LED feed demands

[SuperBadGrower]

~900 ppfd
~86F
nothing but white diodes

https://manicbotanix.com/light-co2-temperature-relative-humidity-and-photosynthesis/

 

[THC123]

Interesting read, explains wat They react differently to a different spectrum at the same par values! This question was driving me crazy. Wow superbad grower, you really are one of the worst growers! Those plants look so bad!!! Jk whatspectrum are They under?

 

[SuperBadGrower]

Haha =) 3000K these, 80 CRI (All I have is 80)
Some are vegged under 3000K, others 3500K, no difference between those 2 to me.
Using about 35-45w / sqft

Yeah man everything on that website is absolutely on point! anyone struggling with grasping information about growing should absolutely make it a priority to read everything they offer there. I'd put some other good links that are relevan, but I'm pressed for time.

Just to give some extra faith that everybody can make it with white diodes (well, until week 4 at least )! Mine are on hydroponic feed but if you are on point with your transplants, living soil or whatever you may use, it should be good! Keep at it Cheers

edit: again here the link to the website:
https://manicbotanix.com/light-co2-temperature-relative-humidity-and-photosynthesis/

Go to Grow info menu for more
I'm not affiliated in any way. I think they make nutrients (I never used / never plan to use them).

 

[Shmavis]

yeah that is my issue as well. It looks like there is too much light but the meter says it is ok. Only have this with qb,s. Under my blurple (or any other lightsource)i can start seedlings at 300 500 pond without issues....
Or there is something wrong with your lights or we are doing something horribly wrong.

Yeah, it's a head-scratcher for me. Just measured a 125w CFL at about 4" away and read ~400. Seedlings thrive under it. Found the same HLG 65 did likewise to some seedlings sown in Light Warrior. That's why this time I went directly into my soil mix, knowing there's ample nutrients. Plus, if general understanding is that a seed has all the nutrition it needs for close to the first two weeks, how to explain all this other than to say it's the light? I potted up the seedlings two days ago. Pushing forward to see how they do. Most were for germ test so willing to sacrifice them, but do care about the four in the center so if they do not bounce back will move them under CFL.

Haha =) 3000K these, 80 CRI (All I have is 80)
Some are vegged under 3000K, others 3500K, no difference between those 2 to me.
Using about 35-45w / sqft

Yeah man everything on that website is absolutely on point! anyone struggling with grasping information about growing should absolutely make it a priority to read everything they offer there. I'd put some other good links that are relevan, but I'm pressed for time.

Just to give some extra faith that everybody can make it with white diodes (well, until week 4 at least )! Mine are on hydroponic feed but if you are on point with your transplants, living soil or whatever you may use, it should be good! Keep at it Cheers

edit: again here the link to the website:
https://manicbotanix.com/light-co2-temperature-relative-humidity-and-photosynthesis/

Go to Grow info menu for more
I'm not affiliated in any way. I think they make nutrients (I never used / never plan to use them).

Seems to be the point in time where things go awry for me under LED. Thanks for the link and info - will check it out later. And I agree, your babies are looking real good - for a super bad grower.

 

[Mr. J]

This is my third grow under LED and the plants are loving it. I'm feeding them exactly as I would under HPS and the only thing I had to do differently is the temperature, which is a few degrees warmer. I don't have a light meter but it's damn bright in there, can't even look inside without glasses.

 

[SuperBadGrower]

^ great stuff!

Seems to be the point in time where things go awry for me under LED. Thanks for the link and info - will check it out later. And I agree, your babies are looking real good - for a super bad grower.

What happens? I have a similar experience with peat mixes. With that stuff I found it hard/impossible to correct because of the CEC and the nutrition present in the mix. That's one reason why I switched to coco. Having/maintaining the right amount & balance of nutrients in a soil mix is really an art. It's easier said than done I guess..

I'm not really a beleiver that a seed can go 2 weeks with what's in the cotyledons, that's not true at all IME. I fucked up plenty of times with coco. For example if you get fresh high quality coco and don't treat it properly, it will be a very low EC and barely any nutrients will be available. You put a seed in that, you will see the cotyledons yellow extremely fast. in days. (And then the plant starts to stunt ofc)

My experience is that the typical bag peat mix (that's ~1.2 EC of nutrients) starts great seeds. On a side note, when I researched peat mixes it turned out that, when tested, quite a few were a bit hotter than advertised.

