All COB Users - Lettuce Grow Challenge!!

Patrick N. said:

Hi guys. Newbie here. Muleface, where did you get your tubes for $6 each? The lowest price I've seen so far is $10/tube (ebay). Thanks so much.

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you have to order them from china directly. They about $6 a piece of you order a case of 50 of them.

check alibaba, ill see if i can find the specific vendor for them. if you haven't ordered from alibaba before, its interesting.

muleface said:

you have to order them from china directly. They about $6 a piece of you order a case of 50 of them.

check alibaba, ill see if i can find the specific vendor for them. if you haven't ordered from alibaba before, its interesting.

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Thanks Muleface, that'd be awesome. I found some 6000-6500k 22w LED tubes from DHGate for about $4-5/each. Are you running these types of lights or the purple/blue/red led tubes? Would I be able to veg on 6000k? These vendors give a range and I'm not sure if its really 6500k or 6000k. Thanks.

Patrick N. said:

Thanks Muleface, that'd be awesome. I found some 6000-6500k 22w LED tubes from DHGate for about $4-5/each. Are you running these types of lights or the purple/blue/red led tubes? Would I be able to veg on 6000k? These vendors give a range and I'm not sure if its really 6500k or 6000k. Thanks.

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I am running 6-6.5k lights. Not sure about the exact spectrum. But its close enough for what i'm doing. The lights are just white, there is no mix of different colors. I wasn't aware of DHgate, but it looks like someone took alibaba and made it easier to use. If you can get them for 4-5 each, that would be the route to go. I looked around their site, it looks like this is what I have :

http://www.dhgate.com/product/1ft-6w-2ft-3ft-t5-led-tube-lights-4ft-22w/256933363.html#s1-11-7b;searl|3704386583

They appear to be a bit cheaper price wise then what i paid. Alibaba is kind of hit and miss, they will quote you a price, then if you bitch a bit about it, they will somehow find a better shippping rate. its like magic, but with dhgate it looks like shipping is built in. So good find, and also burn in hell, this site will be the death of me!!

happy growing

Mule

muleface said:

I am running 6-6.5k lights. Not sure about the exact spectrum. But its close enough for what i'm doing. The lights are just white, there is no mix of different colors. I wasn't aware of DHgate, but it looks like someone took alibaba and made it easier to use. If you can get them for 4-5 each, that would be the route to go. I looked around their site, it looks like this is what I have :

http://www.dhgate.com/product/1ft-6w-2ft-3ft-t5-led-tube-lights-4ft-22w/256933363.html#s1-11-7b;searl|3704386583

They appear to be a bit cheaper price wise then what i paid. Alibaba is kind of hit and miss, they will quote you a price, then if you bitch a bit about it, they will somehow find a better shippping rate. its like magic, but with dhgate it looks like shipping is built in. So good find, and also burn in hell, this site will be the death of me!!

happy growing

Mule

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Sorry about DHgate. I was surprised by their prices also. I was about to pay double for T8s from another site and build my own holders. These T5s seem much easier (plug and play-ish). How many T5s do you mount together for a growing space? Do you just splice these with say an old computer power cord and just plug it in?

muleface said:

I am running 6-6.5k lights. Not sure about the exact spectrum. But its close enough for what i'm doing. The lights are just white, there is no mix of different colors. I wasn't aware of DHgate, but it looks like someone took alibaba and made it easier to use. If you can get them for 4-5 each, that would be the route to go. I looked around their site, it looks like this is what I have :

http://www.dhgate.com/product/1ft-6w-2ft-3ft-t5-led-tube-lights-4ft-22w/256933363.html#s1-11-7b;searl|3704386583

They appear to be a bit cheaper price wise then what i paid. Alibaba is kind of hit and miss, they will quote you a price, then if you bitch a bit about it, they will somehow find a better shippping rate. its like magic, but with dhgate it looks like shipping is built in. So good find, and also burn in hell, this site will be the death of me!!

happy growing

Mule

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Are you running your tubes with the lens cover on or off? Clear or Frosted?

Patrick N. said:

Sorry about DHgate. I was surprised by their prices also. I was about to pay double for T8s from another site and build my own holders. These T5s seem much easier (plug and play-ish). How many T5s do you mount together for a growing space? Do you just splice these with say an old computer power cord and just plug it in?

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so they come (at least mine did) with wonky wires, they don't have plugs on them. Its one side fits into the light, the other is bare copper. so, if you look on ebay you can find power cords and short daisy chain wires for them.

http://www.ebay.com/itm/10-25Pcs-1ft-Extension-Cable-Connector-Wire-For-T5-T8-Integrated-Led-Tube-Light-/172253249803?var=&hash=item281b18010b:m:mLM2NOtQcAi7k2FAezkNoBQ
http://www.ebay.com/itm/10PK-AC-Power-Cord-with-3-terminal-female-plug-for-T5-T8-Integrated-Tube-Lights-/182426845437?hash=item2a797cc0fd:g:CHsAAOSw2xRYgwzW

the above links are just examples of what you need, or might need. you can probably find a better price on them. They sell cords with switches on them, they are absolute garbage. I would recommend avoiding them. They for whatever reason don't totally cut off the power, so a little still bleeds in, it at some point would fry the already low end driver on the lights.

