Seedling PPFD and DLI? Autos
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garybo
Well-Known Member
Wow, that is a range. Personally I grow outdoor if that means anything. I take my seedlings and put them outside with a quart jar over them to keep the bugs off. Their light range is usually around 10 hours. Being in the summer, I leave them out all night with the jar over them.
After a week, the jar comes off.
Looking forward to seeing what the experts here have to say and their opinion.
Nice question.
Delps8
Well-Known Member
Yeh, 12 mols to 30 is a pretty wide range.
I've gone from low DLI's (12) to my current approach of getting seedlings to a DLI of 25 and then ramping up to and maintaining as close to 58 mols as possible.
You mention DLI - how are you measuring DLI? Have you checked with the manufacturer of your light for that information?
Listersmeghead
Well-Known Member
I've got 3 auto seedlings on day 3 .
They're sitting under about 200 ppfd at the moment and loving it.
I use a lux meter then convert using ×0.017 for par.
I started the seedlings at 10.000 lux, they asked for more light...so raised to 12.000 lux and now the leaves are praying.
My light schedule is 18/6
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- #5
25 wow! That is double what I was using for reference. I assume they are loving it?
I'm using the photone app.
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- #6
Thanks so that is 13 for DLI.
Listersmeghead
Well-Known Member
No worries.
I've never worked out DLI...I just go by what has worked in the past. Usually by day 28 I match the lux by the age of the plant... day 35 - 35k lux, day 45- 45k lux ....etc.
With autos I stay under 50k lux even fully flowering.
I've never measured lux and not bothered to find out what ppfd, ec, ppm, dli and all that stuff even means
Light, bit of water, fresh air - as long as it's green, I'm happy
Light, bit of water, fresh air - as long as it's green, I'm happy
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- #9
I wish my brain worked like that! I'm sure a therapist would have something to say about how obsessive I get in the research phase of hobbies!
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- #10
Thanks! That seems to roughly line up with the guidelines I've seen on a few charts.
Day 28 your DLI is 31
Day 35 your DLI 39
A man with two watches doesn't really know what time it is any better than a man with none
All the stuff I don't measure never bothers me
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- #12
No doubt! Hopefully I'll get there somedayA man with two watches doesn't really know what time it is any better than a man with none
All the stuff I don't measure never bothers me
garybo
Well-Known Member
I'm under the impression an active brain will produce a healthy mind, I'm no therapist though..
Delps8
Well-Known Member
Praying leaves is a very good sign. I've seen it in early veg but not later than that, despite light levels ≈ 900 µmols.
Delps8
Well-Known Member
Yes, the grow turned out quite well but 25 DLI for seedlings was just a piece of it.
If I was using Photone, I would first try to calibrate it against a known good source (grab the "Clear Sky" app from the iPhone App Store). After that, I would set my lights to 900 µmols and then watch for an adverse reaction. If the plants tolerated 900 µmols well, increase it by 50 µmols (or some other small increment) and see how things go.
If you see signs of light avoidance (leaves rotating around their horizontal axis, canoing/tacoing, or curling leaf margins) or light damage (bleaching of the leaves), reduce you light levels.
Lather, rinse, repeat.
Per the attachment, light is just one variable in the growing equation. If you're going to feed your plants a lot of light, you need to get the other variables up to snuff.
Delps8
Well-Known Member
That's because the folks at GLM are quoting other industry sources.Thanks! That seems to roughly line up with the guidelines I've seen on a few charts.
Day 28 your DLI is 31
Day 35 your DLI 39
I've tested Korona/Photone twice and, during that process, I've traded emails with their programmer (I've been writing software professionally for 30± years so I have some insight into the issues that he's dealing with). When I asked him about the source for that chart, he replied that they're using the sources cited on their site. Thus, it's not research that they've done. I'm not knocking that in the least (that's actually wise on their part) but it's good to know the provenance of data that's being presented.
I brought up the point that it looked like this was for photos and he agreed. In short, his recommendation for autos was a DLI of 45 mols as soon as plants can handle it.
Those are standard light levels and you'll get a good crop, assuming the rest of the environment is sound. OTOH, industry research show increasing net photosynthesis to top out at ≈ 900 µmols in non-CO2 environments. My experience and the experience of other growers here on 420 has been very positive with PPFD's that high.
I just finished a two plant Gorilla Glue grow (autos) and the yield was 26 ounces. For whatever reason, for the last two grows, I've had one plant dominate the other plant(s) in the tent. It happened with Gelato autos and also with my GG autos. For my more recent grow, it looked like Chris was taking up about 80% of the tent leaving Wilma at 20%. When everything was cut and dried, that ratio held. Chris yielded 20 ounces, Wilma yielded 5. Granted, that's only one trial that I've done at the light saturation point but it mirrors peer reviewed research from a number of sources.
I also looked at the increase in electricity cost and found it to be negligible, even at the insane rates that we pay for electricity in Southern California. The delta between "regular" light levels and 900'ish works out to less than $20 per month. My thinking on that point - if I drop my wattage by 100 watts, PPFD will fall from 1000 to 670 and those 100 watts = 54 kWh @ 30¢ each = not a lot.
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- #17
I hope so..!
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- #18
That's because the folks at GLM are quoting other industry sources.
I've tested Korona/Photone twice and, during that process, I've traded emails with their programmer (I've been writing software professionally for 30± years so I have some insight into the issues that he's dealing with). When I asked him about the source for that chart, he replied that they're using the sources cited on their site. Thus, it's not research that they've done. I'm not knocking that in the least (that's actually wise on their part) but it's good to know the provenance of data that's being presented.
