LED feed demands

[SuperBadGrower]

Yeah a couple degrees means a night and day difference when I walk into my room... my dehumidifier can barely keep up at good temps, but when it is 24C I "almost don't need it". (exaggeration of course)

In some recent research, benefits from infrared addition are being found

I have posted this presentation with timestamps which will interest the readers here: https://www.icmag.com/ic/showthread.php?t=361167

 

[hayday]

I noticed the same. I assumed the temperature drop was responsible.I feed every other day now when with HPS,I fed every day.
I also watch my runoff,if it exceeds 1500ppm I do water after a skip day and then back to feed.

 

[Douglas.Curtis]

Sure, I think you can make some generalizations about the phosphor coated leds (white leds). they all have a pretty similar spectrum.

There's actually a significant difference, depending on the configuration and choices of LEDs being used. 70CRI and 90CRI are different, the lenses used and Kelvin ratings they produce are very different (yes, I'm aware of LED construction).

Plants convert light, and the type of light drives their needs. So, while I wouldn't say you can make a generalization for all LEDs, I would imagine the 'preferred' LED spectrum for cannabis quality/yield compromise is close to a slightly redder MH. The spectrum Fluence posts would be a general example.

Very interesting responses in here.

 

[hush]

After all those of years of growing under HIDs, I, too, felt like a noob again after switching to LED. There's a learning curve there for those of us who pre-date LED grow lights. It's about unlearning. And the main thing to unlearn, which has already been touched on, is keeping the light right on top of the canopy. I mean, this is only my experience, so I'm not claiming this is necessarily science or anything, but it took me several years, several different growing methods and a bunch of trial and error to start feeling advanced again, lol. After all this time, now, I feel like I figured out the main trick: keep LEDs much further away from the canopy than you did with HIDs!

Once I figured that out, everything fell into place, and I no longer felt like my plants were growing slower than they did under HPS, no longer felt like I had to use a different concentration or ratio of nutrient, etc.

 

[Zomboy]

On my second LED grow and im also running into issues, the learning curve is real. Some good info in here

 

[Douglas.Curtis]

Ty hush, very good points.

 

[exploziv]

After all those of years of growing under HIDs, I, too, felt like a noob again after switching to LED. There's a learning curve there for those of us who pre-date LED grow lights. It's about unlearning. And the main thing to unlearn, which has already been touched on, is keeping the light right on top of the canopy. I mean, this is only my experience, so I'm not claiming this is necessarily science or anything, but it took me several years, several different growing methods and a bunch of trial and error to start feeling advanced again, lol. After all this time, now, I feel like I figured out the main trick: keep LEDs much further away from the canopy than you did with HIDs!

Once I figured that out, everything fell into place, and I no longer felt like my plants were growing slower than they did under HPS, no longer felt like I had to use a different concentration or ratio of nutrient, etc.

While I don't disagree with you, it all depends on the led diodes themselves, the lens agle and power. Less power diodes need to be kept closer than hids, while big units powered by cobs or having narrow angle lenses need to be kept at a greater distance.
Also, I'd say keeping leds too close won't result in more defficiencies, plants will just progress slower or get bleached tops (if leds are really powerful and kept really close, so what others said remain valid as well.
But I totally agree that once you hit the sweetspot you can be happy with the results.

 

[f-e]

I'm starting to think I may need a P boost. Making that three people boosting N & P. Could I see that as a reduction in K instead? Which is what's happening to the feed profile, by raising the N & P. If so, then why. What is K, and why need less. K is used in stem growth. Our led's don't really promote stem growth, due to the lower shade response from having little far red. This could be starting to explain how led's demand a different feed profile. Less K due to less stem growth. More Ca and Mg is hard to explain, because they are often lacking anyway. But if it was Ca deficiency driving this, it's likely temperature based. As somebody posted on the last page.

It's weak I know, but it could be something.

edit: I forgot.. K is also involved with transpiration. The first sign of deficiency being burnt serrations. Which led's are less likely to promote

 

[Shmavis]

Thanks for this thread. And to all who’ve contributed. I will be following along with great interest.

I too am now a newb because I switched to LED. After many years of growing under HID I settled into a method of pampering my plants when seedlings and while vegging. And then more or less put them on autopilot during flower - mostly only checking for watering needs. This last year I did back-to-back grows under an HLG 550 V2 and neither was what I would consider successful with the second of the two more of a disaster than the first. Each set of plants vegged beautifully under the light, but around week 3-4 of flower, things started going downhill fast. I found my old method no longer applies and as I get ready to fire the panel back up in a month or so, I am going to need to make adjustments. I also have a COB panel with a 420w actual draw. I did much better with this light and found, as was recommended to me, one key seemed to be running high temps (84 - 87) and high humidity. I wasn't as vigilant reaching those numbers under the HLG, but plan on it this time.

