything myself as no one here are intrested in spectrum respond in lettuce anymore.

I have orderd XP-G3 cold white, neutral white and warm white. LM561C 3000k, 3500k, 4000k and 5000k strips. XT-E royal blue and XP-E photo red.

Will do the following test in the next 6 weeks to se how lettuce respond to different light recipes.

XP-G3 cold white only
XP-G3 neutral white only
XP-G3 warm white only
XP-G3 cold white + 660nm photo red 75/25
XP-G3 neutral white + 660nm photo red 75/25
XP-G3 warm white + 660nm photo red 75/25
LM561C 3000k only
LM561C 3500k only
LM561C 4000k only
LM561C 5000k only
LM561C 3000k + 660nm photo red 75/25
LM561C 3500k + 660nm photo red 75/25
LM561C 4000k + 660nm photo red 75/25
LM561C 5000k + 660nm photo red 75/25
XP-E photo red + XT-E royal blue 60/40
XP-E photo red + XT-E royal blue 75/25
XP-E photo red + XT-E royal blue 80/20
XP-E photo red + XT-E royal blue 90/10

Test period 30 days from seedling. Biomass, texture, structure and dry weight will be recorded

Hope this thead will go back to its roots soon
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Any progress on this Mega-Test @Diysystem ?
 
Dreddd said:
DWC beefstake tomato update, this is the one with no airstone, just a tiny pump at the bottom of the bucket that turns on every two hours for 15 minutes to mix things around, almost 3 months and the roots are still nice and white..

tomatoes were growing a little slow with just two 14.5w bulbs so i added two more 2700k bulbs and this shit has exploded.

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picked my first today, was pretty tasty...
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That's a fatty , very nice, looks great for a burger or sandwich.
 
So far its looking like redder is better for these young lettuce plants. To test this further the Mizuna has begun sprouting today. I'll take some pictures on Saturday as that will be the two week mark for the lettuce under the COBs.

On a side quest to see what the hell will happen I've wired nine V18's up to a single 560ma driver in series/parallel. So each COB is getting about 187ma. I got some Tomatoes and peppers under those.
 
RandomHero8913 said:
So far its looking like redder is better for these young lettuce plants. To test this further the Mizuna has begun sprouting today. I'll take some pictures on Saturday as that will be the two week mark for the lettuce under the COBs.
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This is very interesting and somewhat counters what is thought to be common knowledge in indoor agriculture lighting. I love the experiment you're doing.

I'm wondering if you've factored in the ~13.5% lumen output difference between the 2700k and 5700k outputs. I'm curious if you could measure lux output differences at the plant to see if there's an overabundance with the bluer spectrum light? That much of an output difference could possibly put PAR exposure over the top for lettuce. Particularly if the previous PAR calculations were based on the lumen output of the 2700k COB, which would mean theoretically the 5700k is pushing 13.5% more PAR.

I'm using COB's to start garden seedlings and have had to play with the output via the potentiometer quite a bit to dial in the lighting. It's a very interesting type of lighting, but does require some fussing on general plants I'm learning.
 
@robincnn if you could fill in blanks on the specs of the light it would be great.

So I'm excited to be doing a side project/experiment.

I have a lumileds @ 12.5

This strip is about 36 inches (i didn't measure before I mounted it)

It is pulling 26 watts at the wall, it is at 12 inches of the table, about 10.5 inches off the top of the rockwool, It is late right now, so i didn't cut the posts down. Any thoughts on how far off the tops it should be would be appreciated.

There are 2 seeds per rockwool cube. I have a mix of vermiculite and perlite in bottom of the container. There is light nutrients in the water.

The only consistent light these will be getting is from the purple strip. The lettuce was picked at random from my seed bin, they are in alphabetical order in the cubes. I have 4 varieties of lettuce.

I will run at 24 hours a day for the next 2 weeks.

Not sure what I will do yet after 2 weeks. There isn't enough space to grow 4 plants to full size. or maybe there is?

top left is buttercrunch
top right is cimarron
bottom left is parris island cos
bottom right is ruby
 

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