Hollatchaboy
Well-Known Member
So in your experience, what's the tell tale, that you hit the light saturation point.
Side lighting
- Thread starter cronik john
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cronik john
Well-Known Member
I'm gonna ramp up another 10% tonight and see how they take it. So far they're loving the extra light. I feel like since the side lights got put lower I can probably get top light to full power by this weekend if they accept well enough. And ramp up side lights 10% this weekend. In the mean time heres a little root porn from last night
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Southside112
Well-Known Member
Nice write up. Only thing I would add is Led's can cause light damage if too close to the plant or too high ppfd. Good led's are super efficient and powerful. I agree though get to the light saturation point and keep them healthy and you should have good results. For me as mentioned that sweet spot in flower is around 1000 ppfd at canopy.
Southside112
Well-Known Member
Like previous poster said research suggest that 1000 ppfd is the sweet spot without co2. Get there and you should be gtg.
Hollatchaboy
Well-Known Member
All this is strain relative though. Just like nutes. Some like high ec, some don't. With the nutes, it can be obvious, with the light, not so much. That's why I was asking, what's the tell take sign you've hit the saturation point, and haven't gone beyond?
cronik john
Well-Known Member
Then I was definitely not doing enough last round because I was only about 850 ppfd maxed out with the lights pretty high up. That's what brought me to this point. I'm gonna play with my light tonight
Southside112
Well-Known Member
Fair points. Idk specifically the answer to your question. Agree 100% on nutes. I run fems and not unusual to have 4+ strains going at once. They all definitely have different nutrient needs.
Southside112
Well-Known Member
I've had really good results around 850ppfd for what's it's worth. Getting to 1000ppfd might add 20% to yeild and help density as well. Cheers.
Hollatchaboy
Well-Known Member
And potency. I'll agree with the 1000ppfd, but the charts say to hit that level for one week, at week 7 from flip.
I've heard bugbee say to hit them with the 1000 also, but your environment and nute schedule, have to be on point.
It's hard to hit those nute levels growing organically. With salts, no problem. You can tailor nutrient requirements, to match the light levels.
cronik john
Well-Known Member
I'm running athena pro nutrients at 1500 ppm all the way through flower in coco. My tent vpd is spot on in the room I'm in I have it controlled too.
Leaves tacoing/canoeing and/or rotating around the petiole (like a Venetian blind). I've also ended up with a cola that was slightly bent at the top. And you may end up with foxtails.
The tacoing/canoeing is a result of auxins moving from the illuminated side of the leaf to the shaded side. The the additional auxins, the shaded side of the leaf expands and/or grows (that's a supposition on my part) and the top part of the leaf curls around, reducing exposure.
In the case where the cola bent, it was a large cola (I grow in hydro so plants tend to be larger) and there was an obvious bend about 2" down the cola.
In one grow, where I was trying to light a 3' tall plant and a 1' tall plant with the same light, I ended up with foxtails on the larger plant. That was a dumbshit move on my part. I did buy an XS 1500 for the little plant but the larger plant didn't revert.
These are the lights values for my most recent grow.
I went back through that journal, searched for "drop" and read through the first couple of months of commentary. Here's what I found:
Day 23, PPFD of 798, DLI 60
"Dropped PPFD. Center plant at 708 was starting to taco. Set Dehu to 40. VPD slowly climbing. But temp dropped almost…"
I reduced input wattage, probably by 10% since it was 10%± PPFD reduction. New PPFD 634 DLI 55.
Day 24
I lowered the light a bit, PPFD 671 DLI 58
Later that day "Nice to see PPFD. I'll bump it tomorrow AM.. Next stop 750?"
"Increased wattage to 198 but looked at the plants and some of the leaves on Left look like the they're shallow V-shaped.
Dropped wattage back to 180. PPFD is a little higher today but they did grow overnight so that could be that I'm measuring differently. Only one value is different so I'm guessing is a measurement error. "
That's the only mention of a light issue but, in the spirit of full disclosure, it's routine for me to have to drop PPFD a little during the course of a grow. I see no downside to this. The plant reacts to…an error condition and I resolve it.
One behavior that's common is for leaves to "pray". My belief is that this occurs when the plants are on the cusp of their LSP but found no research on that and I've never tried to manipulate light levels to see if that's the case.
I've read that posts that growers conclude that plants "have had enough light" if they droop just before lights out. I do not believe that to be correct. The light saturation point is a function of PPFD, not of DLI. Second, I suspect that drooping leaves are a function of turgor. Finally, we know that plants respond to a circadian rhythm and I suspect drooping leaves one of the behaviors.
Thank you. I appreciate the feedback.
