Nope just comparing notesunkle_psycho wrote: ↑Thu Nov 01, 2018 6:09 pmPerhaps the LedG would know, if he passes by. Is there anything specific you need help with?
Basement Salad Garden Build Planning
How many watts per sq/ft did you end up with?
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unkle_psycho
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My salad garden is still on its way, I have a bunch of chilies, tomatoes, salads and herbs growing inside, but I have not finished a dedicated area for them yet.
The recommended DLI for salads and herbs is min. 12mol and optimal 18mol. The number is arrived at by combining light intensity and time, so a more powerful light allows a shorter lights on cycle. This is a key difference compared to the lights people make for growing cannabis, which need high intensity to deliver light in a short 12h window.
My veg area gets 75w/ 4.5 square feet, or 150w / 1m2. My strips are about 7% less efficient then the samsung f-series. My drivers output 75w, so I'm not taking driver loss into account here.
My strip put's out 2.26umol, to get ppf I multiply this with watts: 150x2.26= 339ppf.
Ppfd is a spot measurement, it will show how evenly light spreads out in your space, but we can calculate average PPFD by dividing ppf by m2, Since my area is 1m2, nothing needs to be divided, I get an average ppfd of 339. If my space was half, my averadge PPFD would be double etc.
To calculate the DLI I multiply the ppfd by seconds and divide by 1 million. I will calculate the value for one hour:
339x3600/1000000= 1.22mol. An 18/6 cycle will give about 22mol. I run my veg area 24/7 so the plants end up with 30mol, which is the recommended level for tomatoes and chilies.
This is using about 18w/ square foot. I imagine 10w would be quite acceptable if using more efficient leds and having a long lights on cycle.
What leds are you using, and how long do you run lights on?
The recommended DLI for salads and herbs is min. 12mol and optimal 18mol. The number is arrived at by combining light intensity and time, so a more powerful light allows a shorter lights on cycle. This is a key difference compared to the lights people make for growing cannabis, which need high intensity to deliver light in a short 12h window.
My veg area gets 75w/ 4.5 square feet, or 150w / 1m2. My strips are about 7% less efficient then the samsung f-series. My drivers output 75w, so I'm not taking driver loss into account here.
My strip put's out 2.26umol, to get ppf I multiply this with watts: 150x2.26= 339ppf.
Ppfd is a spot measurement, it will show how evenly light spreads out in your space, but we can calculate average PPFD by dividing ppf by m2, Since my area is 1m2, nothing needs to be divided, I get an average ppfd of 339. If my space was half, my averadge PPFD would be double etc.
To calculate the DLI I multiply the ppfd by seconds and divide by 1 million. I will calculate the value for one hour:
339x3600/1000000= 1.22mol. An 18/6 cycle will give about 22mol. I run my veg area 24/7 so the plants end up with 30mol, which is the recommended level for tomatoes and chilies.
This is using about 18w/ square foot. I imagine 10w would be quite acceptable if using more efficient leds and having a long lights on cycle.
What leds are you using, and how long do you run lights on?
"Nothing is true, everything is permitted"
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unkle_psycho
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I just bumpped into an interesting video on this intensity subject. They are doing tests on lettuce to test different lighting intensity/ time ratios. The light is too much for all of them, so it should be noted that some other salads and herbs would not mind this light intensity.
"Nothing is true, everything is permitted"
Im on the fence whether or not to buy a Li-Cor sensor. Giving me full control and really being able to dial my grows in. I well understand PPF, PPFD, and DLI and I very much appreciate the way you layed those calculations out in an easy to read way. That being said, I choose not to get wrapped up in all those calculations. Because that's naturally how I am, and I will literally get wrapped up in them. I've done it with hobbies in the past where my analytical side takes over and I tend to lose sight of my end game, getting bogged down in mathematics that aren't recordable. That's just me personally.unkle_psycho wrote: ↑Sat Nov 03, 2018 10:05 amWhat leds are you using, and how long do you run lights on?