I brought up the point that it looked like this was for photos and he agreed. In short, his recommendation for autos was a DLI of 45 mols as soon as plants can handle it.
Those are standard light levels and you'll get a good crop, assuming the rest of the environment is sound. OTOH, industry research show increasing net photosynthesis to top out at ≈ 900 µmols in non-CO2 environments. My experience and the experience of other growers here on 420 has been very positive with PPFD's that high.
I just finished a two plant Gorilla Glue grow (autos) and the yield was 26 ounces. For whatever reason, for the last two grows, I've had one plant dominate the other plant(s) in the tent. It happened with Gelato autos and also with my GG autos. For my more recent grow, it looked like Chris was taking up about 80% of the tent leaving Wilma at 20%. When everything was cut and dried, that ratio held. Chris yielded 20 ounces, Wilma yielded 5. Granted, that's only one trial that I've done at the light saturation point but it mirrors peer reviewed research from a number of sources.
I also looked at the increase in electricity cost and found it to be negligible, even at the insane rates that we pay for electricity in Southern California. The delta between "regular" light levels and 900'ish works out to less than $20 per month. My thinking on that point - if I drop my wattage by 100 watts, PPFD will fall from 1000 to 670 and those 100 watts = 54 kWh @ 30¢ each = not a lot.
Thanks I really appreciate you typing out all of this. I'm a big fan of numbers when it comes to things like this. I just found your posts on the Autoflowers site too and watched the Debacco vids. It makes a lot of sense. I'll be ramping my own setup as soon as my environment is totally sorted, waiting on a humidifier.
One of the things he mentioned in a vid was about water limitations. I assume he is talking about watering frequency. You grow Hydro right? are you running increased nutrients vs the norm?
I wonder what the correct watering schedule for soil is at higher PPFD's? That is tonights task I think.
Delps8
Well-Known Member
Thanks I really appreciate you typing out all of this. I'm a big fan of numbers when it comes to things like this. I just found your posts on the Autoflowers site too and watched the Debacco vids. It makes a lot of sense. I'll be ramping my own setup as soon as my environment is totally sorted, waiting on a humidifier.
One of the things he mentioned in a vid was about water limitations. I assume he is talking about watering frequency. You grow Hydro right? are you running increased nutrients vs the norm?
I wonder what the correct watering schedule for soil is at higher PPFD's? That is tonights task I think.
DeBacco is a "good read" - he's got just the right tone (informative but not authoritative) and he presents the info in just the right way. These graphics convinced me to take full advantage of my lights. I'd seen his videos, the videos by Bugbee, and read Chandra a few times so I knew that the approach was valid but it took a while for me to go all in.
Re. scaling up - only as needed. I caught a video that Bugbee did and I'm thinking it was for the Cornell Ag school. He was asked about ramping up DLI and, paraphrasing, the said there's no need for that. Plants are "ready to get to work as soon as they jump out of bed" and, in terms of going from 400 - 1200 (CO2) he said that's something that can safely be done in a couple (two) days.
Re. VPD - my guiding light. I use a PulseOne and for almost all of this last grow, I was able to keep VPD at the recommended values. Pulse recommends 0.8 for seedlings, 1.0 for veg, and 1.4 for flower.
Re water - hydro, yes. Big damned bucket. It's a SuperPonics 12 XL (I bought expertise) which is a 35 gallon res that holds 28 gallons of nutes and that has its own set of challenges in that it behaves very differently than a normal 5 or 7 gallon bucket so much of the traditional hydro issues and advice just don't apply. :-(
I suspect DeBacco is talking about watering the plant ("fertigation"?) I don't get the sense that hydro gets a lot of attention from researchers.
Re. nute levels - I start at ⅓ (I'd have to check) and gradually ramp up. I think the highest EC I got was about 1.6 but, when water uptake skyrocketed, I was adding so much RO (a practice I quickly changed) that my EC fell to 1.3±. I had no concern about the drop from 1.6 to 1.3 since those levels appeared be accomplishing the desired goal of providing nutrients - to keep the plants in the "sufficiency" range. As I see it, "pushing nutes" on plants is like shooting pool with a rope (hat tip to George Burns for his comment having sex at age 90) - try as you might, nothing's going to happen and the longer you try, the more frustrated you'll get.
Nutrients aren't that big an issue for me. Nutes are not food. They're analogous to vitamins and minerals for humans and, as we know from studying nutrition, we don't need much in the way of vitamins and minerals to thrive. Sure, we can buy the bottles with pretty labels (I did) but there's a huge amount of hype and bullshit.
I switched to Jacks 3-2-1 (RO) and my formulation is 3.79-2.52-0, thanks to advice and guidance from @FelipeBlu. I also took to heart the advice in the thread "Growing Without Bloom Nutes By Farside05" — that was a real eye opener for me. My next step is to cut down on the number of res changes based on what I'm reading here and here.
Re. water - when you ramp up PPFD (increase your tent temp to the 80's), the plants will respire more so they will transpire more so expect water consumption will be higher than if your PPFD was a "normal" levels.
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- #20
The Pulse One looks very cool. I actually get VPD, Temp and RH from my AC infinity app. I'm happy this kind of information is out there. In theory it should make it easier to see where you're screwing up.
The watering part seems to be slightly lacking on info. Debacco advises the "hand weigh the pot" method too which doesn't strike me as particularly scientific! Some sort of metering or weighing would be good here..
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