All COB Users - Lettuce Grow Challenge!!

frica

Well-Known Member
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
Probably a colour temp issue.
 

OneHitDone

Well-Known Member
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..
They are still working on the photo uploader after the site hack. Please do share pics once it's back up and running
 

frica

Well-Known Member
What is you opinion on the "magic" led color temp for lettuce?
Something blue heavy.
Too much red gives peculiar growth, even if it does increase biomass.

5000-6500k, something closer to sunlight.

Or blurple*, which are already in use in commercial greenhouses.
http://www.lighting.philips.com/main/cases/cases/horticulture/osaka.html
Philips recommends their blue+far red bars for leafy greens and herb, don't know the ratio though.


*inb4 haters, but green photosynthesis rate is lower in leafy greens than something like evergreen trees or marijuana, and blue/far red diodes are simply more efficient than any phosphor based whites and greens leds are way less efficient than blue.


Looking through philips case studies, there are also images of white/whitish lighting with lettuce under it.
 
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eyderbuddy

Well-Known Member
Hey guys, long time no post. I completelly forgot to post my progress in this thread, and RIU died so there's that.
Short story:

Bought a bag of cheap coco and most of what i tried to grow died because it was too dirty. Fun fact is that the lettuce didn't die, it definitely grew at half the normal pace, but it grew! I used 2 Citis 1212 [3500k 80] @ 50W

Link to album (since RIU isn't reliable for pics anymore):
http://imgur.com/a/CCUl1

After everything died i just grew teh herbz becuz
 
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Yodaweed

Well-Known Member
Something blue heavy.
Too much red gives peculiar growth, even if it does increase biomass.

5000-6500k, something closer to sunlight.

Or blurple*, which are already in use in commercial greenhouses.
http://www.lighting.philips.com/main/cases/cases/horticulture/osaka.html
Philips recommends their blue+far red bars for leafy greens and herb, don't know the ratio though.


*inb4 haters, but green photosynthesis rate is lower in leafy greens than something like evergreen trees or marijuana, and blue/far red diodes are simply more efficient than any phosphor based whites and greens leds are way less efficient than blue.


Looking through philips case studies, there are also images of white/whitish lighting with lettuce under it.
Sweet i got some old blurple LEDs i can recycle, i got my lettuce seeds above ground right now, gonna transplant tomorrow, what sized containers is best? I was figuring 3 gal fabric pots.
 

muleface

Well-Known Member
Sweet i got some old blurple LEDs i can recycle, i got my lettuce seeds above ground right now, gonna transplant tomorrow, what sized containers is best? I was figuring 3 gal fabric pots.
it depends on big you wanna let them go. A 3 gallon put would be fine i suppose, but i think you would be better served with much smaller pots and more of them. Lettuce doesn't take up much root space really. Its not like tomatoes. A 1 gallon pot would be more the suitable, maybe even a half gallon pot. The only issue would see if you would need to keep them watered more often.

also, glad we are back!
 

thetr33man

Well-Known Member
They are in sunshine bx with a thin layer of super soil on the bottom, just about 1/2 to 1 inch. Watered with just rain water. Starting to get some tip burn on inside leaves, I think not enough air movement as they get denser. I harvesed a bunch of the plain green stuff yesterday to thin it out a bit.
 

muleface

Well-Known Member
forgive me, im on a plane and bored....there may be rambling...

So my lettuce project is going to start winding down. I realized that 60 heads of lettuce, while looking cool, is too much for 2 adults and a child to eat. perhaps 20 would be better.....

what I have learned.

1. cheap integrated leds from alibaba work great for lettuce. I had mine in the 6500k range. I am at about 19w per sf. which seems just fine, you could probably get by with a little less, maybe 15-19 would be fine....

2. NFT channels also work great. I would recommend them (check out farmtek, they are pretty reasonable)

3. Use a LARGE LARGE tank of water. mine is 110 gallons. It keeps the PH and EC very consistent.

4. I just used regular dry nutrients made for growing tomatoes and dry cal/mag. It worked great. No need for special lettuce mix, or needs for crazy expensive liquids. $175 got me 5500 gallons of mix.