& for the rest I would say again to not trust meters at all unless it is an apogee or li-cor. Use them to measure the spread of one type of light source, yes, but don't use them to compare light sources. You guys would not believe how absolutely fucking stupid I felt as I compared my lux meter readings with apogee sensor. (Sorry if I'm preachin to the choir, I don't know or remember which sensor you have)
The same kind of feeling crept over me when I tested my first "TDS meter", and it turned out that I had been overfeeding by more than 30%...hehe

 

[saitama]

Joining in.

 

[Shmavis]

^ great stuff!



What happens? I have a similar experience with peat mixes. With that stuff I found it hard/impossible to correct because of the CEC and the nutrition present in the mix. That's one reason why I switched to coco. Having/maintaining the right amount & balance of nutrients in a soil mix is really an art. It's easier said than done I guess..

I'm not really a beleiver that a seed can go 2 weeks with what's in the cotyledons, that's not true at all IME. I fucked up plenty of times with coco. For example if you get fresh high quality coco and don't treat it properly, it will be a very low EC and barely any nutrients will be available. You put a seed in that, you will see the cotyledons yellow extremely fast. in days. (And then the plant starts to stunt ofc)

My experience is that the typical bag peat mix (that's ~1.2 EC of nutrients) starts great seeds. On a side note, when I researched peat mixes it turned out that, when tested, quite a few were a bit hotter than advertised.

& for the rest I would say again to not trust meters at all unless it is an apogee or li-cor. Use them to measure the spread of one type of light source, yes, but don't use them to compare light sources. You guys would not believe how absolutely fucking stupid I felt as I compared my lux meter readings with apogee sensor. (Sorry if I'm preachin to the choir, I don't know or remember which sensor you have)
The same kind of feeling crept over me when I tested my first "TDS meter", and it turned out that I had been overfeeding by more than 30%...hehe

Still not sure exactly what is happening other than to think, as others mentioned, metabolism rates are supercharged and I do not have enough N, along with other nutrients in my soil mix to satisfy. I did include neem seed meal one round to up N but still found yellowing and generally unhappy girls. I will be doing a comparison run with some clones this fall as I will be firing up the HPS again. While I have never grown in coco before, I have to imagine these hurdles are easier to overcome in that medium.

It's not pH related either. I have a Blue Lab soil pen and have monitored soil as well as pH of water... I have definitely found that some plants just can't handle PPFD levels that are often said to be target ranges.

If we say you're correct and two weeks isn't stored in the seed, then is what I experienced just light intensity? The first time I used this light I had seedlings not too long above ground when I swapped out the CFL with this light. Within a day the babies took a dramatic turn for the worse. They were in Light Warrior. These babies were sown directly into my soil mix - no reason they shouldn't have any available nutrient needed. And I eliminated the possibility of the light change and intensity (was only 12" away first time) as the cause by starting these under the light at a more than safe distance and less than 150 PPFD.

They are doing better. I transplanted into SOLO cups. Changed nothing else. New growth is looking healthy for the most part.

I have the Apogee SQ-120. Definitely not top of the line and requires being wired to a multi-meter, but believe it is the same sensor used on a couple of the higher end models. I rigged up a wand from PVC to get reach for multiple location readings.

You can see I started with a a LUX meter too, and like you I found those calculations to be way off from what the Apogee was reading.

 

[SuperBadGrower]

Oh thats a good sensor man, yeah ignore what I wrote hehe.

Heres my 2 cents looking at that picture:

I agree, the new growth & plant shape is looking great! if that keeps up it will be fine. Its looking vigorous as it should.
Just stay on point with the transplants is the easiest approach I think. it looks like the plants are taking off. once they get rootbound you get problems so fast in intense environments.

Issues in interveinal areas, leaf tips, and also at the serrations point to a (history of) multitude of deficiencies. Making it difficult to diagnose in terms of elements

Which means it should also be simple to fix, more/enough of everything! And ample root space for new root tips to keep growing.