Re. 1k — what are your yields like in comparison to estimated yield from the vendor (if you're using seeds)?
cronik john
Well-Known Member
Mind blown... I've never been good at keeping record of my grows but now I have a reasonLeaves tacoing/canoeing and/or rotating around the petiole (like a Venetian blind). I've also ended up with a cola that was slightly bent at the top. And you may end up with foxtails.
The tacoing/canoeing is a result of auxins moving from the illuminated side of the leaf to the shaded side. The the additional auxins, the shaded side of the leaf expands and/or grows (that's a supposition on my part) and the top part of the leaf curls around, reducing exposure.
In the case where the cola bent, it was a large cola (I grow in hydro so plants tend to be larger) and there was an obvious bend about 2" down the cola.
In one grow, where I was trying to light a 3' tall plant and a 1' tall plant with the same light, I ended up with foxtails on the larger plant. That was a dumbshit move on my part. I did buy an XS 1500 for the little plant but the larger plant didn't revert.
These are the lights values for my most recent grow.
View attachment 5460751
I went back through that journal, searched for "drop" and read through the first couple of months of commentary. Here's what I found:
Day 23, PPFD of 798, DLI 60
"Dropped PPFD. Center plant at 708 was starting to taco. Set Dehu to 40. VPD slowly climbing. But temp dropped almost…"
I reduced input wattage, probably by 10% since it was 10%± PPFD reduction. New PPFD 634 DLI 55.
Day 24
I lowered the light a bit, PPFD 671 DLI 58
Later that day "Nice to see PPFD. I'll bump it tomorrow AM.. Next stop 750?"
"Increased wattage to 198 but looked at the plants and some of the leaves on Left look like the they're shallow V-shaped.
Dropped wattage back to 180. PPFD is a little higher today but they did grow overnight so that could be that I'm measuring differently. Only one value is different so I'm guessing is a measurement error. "
That's the only mention of a light issue but, in the spirit of full disclosure, it's routine for me to have to drop PPFD a little during the course of a grow. I see no downside to this. The plant reacts to…an error condition and I resolve it.
One behavior that's common is for leaves to "pray". My belief is that this occurs when the plants are on the cusp of their LSP but found no research on that and I've never tried to manipulate light levels to see if that's the case.
I've read that posts that growers conclude that plants "have had enough light" if they droop just before lights out. I do not believe that to be correct. The light saturation point is a function of PPFD, not of DLI. Second, I suspect that drooping leaves are a function of turgor. Finally, we know that plants respond to a circadian rhythm and I suspect drooping leaves one of the behaviors.
I've never found a "chart" that's based on research. Lots of conventional wisdom, lots anecdotes, and lot of people with making proclamations based on their "years of experience" (common elsewhere but not that common here on RIU) but no data, no research, and, as I learned many decades ago, experience ≠ expertise.
The worst of the lot is the drek that the folks at Photone publish.
The light saturation point for cannabis is, per conventional wisdom that I pooh poohed in the para above, 800-1000µmol. My take is that if you can't get your grow to that light level, that's a sign that something's going sideways with your grow environment.
There's only about a dozen things in "the grow environment" and a lot of them are trivial to get "in range". To me, soil and watering are where things hit the skids. That's why I went with hydro—it's a completely clean slate//there's nothing hidden. Soil's part voodoo to me.
I didn't realize that about organics.
Re. tailor nutrient requirements — I don't change nutrients in response to light levels. My ferts have the same ratios the course of a grow (Jacks's 3-2-1) but I do change the EC as the plan matures and moves through the stages of its lifecycle. As a plant grows larger, it naturally takes up more nutrients due to increased transpiration.
Journaling can be very helpful. Excel does the trick for me.
Hollatchaboy
Well-Known Member
Agreed with pretty much everything. When I say tailor, I mean with salts, you can basically give the plants the correct ratios of nutrients. With soil it's more of a crap shoot. You have to do your best to give the correct organic matter, at the right amounts, at the right time, and do your best to keep microbial life at highest levels.
Soil is definitely voodoo. You're basically relying on microbes to produce the nutrients.
Hollatchaboy
Well-Known Member
Im right there with ya, other than a couple bean plants in grade school, but my mom was actually growing them for me.Thanks for that info.
Besides cannabis, the only thing I've ever grown is old.
Southside112
Well-Known Member
For me it follows container size roughly if I do my part. I'm in ffof soil with bottle nutes. So for 2 gal pots 2 ounces is about right. 3 gal pots 3 ounces and so on and so forth. Now hydroponics changes everything. I've gotten over a pound in a 3x3 with a recirculating dwc that I made. Coco around 30% more than soil roughly. As always ymmv. I run either cobs or Samsung boards for lighting BTW.
That's the "growing" part but "old" at 52? Hah!
And…
I'm "Generation Jones" so not quite a Boomer.
