LED feed demands

[unnamedmike]

My plants stopped needing cal / mag when I started measuring the intensity of light they receive. Before it had 700w and more than 65,000 lux illuminating an area of 1.8*1.3 meters. Now for the same space I have 500w, and the plants receive 45,000 lux +-. This ended the phantom deficiencies and the need for calmag. The plants are in cococoir, with added CO2.

 

[f-e]

Sounds like nothing Mike, but the math suggests otherwise. 1.8x1.3=2.34meters. 213w per meter. Not a 600. However, if you have 2.7umol lighting, that's 575ppfd if utilised fully. Alright... though the use of co2 is disturbing.
Got any yield comparisons to other lighting you have used?

I have had to take my feeds 50ppm cal to 80ppm cal through transition. I bumped the Mag up 20ppm for a few days, then backed off to 15ppm while I wait for signs. I'm in tiny pots with a full dry back every 24 hours in coco. Just 1L each, which can support 4.5oz plants.

Hi f-e ,
Just braught in a few plants which i veged outdoors under natural light.
I am going to flower them under 1060 w of osram leds at 27 c and 75 % humidity.
My goal here is to monitor the adaptation of these healthy outdoor veged plants to led lighting.
l am not going to change nutrition which is plagron bloom terra (basic dutch fert for dirt).
I will let you know..in a week or two…

I will be watching

 

[searchingforit]

I can't figure LEDs out. I've tried to veg with them and the moment I go above 25% intensity @ 12" above canopy, the plants begin to droop, yellow @ the top, stems turn to wood and purple and interveinal chlorosis sets in. I only water once a day in veg tent so low EC isn't an option. I've gone up to 1.8 EC and I still get the same result. These are smaller mom plants. Watching the apogee man speak on how they blast plants from cutting, I see no reason why I am having issues. If I keep the LED dimmed to sub 10, everything greens up but growth is slow. I should be @ 1000 umol @ 12" with this setup @ 100%. My feed is custom salt mix around 165 N/70 P/200K/70 MG/210 Ca/99S @ 1.8 EC. I've tried every range of EC from 0.8 to max. The speed at which the tops yellow and turn to shit is astounding. If I placed them in all-day sun, they would blow up. Have tried supplemental magnesium sprays and nothing.

 

[searchingforit]

And yeah I understand LEDs run cooler. I have good climate control and stick to 84 F with 65-70 rh in veg.

 

[f-e]

I can't figure LEDs out. I've tried to veg with them and the moment I go above 25% intensity @ 12" above canopy, the plants begin to droop, yellow @ the top, stems turn to wood and purple and interveinal chlorosis sets in. I only water once a day in veg tent so low EC isn't an option. I've gone up to 1.8 EC and I still get the same result. These are smaller mom plants. Watching the apogee man speak on how they blast plants from cutting, I see no reason why I am having issues. If I keep the LED dimmed to sub 10, everything greens up but growth is slow. I should be @ 1000 umol @ 12" with this setup @ 100%. My feed is custom salt mix around 165 N/70 P/200K/70 MG/210 Ca/99S @ 1.8 EC. I've tried every range of EC from 0.8 to max. The speed at which the tops yellow and turn to shit is astounding. If I placed them in all-day sun, they would blow up. Have tried supplemental magnesium sprays and nothing.

Might be Iron.

The main contenders for green issues are iron mag and nitrogen. Some chelated iron is very cheap. Fe-EDTA perhaps.

When you went down to ec0.8 your Ca was still higher than most feeds list. It's higher than your K. Not unheard of, but half is a typical target. K can give white growth and stripes. Like a receding pattern. Not like Iron that starts at the leafs base. High Ca would suppress K and Iron. Actually.. Ca suppresses everything except N. But it's balance with K and Mg are most troublesome.

Having seen Ca as something to boost for most of my time with LED, I'm currently finding the least I can use. My numbers are not far from yours, most about 20% lower but Ca ~90ppm with ~600-650umol

 

[searchingforit]

My micros are 3.45 Fe/0.76B/1.58Mn/0.89Zn/0.1Mo/0.45Cu

I think my iron is appropriate.