I am not so sure I agree that LED allows for deficiencies that weren’t seen under HID to show themselves. I say this because I regularly used to remove plants from the flower room to look over, pollinate, rotate, etc. I didn’t have problems like now, even when viewing under normal household lighting.

I need to somehow figure out how much cal and mag I need to amend my soil mix with. Guess I’ll use gypsum for cal, not sure what for mag yet. Think a soil test is in order. Hopefully turnaround time on them is fast.

 

[RB56]

Thanks for this thread. And to all who’ve contributed. I will be following along with great interest.

I too am now a newb because I switched to LED. After many years of growing under HID I settled into a method of pampering my plants when seedlings and while vegging. And then more or less put them on autopilot during flower - mostly only checking for watering needs. This last year I did back-to-back grows under an HLG 550 V2 and neither was what I would consider successful with the second of the two more of a disaster than the first. Each set of plants vegged beautifully under the light, but around week 3-4 of flower, things started going downhill fast. I found my old method no longer applies and as I get ready to fire the panel back up in a month or so, I am going to need to make adjustments. I also have a COB panel with a 420w actual draw. I did much better with this light and found, as was recommended to me, one key seemed to be running high temps (84 - 87) and high humidity. I wasn't as vigilant reaching those numbers under the HLG, but plan on it this time.

I am not so sure I agree that LED allows for deficiencies that weren’t seen under HID to show themselves. I say this because I regularly used to remove plants from the flower room to look over, pollinate, rotate, etc. I didn’t have problems like now, even when viewing under normal household lighting.

I need to somehow figure out how much cal and mag I need to amend my soil mix with. Guess I’ll use gypsum for cal, not sure what for mag yet. Think a soil test is in order. Hopefully turnaround time on them is fast.

Dolomite lime has both calcium and Magnesium.

 

[Douglas.Curtis]

Each set of plants vegged beautifully under the light, but around week 3-4 of flower, things started going downhill fast.

Let me guess... plants looked like a mag deficiency with yellowing leaves, but didn't respond to addictional mag? If so, put some 1" thick potato slices on top of your media. Check it in 4-5 days and you'll most likely see root aphids.

 

[wvkindbud38]

I had some plants indoors under Leds, and took them outdoors and it was crazy how the leaves kinda had a blue kinda look. You could just tell a mile away, those plants kinda kept that odd color for along time in Veg even after beening outdoors for wks

 

[GOT_BUD?]

Same here... I was thinking more Feather meal for N and Rock Phosphate for P and keep feeding kelp extract and fish Hyd like a mofo..

Got a product for free where I bought the Led , its called Led Protekt and has bio available minerals with Salcydic Acid..thers lots of magnesium and manganese , potassium and some silicates....plants love it...same response of when I give em aspirin!!

I'm really starting to think that a water only soil recipe is going to be very difficult to achieve under LED. Especially if you have plants with a big appetite like I appear to.

I don't know. Maybe after 5 or 6 grows and constantly amending heavily and tailoring the cover crop you can achieve a water only recipe for heavy feeders. But from the get go requires a level of knowledge I have yet to acquire it appears.

Adding fish hydrolysate with kelp to my ACT may become a permanent addition anyways because of the huge increase in microbial activity I observed under my microscope. Tad Hussey and Microbeman are right - foam means nothing with ACTs.

 

[f-e]

Water only? (nothing else in this post)

I have a 1.2 tent area, with 120w running. It's wall to wall solid with plants, and even at that light level I have been running an EC of 1.7 to keep them happy. That's under 10w per foot of citizen cob. Yet still I can't run a sodium like EC of 1.3

Few compost reviews have passed before me, but the 'which' magazine (a subscription only magazine, priced like a hardback book) reviews sometimes get copied to the net. Hundreds of gardeners, using a range of plants get involved. The results for high energy plants are given for standard and organic. I believe this means I have tried good compost. I don't think it can be done, without a seriously large amount of peat. In the UK, this means Jacks Magic, and there is literally no other option imo.

I think canna terra is the real soil option, but really it's hydro. A weak compost, with a full range food you use all the time.

Great respect to anyone that can use led's and a homemade compost, even with feeding. That is some master growing right there.

I will get that 10w pic some time soon, so you can see it's not some sparse joke. I think the lack of IR heat, means they don't need to sweat, so instantly you need food levels that may be 40% greater. That's a hot compost, unless you can have some well timed release. So it won't be on the shelf.

 

[Ichabod Crane]

I am running Jack's 5-12-26 with calcium nitrate.

I mix my Jack's stock solution at 880 grams per gallon of RO water.

I mix my Calcium Nitrate at 660 grams per gallon of RO water.

These are my stock solutions. I use 70 ml of each per 5 gallons of RO water. To this 5 gallons I also add 1.5 tsp Epson salt. I PH this to 5.8-6.0.

