CXA3070s for Growing Indoor Fruit and Vegetables

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churchhaze

Well-Known Member
OneHitDone said:
In an area where overhead space is limited and your only trying to grow plants to a height of 12-14" are cobs not a good fit due to intensity?
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To design for a lower profile, you should consider cxb3070 or cxb2530 and spread them out, rather than having fewer, but larger cxb3590.

I have a 2'x4' tent with 11x cxb2530 at 500mA and a 2'x4' tent with 12x vero 18 at 700mA. The plants can get pretty close to the light without burning up, compared to a higher powered vero 29 or cxb3590 which needs to be kept much farther away.
 
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CellarDweller

Well-Known Member
churchhaze said:
To design for a lower profile, you should consider cxb3070 or cxb2530 and spread them out, rather than having fewer, but larger cxb3590.

I have a 2'x4' tent with 11x cxb2530 at 500mA and a 2'x4' tent with 12x vero 18 at 700mA. The plants can get pretty close to the light without burning up, compared to a higher powered vero 29 or cxb3590 which needs to be kept much farther away.
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If you are driving CXA COBs at 1400mA, then you need to leave a 20cm gap between COB and canopy otherwise your umol/m2/s will exceed 1500. You won't bleach them (that happens around 18cm) but it means that the plant is receiving more light over 12 hours than midsummers day in Phoenix Arizona (assuming a cloudless day)....EVERY DAY....which is ridiculous! On a 16 hour day, your plants would be receiving more light than is available anywhere on earth.......your choice (I tried it and to be honest, they DO grow).

So I would say you want a height of 20cm or around 9 inches above your maximum canopy height, as long as you have that, then your space should be sufficient.

You could always drive your COBs at a lower mA, which would be more efficient and mean you need more COBs, which gives the added benefit of better distribution......but then you have a higher up-front cost of purchase......but also an ability to position your COBs lower and therefore decrease overhead space whilst maintaining total canopy height.
 
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CellarDweller

Well-Known Member
Fantastic results...... I am currently travelling 14 hours a day and desperately trying to re-pot the plants in spare moments.... Growth is insane at 25 days. Will take photos.
 
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CellarDweller

Well-Known Member
Zucchini fruit growing at an almost alarming rate (5mm thickness and 11mm length overnight!!!) .......I think I will get the first "meal" before day 35......which surely has to be a sign that the plants like the lights?!

Some of the zucchini have been moved outside and the tomatoes will also start being shipped out. Though the current weather conditions are good I have taken some readings and am now trying to come up with a way of explaining to my in-laws that "yes....when it is sunny we get 1700umol/m2/s but then when it is cloudy....it drops to between 15 and 150. Then when it's raining or heavy cloud...you get hardly any red spectrum, which is critical for truly healthy plant growth. My LEDs give a constant 1000 umolm2/s, which is a DLI of 57 mol/m2/d.....blowing the crappy German 17 mol/m2/d at this time of year WAY out of the water....over 3 times more light!"

I somehow do not hold out much hope that the science will be comprehensible. I'll let the plants talk for themselves.
 
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CellarDweller

Well-Known Member
PS - I will also keep a diary of all the fruit weight that is picked from the plants.......am convinced higher DLI and more controlled conditions will produce heavier and healthier fruit.
 
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CellarDweller

Well-Known Member
WOOHOO! My COB holders just ended their RIDICULOUS holiday at the Customs Office.....after 2 freaking weeks! Dammit.

With luck another 2 days and my poor little boys and girls will have a nice spacious new home :) next up on MacGyver's trip down cellar-grown-nutrition.......shelving units :)
 
Tim Fox

Tim Fox

Well-Known Member
i have the artic 11 heat sinks, and if you position the cob holder carefully you can get
Mellodrama said:
Clearly, it does NOT have to be just as I say. Your lights light up when electricity is applied. Who knows how many other folks are growing right now, as we speak, with this poor hardware combination. They may get just as many years of life as a "proper" installation.

I emailed an Ideal rep months ago. He confirmed that all 4 points are supposed to touch down. That's how they designed it.

Things are used outside their design parameters all the time. With varying levels of success.

I tried to get the word out on this subject a while back

https://www.rollitup.org/t/cob-holders-the-basics.805034/

And you're right, I was jumping up & down too much previously. I apologize. I just don't want people thinking that the Ideal holders and the Arctic heatsinks are a great combination. They're a workable combination but not a great one.

You mentioned that installation was easy. Have you closely inspected your work at magnification? Are you sure there are no chips of dirt in between? IMO it's very easy to build a light that you think is getting good thermal contact when it really isn't.

I'd recommend close inspection of every assembly, using some trick like a strong flashlight held behind the COB, to look for any gaps between COB and sink.
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I have the artic 11 heat sinks also, and if you position the cob holders carefully you can get all 4 contact points to hit the flat surface, I suppose some people just dont know leading up to drilling that it is important to have all 4 contacts touching, fortunatly for me I was able to read your post on another thread concerning this very subject, but to ditch the artic 11's all together ? I suppose for those who have not gotten the advice in time, using a differant heat sink with a wider surface would suffice,
 
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CellarDweller

Well-Known Member
Tim Fox said:
i have the artic 11 heat sinks, and if you position the cob holder carefully you can get
I have the artic 11 heat sinks also, and if you position the cob holders carefully you can get all 4 contact points to hit the flat surface, I suppose some people just dont know leading up to drilling that it is important to have all 4 contacts touching, fortunatly for me I was able to read your post on another thread concerning this very subject, but to ditch the artic 11's all together ? I suppose for those who have not gotten the advice in time, using a differant heat sink with a wider surface would suffice,
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Hanging the contact points, as I do in my picture, off the side of the raised surface doesn't mean they are "floating in thin air".....they're in contact with the sloped side of the sink. Is that still a problem? I don't see how....but am willing to understand if it is explained :)
 
Tim Fox

Tim Fox

Well-Known Member
CellarDweller said:
Hanging the contact points, as I do in my picture, off the side of the raised surface doesn't mean they are "floating in thin air".....they're in contact with the sloped side of the sink. Is that still a problem? I don't see how....but am willing to understand if it is explained :)
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from what I understand , and from reading his other posts about the cob holders, is the 4 contact points prevent a person from over tightening the cob down and crushing it, I have seen many people mount the cobs with the holders like yours with less than 4 points of contact and they work fine, just dont be a gorilla on the screw driver, gentle pressure is all that is needed,
 
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CellarDweller

Well-Known Member
The LED holders are just down the road.......by Sunday my farm will be almost ready :)

Now I just gotta start making those damn pots!
 
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