 

[searchingforit]

When I turn dimmer up beyond 25% my plants look like the ones "Superbadgrower" posted pages back when he said without very high EC this is what he gets.

https://www.icmag.com/forum/marijua...6485-led-feed-demands?p=12220752#post12220752

That type of yellow occurs and it happens the same day intensity is turned up.

 

[searchingforit]

This forum is amazing, can't even edit posts to add thoughts? I forgot to mention I am in coco. How many times a day are you feeding f-e?

 

[Broggemann]

So, you never fed higher than 1,8 EC?

 

[searchingforit]

Nope. I've never had to feed higher than 1.4 EC outside in full sunlight. I didn't consider it being necessary. I am not above the ppfd and not above 60 DLI these plants would get hit with outdoors, even considering 18 hours of light inside. Maybe I am close to it if I cranked the LEDs up to 100% very close to the canopy? My plants shit the bed @ 50% dim @ 12-18". I will do some experiments with higher EC.

 

[f-e]

This forum is amazing, can't even edit posts to add thoughts? I forgot to mention I am in coco. How many times a day are you feeding f-e?

You can edit at 50 posts.
I size my containers for daily feeding. Usually it will become twice daily in the finals. I tried 3, 5 or 6 a day, but it was just too waterlogged. I like a good dry back. Back to how it came from the sack.

A few years back, I was all for 40% more food. My plants don't like it now though. I'm back at more typical levels, and if I see lighter colouring, I know my runoff has climbed. I can induce this with more light, or drying out a bit much. I'm actually exploring a feed reduction as the light increases. I find some support from the idea more light will make a plant open up for more air. Opening up would regulated by heat they see less of too. So we could have very wide stomata as they want air and are not afraid of too much water loss, based on the temperature they feel. I have used higher EC at higher temps, and as the weather cooled the EC had to come down. I'm focusing on the idea that more light is increasing fluid movement disproportionately as the heat isn't present. This explains a few things I am seeing. Most notably the gathering of food in the pots while the plants get lighter. Which can be washed away, darkening the plants. They do best when the runoff is equal to or lower than the feed.

If this holds true, then it would seem something isn't getting taken at high light. Something left in the pots. I think it might be K. As veg it's worse, and late flower better. It would block Ca and Mg which can show as stripes. Ca gathers in the pot, and it's effect on EC is quite strong.

I must of done 20 under these lights. Everything I learn seems to get undone. I keep detailed logs and what didn't work a couple of years ago, I have found my way back to with fair results. It's not been an easy journey though, with some right mystery issues along the way. The worst grows of my life have been recently.

 

[Greenheart]

Much better info than that other thread! sticky vote!!!

After reading thru it I think Ozz pointed most of it out on post #218.

I have some low temps. Nothing extreme. One plant isn't suffering like the rest did. There are some signs when it gets closer to the light. I think my problem is mostly Mg.

I had good results with a heavy epsom salt top dress and blackstrap foliar feed. They don't look as pretty as Ozz's. Have been struggling since the seedling stage with the chevron and yellowing I'm happy to have come across this thread.

I can't move my lights any higher I might have to point them at the ceiling. lol!

Aside from epsom salt anyone know a good Mg source? preferably organic without the calcium or very low amounts of it. With the oyster shell, crab, dolmite, and other stuff already in there I'm not seeing very much rust.

 

[GoatCheese]

That's interesting. I have gone for more water, and it got worse. Then bigger pots, and it got worse. Drastically so. I'm about to go back to using my smallest and best draining coco dtw yet.

I think you’re misinterpreting the yellowing there to be caused only by LEDs, because over watering also causes yellowing and drooping( leaves pointing down). The symptoms look quite similar and if you haven’t figured out how to dial in the LEDs the right way, it is easy to mix the two different causes of leaf damage as the same issue.

One thing that tells the difference is that when over watering has gone bad enough and the root damage has developed further, leaves start dropping off
...while with LED damage/dehydration yellowing the leaves dry on the plant (won’t drop off).

Years ago i ruined many grows by over watering in soil (too large pots for the plant size) so i know the issue very well, while i’ve also had more than enough troubles with LEDs/COBs. =Very similar looking leaf damge, thou the cause is completely different.

