LEDs causing magnesium like issues

[MercDod]

Awesome! I appreciate you putting this together for me. As far as ph goes I’m putting in 6.5 and 6.0 is coming out the bottom. The opposite as you described. I haven’t added lime to what’s already in the mix in a few years so it shouldn’t be that. Even though my room is 84 degrees I’m wondering if the pots are still too cold. Still pretty extreme if that’s the case.

One more quick look at this link

Potassium Deficiency in Hemp Cultivation: Impact and Prevention

Growing hemp can be subject to various challenges, one of the most common of which is potassium deficiency. This deficiency can have a significant impact on plant health and crop quality. Potassium deficiency often manifests itself as yellowing of the leaf edges, while the main veins remain...

cbxmedical.com

 

[amneziaHaze]

View attachment 2600317View attachment 2600318View attachment 2600319
This is at its worst. I recently built a new veg room and struggled getting it to the same parameters as the last area. My truncheon meter was reading super low at the same time and I didn’t know it. I thought that was the solution to my problem so I went down to 1.4 ec and they got really bad. They seem to be getting better now but it’s a ton of work. The issue is always just trying to rear its ugly head.

Thats not mg def. Mg starts at bottom not the top

 

[Ninjadogma]

Thats not mg def. Mg starts at bottom not the top

It'll also happen in the mid plant when the soil is out of whack or the light is stripping it out, but it doesn't look like that. With mag the pleats get light, not the edges. Interveinal Chlorosis is the nerdy term. With the edges its usually potassium, and when it happens mid plant like that, it almost always signals EC stress. Those salt pockets can hide I tell ya... you think you got it all and 3-4 waterings later you're still hitting pockets. Especially with a coco peat blend. It can take a minute to figure out what's going on but once it clicks, you can fix the plant, get it back on track and chalk it up as experience to keep in your rearview mirror.

You know those cool shots of mid stage flowers looking dank and throwing those yellows and purples they call senescence? That's salt, not senescence. Senescence works it's way up from the bottom, just like you originally mentioned about mag.

 

[amneziaHaze]

It'll also happen in the mid plant when the soil is out of whack or the light is stripping it out, but it doesn't look like that. With mag the pleats get light, not the edges. Interveinal Chlorosis is the nerdy term. With the edges its usually potassium, and when it happens mid plant like that, it almost always signals EC stress. Those salt pockets can hide I tell ya... you think you got it all and 3-4 waterings later you're still hitting pockets. Especially with a coco peat blend. It can take a minute to figure out what's going on but once it clicks, you can fix the plant, get it back on track and chalk it up as experience to keep in your rearview mirror.

You know those cool shots of mid stage flowers looking dank and throwing those yellows and purples they call senescence? That's salt, not senescence. Senescence works it's way up from the bottom, just like you originally mentioned about mag.

Yup hunger allways starts at 5he bottom or any leaf thats in the shadow gets sacrificed first

 

[MrSativa]

I don’t remember all the details but I think it was something about the reflective material on the inside. It was off gassing some toxic chemicals.

Exactly ! this showed back then the same yellowing that you have , starts aafter 4 weeks Nutes/Watering is 100% correct co2 is correct.

If this continues it wil look like a pk 13/14 burn if that is so not only watch out for your plants but mainly yourself!

 

[MercDod]

Thats not mg def. Mg starts at bottom not the top

Your right, its potassium deficiency and typically starts on older leaves and starts on leaf margins as in your photo. Just a thought.

 

[BaldrickTX]

I have them raised up on saucers that catch runoff. 2-3” off the ground. Maybe that’s not enough? I learned a long time ago not to put pots directly on concrete. Cool roots could be possible but with room temps at 84 degrees is seems unlikely.

I was having issues with my roots being too cold, and about a month ago I finally was able to do something to address this problem.
It would be 77° in my tent, my plants were off the ground, the water temperature that I fed them was about 78° and yet the temperature of the soil, about 8" deep, read 60°.
I found some Vivosun heating mats that are 48" x 20.75" and so far my root temps are where I want them and my plants are responding nicely.
Just my two cents worth.

 

[Tattooguy8]

Thats not mg def. Mg starts at bottom not the top

Yep. More of a potassium issue. Also resembles a mag issue at times is all that was implied. Also showing lots of purple. This is a nutrient uptake issue. Plants can’t keep up with how hard the lights are driving them even though the ppfd is at 180.

 

[Tattooguy8]

It'll also happen in the mid plant when the soil is out of whack or the light is stripping it out, but it doesn't look like that. With mag the pleats get light, not the edges. Interveinal Chlorosis is the nerdy term. With the edges its usually potassium, and when it happens mid plant like that, it almost always signals EC stress. Those salt pockets can hide I tell ya... you think you got it all and 3-4 waterings later you're still hitting pockets. Especially with a coco peat blend. It can take a minute to figure out what's going on but once it clicks, you can fix the plant, get it back on track and chalk it up as experience to keep in your rearview mirror.