I have a 4x8 space, i'm running 28 of these lights there. This gives me 19.25 watts per sf, which is a bit high for lettuce. you could probably get away with 22 lights. side note, the manufacturer told me that he doesn't recommend wiring any more then 4 of them in series. I have wired more, and it works fine, but if the guy making them tells me 4, ill trust him. ONLY DO 4!

OneHitDone said:

Are you running your tubes with the lens cover on or off? Clear or Frosted?

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had clear covers, removed them, now i don't run any cover at all.

ok, as I stated earlier the Organic Nitrogen was a flop so I swapped it out with a different nutrient and lookie here - A nice crop of lettuce about ready for harvest



First run on the wall NFT fell victim to major tip burn so was scrapped. Once the next seedlings are ready to go we will try it again at a lower dosage

My harvest has began....My tip burn seems pretty minimal. Most plants don't have any at all. I should be to the point where i won't need to buy lettuce for quite some time. There are around 60 heads here, of a variety of types. I just walk around and clip large leaves and add them to my bowl. My wife finally has gotten rewarded for her patience. I don't think she thought there was ever going be anything from this.

The cheapo lights really did well. Not sure if i used something else if it would have worked better. But for $168 to cover a 4x8 with LED, I think it can't be beat.

OneHitDone said:

ok, as I stated earlier the Organic Nitrogen was a flop so I swapped it out with a different nutrient and lookie here - A nice crop of lettuce about ready for harvest

View attachment 3886001 View attachment 3886002

First run on the wall NFT fell victim to major tip burn so was scrapped. Once the next seedlings are ready to go we will try it again at a lower dosage
View attachment 3886003 View attachment 3886004

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keep on documenting your nitrogen trials. I would like to see where this goes.

Thanks for the link, gonna order some led strip lights for my garage, thinking about these.... http://www.dhgate.com/product/double-row-led-t8-tube-4ft-28w-8ft-72w-7200lm/385765616.html?recinfo=8,103,6#cppd-6-5|null:103:r1615779073
Maybe Ill even have a few left over for my indoor plants!

last set of lettuce pics....promise.

They are all about a week apart from each other.

muleface said:

last set of lettuce pics....promise.

They are all about a week apart from each other.

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looks good, you measure lux at the plant level to see what kind of light intensity they are getting? Im curious.... There are free apps for most smartphones that do this.

it was 250 at the base of the plants, when i started. Then i moved it up when they started to grow. I pull a reading when i get home and update this post.

What do you guys use in tight spaces (like stacked rows) of lettuce growing other than T5s? I'm mainly growing loose leaf type lettuce like black seeded simpson , thanks.

Yodaweed said:

What do you guys use in tight spaces (like stacked rows) of lettuce growing other than T5s? I'm mainly growing loose leaf type lettuce like black seeded simpson , thanks.

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Stuff like Bridgelux EB or similar light engines like http://www.samsung.com/global/business/led/products/led-engine/ambient-light-engine/h-series-gen3

Or low powered (under 10w) cobs on a very low profile heatsink like an aluminum baking sheet / high power led diodes.

Or t8/t5 led tubes

frica said:

Stuff like Bridgelux EB or similar light engines like http://www.samsung.com/global/business/led/products/led-engine/ambient-light-engine/h-series-gen3

Or low powered (under 10w) cobs on a very low profile heatsink like an aluminum baking sheet / high power led diodes.

Or t8/t5 led tubes

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This is what is still being worked out hopefully in this thread.
We have seen many not so great led lettuce plants and a few so so.
I plan to start putting up some cash and trying a few different led options again myself very soon.
I am dying to see field / greenhouse grown size and quality produce under led

OneHitDone said:

This is what is still being worked out hopefully in this thread.
We have seen many not so great led lettuce plants and a few so so.
I plan to start putting up some cash and trying a few different led options again myself very soon.
I am dying to see field / greenhouse grown size and quality produce under led

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Yea i hear ya, i am also looking for equipment that is proven to grow quality produce. my t5's seem to work well just looking to use less electric but i don't want to waste money and time and from my cannabis growing experience LEDs aren't that great.

frica said:

Stuff like Bridgelux EB or similar light engines like http://www.samsung.com/global/business/led/products/led-engine/ambient-light-engine/h-series-gen3

Or low powered (under 10w) cobs on a very low profile heatsink like an aluminum baking sheet / high power led diodes.

Or t8/t5 led tubes

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I'm a really thrilled with my cheap'o LED lights. They worked great, well, aside from the bib lettuce i grew, it had some leaf burn, but I can't say if the issue is with the lights or nutrients...or both...