 

[GoatCheese]

Nope. I've never had to feed higher than 1.4 EC outside in full sunlight. I didn't consider it being necessary. I am not above the ppfd and not above 60 DLI these plants would get hit with outdoors, even considering 18 hours of light inside. Maybe I am close to it if I cranked the LEDs up to 100% very close to the canopy? My plants shit the bed @ 50% dim @ 12-18". I will do some experiments with higher EC.

Imo, high EC is only masking the LED issue by growing thicker leaves and more chlorophyll = the damage can still be seen but isn’t as bad cause the plant was fed to be more darker green, but it will ruin the quality of the harvest = harsh smoking weed cause it was over fed while growing.

I would keep the lower EC and raise the lights abit higher if you can, maybe to 25 inches (about 65cm) with 40-50% power

Don’t allow your coco to go too dry while the lights are on, cause this will make the LED yellowing worse, cause it’s a leaf dehydration problem to begin with. Sure, you want to give the pots little time to dry out abit after last watering before the lights go out, but make sure there is still some moisture in coco at lights out.

 

[GoatCheese]

My plants stopped needing cal / mag when I started measuring the intensity of light they receive. Before it had 700w and more than 65,000 lux illuminating an area of 1.8*1.3 meters. Now for the same space I have 500w, and the plants receive 45,000 lux +-. This ended the phantom deficiencies and the need for calmag. The plants are in cococoir, with added CO2.

You tell them, Mike!
All the assumed NPK issues will go away once you get your LEDs/COBs dialed in and keep them hanging high enough over the canopy. The yellowing is a dehydration issue, not NPK deficiency. The only thing i have changed with my feed is i started using CalMag since changing fluoros and a HPS to LEDs and COBs

 

[exploziv]

You can edit at 50 posts.
I size my containers for daily feeding. Usually it will become twice daily in the finals. I tried 3, 5 or 6 a day, but it was just too waterlogged. I like a good dry back. Back to how it came from the sack.

A few years back, I was all for 40% more food. My plants don't like it now though. I'm back at more typical levels, and if I see lighter colouring, I know my runoff has climbed. I can induce this with more light, or drying out a bit much. I'm actually exploring a feed reduction as the light increases. I find some support from the idea more light will make a plant open up for more air. Opening up would regulated by heat they see less of too. So we could have very wide stomata as they want air and are not afraid of too much water loss, based on the temperature they feel. I have used higher EC at higher temps, and as the weather cooled the EC had to come down. I'm focusing on the idea that more light is increasing fluid movement disproportionately as the heat isn't present. This explains a few things I am seeing. Most notably the gathering of food in the pots while the plants get lighter. Which can be washed away, darkening the plants. They do best when the runoff is equal to or lower than the feed.

If this holds true, then it would seem something isn't getting taken at high light. Something left in the pots. I think it might be K. As veg it's worse, and late flower better. It would block Ca and Mg which can show as stripes. Ca gathers in the pot, and it's effect on EC is quite strong.

I must of done 20 under these lights. Everything I learn seems to get undone. I keep detailed logs and what didn't work a couple of years ago, I have found my way back to with fair results. It's not been an easy journey though, with some right mystery issues along the way. The worst grows of my life have been recently.

To be honest your K excess theory that fucks up the cal mag uptake is about the same as I am trying to figure out in my grows. Only diference is you seem to know what you talking about, while I am on my last straw trying to figure this and avoid it.
what would I need to add or remove from my soil/feed so I test if this is really the problem.
any ideea?
thank you!

 

[GoatCheese]

To be honest your K excess theory that fucks up the cal mag uptake is about the same as I am trying to figure out in my grows. Only diference is you seem to know what you talking about, while I am on my last straw trying to figure this and avoid it.
what would I need to add or remove from my soil/feed so I test if this is really the problem.
any ideea?
thank you!

f-e’s excess K theory comes from coco leaching out Potasium over time and them messing up his thing, while you grow in soil. So this should not be a problem for soil growers.

 

[f-e]

215w per meter mike. Similar to GC. I see improvements up to 450w. Which is an indicated 25-30000lux on my two meters. One of which is calibrated against a real meter, saying I have about 700ppfd. The youtube professors have used 1500 from a very young age, but I have no idea if that's supplemental LED use, or how they are fed. You may have 400ppfd which sits inside the optimum window of 400-750 and 400 shouldn't stress anything. While 1500 is so demanding, I can see why they have their jobs.