Ofc it's hard for me to try to say whats the problem with a soil mix, it could be so many things


Finally I would say, my experience starting seeds is that I actually have to put quite intense light on them if I dont want the hypocotyl to stretch. (That really annoys me)
With blue+red, plants would develop the first set of leaves right where they emerged from the ground. But with white LEDs it seems like I need to put higher ppf on them to prevent hypocotyl stretch. I cant say I've measured it but it must be 300-450.
I start seeds in the same EC as veg and stuff, which by most people standards would be high. I would never use seed startinng mix, or something with a really low EC. That's for plants which are pussies IMO. Cannabis is pretty beasty it can eat a lot. When I used peat I started the seeds in the 1.2-1.4 EC mixes.

 

[kritios]

Great thread, subbed.






This is my first run with an LED, no problems evident so far. I just put her in flower.



I run a hot soil with promix bx, perlite and EWC at 6:2:2 then add guanos and hi-cal lime. This mix has served me well before, but after reading this thread I top-dressed some cal-mag on the plant around week 3 of veg.

 

[OZZ_]

I’m having the same issues as everyone else. Organic soil grower that has zero issues under hps, now switched to LEDs and I have issues in veg, mostly I’m able to iron things out by flower with going extremely low on the dimmer. After reading through this thread, I’m convinced it’s temperature related. The LEDs run so cool my tent is at 76F, and come to think of it by the time I switch to flower they are able to handle more light which increases the temps in there.

I guess it makes sense if you think about it in simple terms. What I’m hearing being described is that the newer LED lights (QBs) are very intense. Intense lighting increases the plants nutrient needs. That’s simple enough right? Not hard to understand, but in combination with low temperatures the plant doesn’t drink much/as much. Well if the plant isn’t drinking then it’s not getting nutrients either since the primary route of nutrient uptake is through the root zone with water uptake. So the plant uses up its stored systemic nutrient reserves while transporting in a minimum, insufficient amount of new nutrients due to low water uptake. This causes the deficiencies we are seeing. Whereas some other types of lighting either don’t hit the instensities LEDs do (T5s, CFLs) or if they are capable of equal par output it is in combination with higher heat output that keeps water uptake and thereby nutrient uptake moving along.

Im not saying this is exactly right, but I’m betting getting ambient temperatures up to 85 degrees or so will mostly eliminate this problem, like some have suggested in this thread.

I just got a 3x3 with a HLG 550 Rspec slammed in there. I had it running at 75w, gave them three or four days and bumped it to 125w at probably 20”, they seriously disliked it. Backed it off to 105 and they aren’t happy still. Intervien yellowing. Ironically enough a few are showing burnt tips though too like the feed is too high, but yet clear magnesium deficiencies.

Tonight I’m going to raise the light to max height, even if it’s 4’ above, then I’m going to bump up the dimmer a bit, maybe to 125w-150w and set my AC infinity controller to exhaust only when needed at 85 degrees to get the temps bumped up. I’ll probably give them a Epsom foliar at 6g/liter tonight then, and look to transplant them into a fresh mix in a week or two.

I’ll mix up the new soil tonight so it has a few weeks to “cook”. Probably go light in overall nutes but high on cal mag.

My final flowering pots are 3.9 gallon, so I’m thinking 1/2 cup of amendments per pot, not including the lime and azomite.... on a base of promix bx and 20% EWC. I’ll use 2 TBS/gal dolomite and 1 TBS/gal azomite.

The 1/2 cup amendments will be equal parts crab shell meal, neem meal, kelp meal and Epsoma tomato tone.

There will probably be about 3 actual gallons of base soil mix per pot. Sounds about right? Running DJs Flo and BB and i have bio bizz bloom for mid to late flower supplementation if needed.

Anyone seeing anything grossly out of whack with my soil mix?

 

[Koondense]

A tip for organic growers.
Some plants have the described issues under leds but some don't, i had some in veg and one in particular has the tendency to fade(selfed line), after making some aerated compost tea she bounced back unexpectedly, the soil life seems to help tremendously.

Just a note.



Cheers

 

[Brother Nature]

I’m having the same issues as everyone else. Organic soil grower that has zero issues under hps, now switched to LEDs and I have issues in veg, mostly I’m able to iron things out by flower with going extremely low on the dimmer. After reading through this thread, I’m convinced it’s temperature related. The LEDs run so cool my tent is at 76F, and come to think of it by the time I switch to flower they are able to handle more light which increases the temps in there.