I'm trying to decide which sensor is best for me. Also wondering if the dang things ever go on sale!!!
Currently im using Eb gen2. 1' and 2' strips. Also have a stack of F series but haven't been able to commit on how I want to incorporate those.
Vesta's are now the focus of my next build.
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unkle_psycho
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I would love to get one of those sensors, but for the moment I can't justify it... I have been growing since the 90's, and the way I see it modern strip builds are finally starting to match predicted spreadsheet performance, since they do such a good job spreading the light evenly. This is just an observation from following builds in forums though...
It seems to me that the main calibration strip builders use their PAR meters for is to reduce strip distance slightly towards the sides and spread them a little in the center to avoid the hotspot. I think QB's still try to copy a HID footprint so more measurement is needed to get them right.
I do plan on doing side by sides on all my strains at all grow stages to really see how they react to different environments.
I certainly have got a little carried away on the calculations. This summer was unusually hot in scandinavia, and I got to do a side by side where one plant was in a greenhouse with 8h of light, and another was in a prime spot with about 12h of direct light. The plant in the greenhouse grew and produced double. This started me on a long path questioning the value I had given lighting in growing. I found VPD charts and started to understand what I was missing. I had thought greenhouses were just for temperature.
Anyway, I guess there are not too many par meters on the ssecond hand market... I was so lucky I got a co2 meter from someone who stopped growing. They needed money asap and sold it to me for 50e. It would have been 300e new.
When I was looking at those PAR meters I was wondering if it would not make more sense to get a lumen meter? To my best understanding the PAR meter still needs to be weighted to the maccree curve, and if you know the conversion factor you could calculate everything from LUX just the same? Did I understand something wrong?
It seems to me that the main calibration strip builders use their PAR meters for is to reduce strip distance slightly towards the sides and spread them a little in the center to avoid the hotspot. I think QB's still try to copy a HID footprint so more measurement is needed to get them right.
I do plan on doing side by sides on all my strains at all grow stages to really see how they react to different environments.
I certainly have got a little carried away on the calculations. This summer was unusually hot in scandinavia, and I got to do a side by side where one plant was in a greenhouse with 8h of light, and another was in a prime spot with about 12h of direct light. The plant in the greenhouse grew and produced double. This started me on a long path questioning the value I had given lighting in growing. I found VPD charts and started to understand what I was missing. I had thought greenhouses were just for temperature.
Anyway, I guess there are not too many par meters on the ssecond hand market... I was so lucky I got a co2 meter from someone who stopped growing. They needed money asap and sold it to me for 50e. It would have been 300e new.
When I was looking at those PAR meters I was wondering if it would not make more sense to get a lumen meter? To my best understanding the PAR meter still needs to be weighted to the maccree curve, and if you know the conversion factor you could calculate everything from LUX just the same? Did I understand something wrong?
"Nothing is true, everything is permitted"
Sorry guys, got busy with life, haha. Ended up doing 6 x 22" strips (F-series 22" F562B) running at ~80% max current (powered with a HLG-240H-24A) and hanging 8-10" above canopy for a 8x2' area. Worked out great for a budget build that's capable of growing strawberries and short leafy greens in a small space. Not sure I would change anything - maybe add another strip for more even coverage? You can see my progress on growing strawberries with these lights here: https://growingfruit.org/t/growing-stra ... nics/18667
I just use aluminum U channels from Home depot and stuck the strips on with thermal tape (or whatever its called). Running a F-series 22" F562B @ ~80% max current in a 65°F basement with absolutely no airflow they get very warm but not hot (maybe 130°F?). With just a small fan to move some air they stay comfortably warm.EddyNoMuscle wrote: ↑Mon Jun 11, 2018 7:00 pmI like the LT-F562B a lot but... How do you manage heat? Do these strips require a "true" heatsink? I can't find much info on heat management! Don't they require to dissipate something like 17W of heat?