I'm at the point where my lettuce is growing so fast, i can't keep up eating it. I put 60 heads in my grow area, but I be just fine with 20.

I know this forum was originally designed for COB growing, but, i think if you used 6500k cobs, and spread the lights out and did a nice even coverage at maybe 15-20 watts a sf, you would get great results.

I did grow some lettuce under some 3k cobs, it grew just fine. It was a bit thicker in the leafs then I would have liked it, it also seemed to spread out more then it growing upward, which was odd.

***caution, opinion of mine, not suitable for all****

I have no doubt that cobs can be used in this application, but I'm starting to think cobs, while great, might turn out to be a passing fad. You either need a lot of them, or need to run them harder. The total cost just doesn't do it for me. You grab a vero 29 for $25, then you need a $25 heat sink (for passive). That gets you to $50 a light. Now you have to create an elaborate frame for them Its not a crazy expensive investment, I think i pay $12 for a 10 foot angle bar. so for a six light fixture, you need 4 - 10 foot bars, so $50 more. That gets you up to $350. But you still need a driver(s), cob holders, reflectors/lenses (if that's your thing) wago connectors, wire, etc. you might be looking at $450-$500 for a 6 cob fixture covering a 4x4.

I mean yeah, you could get cheap drivers, cheap cobs, small heat sinks with active cooling. and just hang them from the top of your tent. you could drop the cost down by half or more doing it that way, but no label drivers pushing a lot of current concerns me.

I think the next phase here is going to be the rigid led strips or quantum boards (or a combo of them both). Dump the big heat sinks, slim down the frame, create better coverage.

with that said, i haven't tested the strips yet, i have them sitting in a box a waiting my next build. I could be totally wrong on this, however my lettuce patch has done amazing. It its basically just rigid strips, albeit cheap ones, but rigid strips none the less.

Im actually looking at getting some more cheap integrated lights in the 3k to 3.5k range. I can make a 4x4 for under $200.

anyway, i still would like to see someone do a full cob lettuce build.

muleface said:

I'm a really thrilled with my cheap'o LED lights. They worked great, well, aside from the bib lettuce i grew, it had some leaf burn, but I can't say if the issue is with the lights or nutrients...or both...

I'm at the point where my lettuce is growing so fast, i can't keep up eating it. I put 60 heads in my grow area, but I be just fine with 20.

I know this forum was originally designed for COB growing, but, i think if you used 6500k cobs, and spread the lights out and did a nice even coverage at maybe 15-20 watts a sf, you would get great results.

I did grow some lettuce under some 3k cobs, it grew just fine. It was a bit thicker in the leafs then I would have liked it, it also seemed to spread out more then it growing upward, which was odd.

***caution, opinion of mine, not suitable for all****

I have no doubt that cobs can be used in this application, but I'm starting to think cobs, while great, might turn out to be a passing fad. You either need a lot of them, or need to run them harder. The total cost just doesn't do it for me. You grab a vero 29 for $25, then you need a $25 heat sink (for passive). That gets you to $50 a light. Now you have to create an elaborate frame for them Its not a crazy expensive investment, I think i pay $12 for a 10 foot angle bar. so for a six light fixture, you need 4 - 10 foot bars, so $50 more. That gets you up to $350. But you still need a driver(s), cob holders, reflectors/lenses (if that's your thing) wago connectors, wire, etc. you might be looking at $450-$500 for a 6 cob fixture covering a 4x4.

I mean yeah, you could get cheap drivers, cheap cobs, small heat sinks with active cooling. and just hang them from the top of your tent. you could drop the cost down by half or more doing it that way, but no label drivers pushing a lot of current concerns me.

I think the next phase here is going to be the rigid led strips or quantum boards (or a combo of them both). Dump the big heat sinks, slim down the frame, create better coverage.

with that said, i haven't tested the strips yet, i have them sitting in a box a waiting my next build. I could be totally wrong on this, however my lettuce patch has done amazing. It its basically just rigid strips, albeit cheap ones, but rigid strips none the less.

Im actually looking at getting some more cheap integrated lights in the 3k to 3.5k range. I can make a 4x4 for under $200.

anyway, i still would like to see someone do a full cob lettuce build.

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Please try some bib again, I would be very interested to see just how nice you can get your heads looking under the "cheap tubes"

muleface said:

so my water is already at about .5 or .6 out of tap. Id think if i only added .5 more in nutrients they would be malnourished.

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Hey man i've been growing lettuce kratky method with the 4-18-38/calcium nitrate/magnesium sulfate mix in full sun for years with incredible results, my tap water EC is around 0.45 and i mix 12g/12g/6g per 5 gallons of tap water, my tap water has a ph of 7.5 and the fertilizers drop it to about 6.5/6.6, i usually dont bother playing with the ph at all for lettuce.

i'd post a picture but i cant yet..