I might have some maths issues, but when I try to disprove myself, I just get agreement. I'm unhappy with how much we loose between luminaire and canopy. About 30% seems typical. 215w of 2.7umol.J lighting should offer up 575 but after the board coatings, reflections and the amount that lights up the wall, 400 on the plants is good. I'm showing my 'working out' though, as I'm not 100% happy with it.

If there were a drying out, that would point to moisture loss from wide open stomata or a weak root and stem system. I have entertained the stomata idea a lot recently. Specifically our control of it with K. Leading to a move from coco with it's high K, to soil. Where the issues I attributed to the K, have gone. I guess leaves drying out could be linked to excessive uptake of something not being used, if it were in a high enough quantity to be physically in the way. P&K seem the best bets in that instance. I struggle as the plants move from P too K demand, and I see Mg becomes less available.
Everything comes back to K in so many chains of thought, I had to come out of coco.
As a side note, I just did two beans. One coco one soil. A side by side of limited use, but my first such under LED. The soil plant is well ahead. Not just a bit, or what you expect between beans. It's storming ahead in canna's terra beside their coco.

As I 'have it in for K' it's worth considering it's battle with Ca. If a plant were to pull more K in order to get the stomata flexing, then Ca would suffer. While increasing the Ca would reduce the K taken. It's all a bit much for our level of plant understanding though. Much of our 'cause and effect' learnt understanding, won't stand under LEDs.

Why are LEDs that different? It's the heat. That lack of IR. We can warm our rooms, but that's not the same as a good IR heat source. We know that 730nm works along with the 660 but find more 660 adequate in general horticulture.
Perhaps we need a thread to simply see who is using what lights, and there stories of struggles or success. To see if the lights with IR emitters are doing better.
It's difficult to see through the mist sometimes. If we offer up LEDs as a problem, people will blame their problem on LEDs. It's so easy to blame the tools, not the worker.

My plants are getting less and less interested in stretching, over the time they have lived under LED. I bet some 730nm would leave them floundering


I don't really get a drying effect, but associate a chalky appearance, oddly enough, with a lack of chalk. An important part of building green. A pH shift usually fixes it.

 

[f-e]

f-e’s excess K theory comes from coco leaching out Potasium over time and them messing up his thing, while you grow in soil. So this should not be a problem for soil growers.

Yes it's coco I'm looking at as a K source. The age of the coco should be an influence, but it does it all the time. No K for a few days, and still 90ppm in my runoff, with 3 or 4 fertigations a day. That's a lot of K coming out. There were plants in them pots eating some of what the coco released. I couldn't see it all in the runoff report.

I have run coco for some time. There was no problem with HIDs and also large pots do a good job of alleviating the signs I see. I'm amplifying the problem with small pots. I have always had something going on in small pots. What this amounts to, is that while I'm looking at the K in coco, I didn't under HID. So it's not just the coco, but a combination of coco and LED.

I wouldn't discount the idea that LED and soil could see similar issues, when we look at how many soil types their are. As in my post above, I'm wondering if he plant opening the stomata further is leading to greater K uptake. K being a great regulator of stomatal opening in our 'cause and effect' studies of plant growth. Back to the IR, and it's probable contribution towards stomata opening. Like a line of procession. Low IR leaves stomata opening wide. Needing K. Making Ca and Mg problems. So green can't be made fast enough for the elevated light, and we can't forget, elevated co2 from them openings.

Do you have a problem thread Calibri? I would like to take a look at what you are seeing.
K Ca and Mg are a little group that needs balance. Traditionally 4:2:1 but many are formulating their own feeds and taking Ca above K which would suppress it. In soil though, you have so much Ca already, that another approach might be needed. I could do with having a look. I'm really no expert though. I'm struggling along myself. As yet, with no conclusive proof of anything.

 

[exploziv]

So I have P, Ca, Mg deffs. Distance from leds or leds intensity doesnt change much of it. Feeding double full doses of nutes almost every watering seems to fix it for a while, unless 3 times max dose is what they need. But then N is through the roof, as i use organics and almost all of them have some N.
I am bummed. What can I do to improve my situation? I plan on starting fresh with simpler soil mix snd simpler feed regimen trying to figure it out as I go. What would you guys do?