5. Get a good air pump. I got one on amazon for maybe $50, it works great.

6. use your 110 gallon tank to water/feed other things at the same time. This does 2 things. 1. you can grow other things from 1 tub 2. its slowly drains the tank over a week or so. so you don't need to adjust nutrients. You just refill it and add new nutrients.

7. get a good root structure before you move to NFT channels. I let mine germinate for almost a month. @OneHitDone suggested that i put my rockwool cubes over perlite and/or vermiculite. It worked great, i highly recommend it. when you are ready to transplant, just drench the entire area and GENTLY remove the rockwool cubes. You'll have great roots.

8. Bib lettuce did not do well in my setup, however everything else did. its was odd

9. Grow a lot of different varieties on your first run. some stuff will do better then others.

10. document your work, we would like to see it.
 

OneHitDone

Well-Known Member
forgive me, im on a plane and bored....there may be rambling...

So my lettuce project is going to start winding down. I realized that 60 heads of lettuce, while looking cool, is too much for 2 adults and a child to eat. perhaps 20 would be better.....

what I have learned.

1. cheap integrated leds from alibaba work great for lettuce. I had mine in the 6500k range. I am at about 19w per sf. which seems just fine, you could probably get by with a little less, maybe 15-19 would be fine....

2. NFT channels also work great. I would recommend them (check out farmtek, they are pretty reasonable)

3. Use a LARGE LARGE tank of water. mine is 110 gallons. It keeps the PH and EC very consistent.

4. I just used regular dry nutrients made for growing tomatoes and dry cal/mag. It worked great. No need for special lettuce mix, or needs for crazy expensive liquids. $175 got me 5500 gallons of mix.

5. Get a good air pump. I got one on amazon for maybe $50, it works great.

6. use your 110 gallon tank to water/feed other things at the same time. This does 2 things. 1. you can grow other things from 1 tub 2. its slowly drains the tank over a week or so. so you don't need to adjust nutrients. You just refill it and add new nutrients.

7. get a good root structure before you move to NFT channels. I let mine germinate for almost a month. @OneHitDone suggested that i put my rockwool cubes over perlite and/or vermiculite. It worked great, i highly recommend it. when you are ready to transplant, just drench the entire area and GENTLY remove the rockwool cubes. You'll have great roots.

8. Bib lettuce did not do well in my setup, however everything else did. its was odd

9. Grow a lot of different varieties on your first run. some stuff will do better then others.

10. document your work, we would like to see it.
#8?
What in the end was the problem that the bib lettuce was suffering?
 

MediheaLed

Well-Known Member
This while run is my first attemp in over a year of growing - new equipment new house and I hadn't grown much before so it looks like I fucked some of it up... but here ya go

View attachment 3882226
Super nice idea and very clean! My kids would love even a two foot shelf to grow what ever random bean plants from school. They want to be like daddy! I realize this is a work in progress, and I'm sure you already did something about it but that power strip on the floor beneath all that water made me uncomfortable. You could zip tie to the side of your rack, on the shelf or on the legs. Even under a rack with plugs facing the floor. Thank you.
 

muleface

Well-Known Member
#8?
What in the end was the problem that the bib lettuce was suffering?
I'm not really sure, maybe the light, maybe the nutrients. maybe both...It grew kind of weird, it also shot to see really quickly.

My current crop is starting to die. once things go south, they go quickly. I suppose I have to consider the fact I put the seeds in the rockwool for this run on Dec 15th. So around 80 days. I'm not sure how long lettuce is suppose to really last, but 80 days seems like a long time.

There is the also the consideration that I had so much lettuce that I wasn't really able to do much with most of it. 60 or so heads, so some/most of it never even got trimmed down, some heads that were smaller got buried under the larger neighbors. I think when i do this again, i would do 10 heads wait 2 weeks, 10 more, wait 2 weeks, then 10 more. I would really spread them out over my grow area, and let them get all the light they need. maybe even just do 7 per cycle. for a total of 21. I think for 3 people, that is more then enough.

I would like to see how things would grow if i was able to properly trim them.

The second photo is my tomato patch, there were other plants too in there, but they did not survive the tomato onslaught. As a side note, all the large plants came from clipping from one plant I had in my outside garden last year. They survived my terrible outdoor hack job, and even survived my aeroponics attempt (that was a dark chapter). once I put them in coco they went crazy. I'm a huge coco fan, specifically canna.
 

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