I use this in coco coir.

I noticed that I got deficiencies with in 3 days if I did not feed this to fresh clones before pitting them under LEDs that were 30+ inches up. These were clones just put into cups rooted in rapid rooters. This never happened under HPS.

I also had the same thing happen when I moved larger plants from HPS to LED. This is why I use 70 ml verses when I was under HPS and only using 50 ml. That was a jump of 40% in feed plus adding Epson salt.

I also noticed that I need to add 2 table spoons of MKP per 5 gallons when in flower or I get purple stems and black spots on the leaves. Purple stems is cause from a lack of potassium. The black spots are from a lack of phosphorus.

I also have to keep the LED lights at or above where I kept my HPS. If I dont I get foxtailing and fluffy buds.

Here is what I am getting under LED.

 

[DARKSIDER]

I am running Jack's 5-12-26 with calcium nitrate.

I mix my Jack's stock solution at 880 grams per gallon of RO water.

I mix my Calcium Nitrate at 660 grams per gallon of RO water.

These are my stock solutions. I use 70 ml of each per 5 gallons of RO water. To this 5 gallons I also add 1.5 tsp Epson salt. I PH this to 5.8-6.0.

I use this in coco coir.

I noticed that I got deficiencies with in 3 days if I did not feed this to fresh clones before pitting them under LEDs that were 30+ inches up. These were clones just put into cups rooted in rapid rooters. This never happened under HPS.

I also had the same thing happen when I moved larger plants from HPS to LED. This is why I use 70 ml verses when I was under HPS and only using 50 ml. That was a jump of 40% in feed plus adding Epson salt.

I also noticed that I need to add 2 table spoons of MKP per 5 gallons when in flower or I get purple stems and black spots on the leaves. Purple stems is cause from a lack of potassium. The black spots are from a lack of phosphorus.

I also have to keep the LED lights at or above where I kept my HPS. If I dont I get foxtailing and fluffy buds.

Here is what I am getting under LED.

[URL=https://www.icmag.com/ic/picture.php?albumid=78759&pictureid=1918927]View Image[/url]

[URL=https://www.icmag.com/ic/picture.php?albumid=33219&pictureid=1932393]View Image[/url]

[URL=https://www.icmag.com/ic/picture.php?albumid=33219&pictureid=1917860]View Image[/url]

Nice buds indeed and a very good thread too.

 

[Lost in a SOG]

Its a bit of a misnomer to say plants under leds eat more but they definitely seems like they can eat more so long as your humidity, temps, co2 and pH are on point.

I dont rate quite a few led options out there especially if people arent using PAR meters to keep an eye on their DLI. The need for food could be as much down to the quality of the photons the led light is putting out as well as maintaining a good DLI.

Also imo a lot of led rigs dont have a great throw or penetration through the canopy and only keeping a decent sog canopy will mean the plants are able to maintain high photosynthesis accross the board.

For trees i think cobs are best as they seem to have better penetration than many lower wattage individual diode setups.

I have read many say the have to up their ec because so much more wattage in leds is in the PAR band as a pose to IR like HPS put out. I still think its a lot to do with DLI.

 

[Ichabod Crane]

I built my LEDs because most lights dont have good spread. And the ones that did cost way to much and are not flexible. The lights I have are 4 inch wide by 40 inches long. Each is about 192 watts. So it is quite easy to bank them together to get better penetration of the canopy.

 

[h.h.]

I’m not water only.
I topdressed early on, then threw a handful of Espoma in the bins early in flower.

I agree spread is best.
I run hybrid. Cobs on top, QB’s on the sides.
Still had the yellow until I added red. I think I added UV at the same time. Again not sure that’s what eliminated it.
I ran red last grow and didn’t see it at all.

I have cuttings in a 5x5 with 200w 3500k cobs and they show it.
It seems like incomplete photosynthesis to me. I’ve never heard of it.
The center leaf is dark. Like the nutrients stop traveling once they enter the leaf. Otherwise, the plants look healthy. Grow normal. They don’t seem to be underfed.

[/IMG]

 

[h.h.]

I built my LEDs because most lights dont have good spread. And the ones that did cost way to much and are not flexible. The lights I have are 4 inch wide by 40 inches long. Each is about 192 watts. So it is quite easy to bank them together to get better penetration of the canopy.

[URL=https://www.icmag.com/ic/picture.php?albumid=33219&pictureid=1977426]View Image[/url] [URL=https://www.icmag.com/ic/picture.php?albumid=33219&pictureid=1972719]View Image[/url] [URL=https://www.icmag.com/ic/picture.php?albumid=33219&pictureid=1922577]View Image[/url]

https://www.alibaba.com/product-det...m=a2700.wholesale.maylikehoz.4.1120445dvvJkGs