I guess it makes sense if you think about it in simple terms. What I’m hearing being described is that the newer LED lights (QBs) are very intense. Intense lighting increases the plants nutrient needs. That’s simple enough right? Not hard to understand, but in combination with low temperatures the plant doesn’t drink much/as much. Well if the plant isn’t drinking then it’s not getting nutrients either since the primary route of nutrient uptake is through the root zone with water uptake. So the plant uses up its stored systemic nutrient reserves while transporting in a minimum, insufficient amount of new nutrients due to low water uptake. This causes the deficiencies we are seeing. Whereas some other types of lighting either don’t hit the instensities LEDs do (T5s, CFLs) or if they are capable of equal par output it is in combination with higher heat output that keeps water uptake and thereby nutrient uptake moving along.

Im not saying this is exactly right, but I’m betting getting ambient temperatures up to 85 degrees or so will mostly eliminate this problem, like some have suggested in this thread.

I just got a 3x3 with a HLG 550 Rspec slammed in there. I had it running at 75w, gave them three or four days and bumped it to 125w at probably 20”, they seriously disliked it. Backed it off to 105 and they aren’t happy still. Intervien yellowing. Ironically enough a few are showing burnt tips though too like the feed is too high, but yet clear magnesium deficiencies.

Tonight I’m going to raise the light to max height, even if it’s 4’ above, then I’m going to bump up the dimmer a bit, maybe to 125w-150w and set my AC infinity controller to exhaust only when needed at 85 degrees to get the temps bumped up. I’ll probably give them a Epsom foliar at 6g/liter tonight then, and look to transplant them into a fresh mix in a week or two.

I’ll mix up the new soil tonight so it has a few weeks to “cook”. Probably go light in overall nutes but high on cal mag.

My final flowering pots are 3.9 gallon, so I’m thinking 1/2 cup of amendments per pot, not including the lime and azomite.... on a base of promix bx and 20% EWC. I’ll use 2 TBS/gal dolomite and 1 TBS/gal azomite.

The 1/2 cup amendments will be equal parts crab shell meal, neem meal, kelp meal and Epsoma tomato tone.

There will probably be about 3 actual gallons of base soil mix per pot. Sounds about right? Running DJs Flo and BB and i have bio bizz bloom for mid to late flower supplementation if needed.

Anyone seeing anything grossly out of whack with my soil mix?

Your mix seems good. What are your relative humidity levels in the room? I'd also have a look at the rate of air circulation.

 

[OZZ_]

Your mix seems good. What are your relative humidity levels in the room? I'd also have a look at the rate of air circulation.

RH is around 50-60%. As for air circulation, as in to much circulation or not enough?

 

[Grapefruitroop]

Tonight I’m going to raise the light to max height, even if it’s 4’ above, then I’m going to bump up the dimmer a bit, maybe to 125w-150w and set my AC infinity controller to exhaust only when needed at 85 degrees to get the temps bumped up. I’ll probably give them a Epsom foliar at 6g/liter tonight then, and look to transplant them into a fresh mix in a week or two.

Yup ...raise light....raise temps...raise ppms...
6g x Liter seems a bit much IMO....i always supplement 1g x gal if soil drench or 3g x gal foliar (this will ad more or less 75ppm Mg)
Also The ACT input will make things move faster like Koondense said.

I solved all the problems switchin to no nutes in the mix and feeding a well balanced formula like Megacrop by the ppm....no more ghost problems...no more guessing...just "little bit more or little bit less"

 

[OZZ_]

Yup ...raise light....raise temps...raise ppms...
6g x Liter seems a bit much IMO....i always supplement 1g x gal if soil drench or 3g x gal foliar (this will ad more or less 75ppm Mg)
Also The ACT input will make things move faster like Koondense said.

I solved all the problems switchin to no nutes in the mix and feeding a well balanced formula like Megacrop by the ppm....no more ghost problems...no more guessing...just "little bit more or little bit less"

Thanks Grapefruit- I did list all of that, raised the light and raised the temps, but also put them straight into a richer soil mix and it worked wonders. They are growing fantastically.

 

[Green81]

Subbed. LEds will be a steep learning curve for me. Has anyone have experience with the new led gravitas in regards to feeding and light distance?

