All COB Users - Lettuce Grow Challenge!!

Johnnycannaseed1

Johnnycannaseed1

Well-Known Member
OneHitDone said:
I
It's interesting that a 4ft T5 that costs only $3.20 can deliver this spectrum:
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Huh why do you say that:shock:....

Back in the day I used to run Phillips Master Tl-D 840 36watt 3000k warm white tubes 8 per 1.2m2 area for a total of 288watts and I was able to get yields comparable to 600watt HIDs, the reason being I could literally have the tubes touching the plants, plus the light was equally distributed over the area, whereas by the time I had hung the 600watter far enough away from my plants (so as not to cook them) the amount of light falling down onto the total canopy area was comparable to the fluoro's

The issue as far as I see it, is most who tried fluoro's treated them like HIDs and usually ended up hanging them to far away from the canopy, hence their lack of results.....Having said that 4 footers were great for scrog but not so good for taller plants.
 
Johnnycannaseed1

Johnnycannaseed1

Well-Known Member
@robincnn your previous DLI of 17.28mol/m2/d was on the upper end of good, what Ec were you feeding your lettuce at?

It will be interesting to see what happens at 500 μMol/M-2 S-1 because that will be pushing your DLI up to 28.8mol/m2/d.

Check the cornellcea literature below, in there the highest they recommend is 17mol/m2/d.

http://www.cornellcea.com/attachments/Cornell CEA Lettuce Handbook .pdf
 
robincnn

robincnn

Well-Known Member
Johnnycannaseed1 said:
@robincnn your previous DLI of 17.28mol/m2/d was on the upper end of good, what Ec were you feeding your lettuce at?

It will be interesting to see what happens at 500 μMol/M-2 S-1 because that will be pushing your DLI up to 28.8mol/m2/d.

Check the cornellcea literature below, in there the highest they recommend is 17mol/m2/d.

http://www.cornellcea.com/attachments/Cornell CEA Lettuce Handbook .pdf
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Soil grown. I have dimmed it down to 300 μMol/M-2 S-1 so 17.28mol/m2/d
Thanks I for the link to handbook.
 
Johnnycannaseed1

Johnnycannaseed1

Well-Known Member
No probs;) and turning it down sounds like a good plan you might even get away with lower because I did a tomato experiment not too long ago using a 600w HID vs 220w LED vs 150w LED which produced some interesting results at lower light levels, I will post the experiment in full here either later on today or tomorrow:peace:
 
OneHitDone

OneHitDone

Well-Known Member
I would have to take issue with "too much light" and "too high of temps"
The lettuce I have in my full sun orientation Greenhouse does not frizzle fry mid day even seeing temps hovering near 100° so I would have to say it is more like "too much of the wrong light"
This topics is very interesting and shows that cannabis is very forgiving on light recipe compared to other plant species. One just had to wonder from a quality standpoint, what are many missing in their cannabis plants that could be attained under a true "full spectrum" source that would satisfy all plant species?
 
Johnnycannaseed1

Johnnycannaseed1

Well-Known Member
OneHitDone said:
I would have to take issue with "too much light" and "too high of temps"
The lettuce I have in my full sun orientation Greenhouse does not frizzle fry mid day even seeing temps hovering near 100° so I would have to say it is more like "too much of the wrong light"
This topics is very interesting and shows that cannabis is very forgiving on light recipe compared to other plant species. One just had to wonder from a quality standpoint, what are many missing in their cannabis plants that could be attained under a true "full spectrum" source that would satisfy all plant species?
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Ah here is the thing ...you need to base your observation on the total amount of light your plants received during the day, don't forget the sun is not at full strength everday all day and also don't forget the sunlight has to pass through your greenhouse panes so there are going to be losses.

That's why working out the DLI is so important, ideally you would want to measure how much light you are actually getting in your greenhouse on an hourly basis then after one complete day you would work out the daily light integral your plant received... you may well find your lettuce is only getting 14mols a day.

With regards to cannabis I found in the past that a switching light spectrum throughout the grow generally produced the best results.
 
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SSGrower

SSGrower

Well-Known Member
@OneHitDone can you elaborate on output power of your 5k led pannel? Agreed totally on forgiveness with regard to light source. Until there is a type of photoactive phosphorous or other coating for leds we will be lucky to have modest improvements in chip performance for flux and color accuracy as the bulk of use will benifit from that.
 
OneHitDone

OneHitDone

Well-Known Member
SSGrower said:
@OneHitDone can you elaborate on output power of your 5k led pannel? Agreed totally on forgiveness with regard to light source. Until there is a type of photoactive phosphorous or other coating for leds we will be lucky to have modest improvements in chip performance for flux and color accuracy as the bulk of use will benifit from that.
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I don't have a 5K led panel
Would like to try either 6500K or my "secret sauce" idea
Working towards both of those tests in the future.
I just freed up my Vero18 3500K tent so am going to try some lettuce there along side a cannabis veg to see with my own eyes what is going on with a cct like that and lettuce
 
SSGrower

SSGrower

Well-Known Member
OneHitDone said:
Field grown quality heads of lettuce indoors under lights ;)
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So it seems that @thetr33man and @OLD MOTHER SATIVA may not be seeing, or at least to the extent the rest of us did the difference in color/texture. If I remember correctly they each have cidly light bars in either blurple or mono red and blue as part of their regimen.

I personally did not like the taste of my salad bowl lettuce regardless of if it was inside under led or outside. The outside was much more purple and crisper. The romaine was better but still weak and floppy, I am not convinced this is totally because of the led because I had little if any direct airflow (wind). Light is important but so too is environment.
 
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