 

[OZZ_]

I think I’ve got all my issues sorted out. Several lessons that have been mentioned already here and elsewhere but are easy to overlook and are very important IMO.

1) Keep that light raised high and let them grow into it. Dimming it down and having it close does not work out as well as having it turned up with more power but raised higher. As in I started the plants below (see pic) at only 75w @ a full 36” when they were transplanted at 10” tall, increased slowly to 100w, then 150, 200, 250 and now at 300w. Flipped them to flower four days ago or so, will keep it here until they see beginning bud development then will up it slowly to 400w and keep it there (it’s a 550rspec in a 3x3). Currently at 300w week one of flower still at 30” away and they are doing fine.

2) Definitely lots of cal/mag. Specifically magnesium. I’m using full strength cal/mag @ 5ml/gal with RO water and on some plants STILL seeing that they are barely trying to display intervein striping; foliar spraying with a high Epsom salt concentration at 6g/liter once per week (yes very high) is keeping it at bay. I may consider adding some Epsom directly to my soil next time around, will need some experimenting.

3) Temperature. Needs to be in the 80 deg range. LEDs run cool, when temps where in the 70’s they didn’t do well at all, raised the light higher, increased the lighting intensity which increased temps and they are taking off.

4) all this requires FOOD. They definitely have an increase metabolism when all of the above are implemented. But it needs to be balanced Nutrition. I’m a soil grower and my soil mix that has worked for years under HPS, (a tried and true supersoil mix) they didn’t seem to like. I scraped it and now went with straight FFOF with lime added, 4 heavy spoonfuls to a 3.9 gallon pot of FFOF and extra chunky perilite and all is well.

I will go back to a supersoil, but I needed to rule some things out as per the recommendations in this thread. Next supersoil will have a full 1/3 of worm castings. I think more humus is necessary, the 20% I was using before with lots of amendments wasn’t cutting it. I’m sure it was simply a weakness in my soil mix that was always there but just didn’t show due to lower metabolism under HPS.

This pic was taken day one of 12/12. A bit of a test run. I have now noticed adding 20% tap water to my RO + cal/mag water has seemed to stop the need for magnesium foliar.... atm. We will see if this solves it. My tap is very high PPM with a PH around 7.8-8.2. Mixed with RO at 20% Im getting around 6.4-6.8. Seems to be working.

I think all these things need to be in place, in order of importance. #1 keep that light high. #2 lots of cal/mag/minerals. #3 Temperature #4 rich well balanced soil W/ lots of humus (if growing in soil).

 

[f-e]

I read N&K push each other out. I see that while my N levels have needed some increase, I can no longer us K additives. I have been logging the onset and progression of brown hairs. Finding that K just kills them off early. My last run saw the first hairs go at 27 days and the 20% point reached around day 36 using no K boost. The run before a transitioned from P to K at very mild levels at 12 days, with a real dose of K at day 22. By day 26 I had the first brown hairs and a little tip burn and 30% brown on some plants by day 28. At day 36 is was 90% browned off. Yet feed had been going in around ec1.1 and run-off was ec1.5 so nowhere near toxic. The run before that the first hairs turned at day 24.

There is no doubt that the browning off comes with hardening up. Their is also stunting though which leads to an early finish. Too early. Like nothing happened from week 6, at all. I have never seen K have such an effect.

I might be missing some vital ingredient to go along with the K but it's not P as this all started with PK doing it.

Calcium needs remain high. Also Mg but that's typical for me anyway.

I'm having some isolated issues. Same faults in the same parts of my space. Might be temperature swing. It's for another thread.

 

[eyesdownchronic]

If you are having Cal:mag issues when switching from HID to LED's the problem does not stem from the nutrient solution you are giving. It has to do with the decreased heat output from the led's. It seems that led's also dissiapte less humidity from the air, so they gernerally run at a higher RH. Temp's + humidity drive transpiaration, so when your temps go down and humidity up your plant can not take up as much water. Since calcium and magnesium are both taken up through bulk flow of water, even if enough of the nutrients is in soil or solution, the plant is not able to take them up. This is similar to tomato growers running into blossom end rot (Ca. def.) the response is to increase air flow, not add more Ca. Other nutrients such as N or P can be take up via root diffusion so the lack of water uptake has a smaller effect on nutrient uptake of these elements.