You know those cool shots of mid stage flowers looking dank and throwing those yellows and purples they call senescence? That's salt, not senescence. Senescence works it's way up from the bottom, just like you originally mentioned about mag.

This is all true but in my situation this happens at times with very fresh peat. Within a watering or two. Waaaay before the peat gets salty. I don’t believe this is any one nutrient issue. This is an overall uptake issue. Same feed, ph, watering frequency same temps same everything under a t5 in the same room even and the plants look great. Move them under the led at 200 ppfd and this happens literally overnight in some cases. Not every time and not this extreme but some version of this happens especially at lower ec values.

 

[Tattooguy8]

I was having issues with my roots being too cold, and about a month ago I finally was able to do something to address this problem.
It would be 77° in my tent, my plants were off the ground, the water temperature that I fed them was about 78° and yet the temperature of the soil, about 8" deep, read 60°.
I found some Vivosun heating mats that are 48" x 20.75" and so far my root temps are where I want them and my plants are responding nicely.
Just my two cents worth.

My room is 84 degrees but this is definitely something I’m going to investigate closer. Even though my room temps are fine I might be underestimating how cold my roots are for some reason.

 

[Tattooguy8]

It'll also happen in the mid plant when the soil is out of whack or the light is stripping it out, but it doesn't look like that. With mag the pleats get light, not the edges. Interveinal Chlorosis is the nerdy term. With the edges its usually potassium, and when it happens mid plant like that, it almost always signals EC stress. Those salt pockets can hide I tell ya... you think you got it all and 3-4 waterings later you're still hitting pockets. Especially with a coco peat blend. It can take a minute to figure out what's going on but once it clicks, you can fix the plant, get it back on track and chalk it up as experience to keep in your rearview mirror.

You know those cool shots of mid stage flowers looking dank and throwing those yellows and purples they call senescence? That's salt, not senescence. Senescence works its way up from the bottom, just like you originally mentioned about mag.

Also this most definitely effects some of the lower leaves the most.

 

[Tattooguy8]

One of the other issues I get and I believe they are fully related is extreme stretching in seedlings and younger plants under the led. I start all seedlings under a t5. Same feed, same ph, same ec, same media. I usually keep them under the t5 for around two weeks. As an example we’ll say the seedlings have 4-5 nodes and the plant is 5” tall at the end of two weeks. As soon as I move them under the LEDs they stop stacking nodes and just stretch waaaay out. In a week same plant will still have 5 nodes but be over a food tall. Instead of a half inch between all the nodes there will be 4” between all the same nodes. Obviously because of the stretching all the stems will be hollow and weak.

If I try to start seedlings under the LEDs, they will stretch so far they’ll literally kill themselves they’ll stretch so far.

I can eventually stop this from happening somewhat by topping the crap out of them a few times. I’m stumped as to why this happens.

 

[Ninjadogma]

One of the other issues I get and I believe they are fully related is extreme stretching in seedlings and younger plants under the led. I start all seedlings under a t5. Same feed, same ph, same ec, same media. I usually keep them under the t5 for around two weeks. As an example we’ll say the seedlings have 4-5 nodes and the plant is 5” tall at the end of two weeks. As soon as I move them under the LEDs they stop stacking nodes and just stretch waaaay out. In a week same plant will still have 5 nodes but be over a food tall. Instead of a half inch between all the nodes there will be 4” between all the same nodes. Obviously because of the stretching all the stems will be hollow and weak.

If I try to start seedlings under the LEDs, they will stretch so far they’ll literally kill themselves they’ll stretch so far.

I can eventually stop this from happening somewhat by topping the crap out of them a few times. I’m stumped as to why this happens.

We've discussed conventional culprits as well as some very unconventional ones (tent gas). You mention you see the issue show up around the time you're moving them from a t5 to led. I don't think your LED light is causing the issue, I think it's exposing it. You flipped an energy switch on, the plant suddenly has the ability to do a lot more, but struggles out the gate getting things regulated.

Something else you mentioned is it happens with fresh peat after just a couple waterings. Well, fresh peat isn't salt free and certainly can come on that quick. I take this as further confirmation of a salt problem and contrary to the advice that's usually thrown out, you need more water and a greater volume of it, but make sure you move it slowly through. Frequency we've talked about. If it's a coco peat blend (right?) then you don't want to give it drybacks, give it water when it's still got 75% of its pot weight. Then whatever volume of water you used to water, as soon as true runoff happens (not the false runoff that falls before the soil got wet), keep pouring more until about 1/5 of everything you poured in flows back out. Also when you're checking your runoff readings you dont even want to look at the initial runoff, because it's a liar. It can give you a good number while there's still dry pockets with toxic salt scattered throughout the pot. I don't know if you've ever taken a moment to directly observe soil hydrophobia, it's a head scratcher.. I mean you're looking at water sitting on dry dirt and the water just won't penetrate it. Well it actually does but very slowly, and so sometimes when you've let the pot get extra dry it's not a bad idea to water it until water runs out, come back in an hour and do it again, and the third time you are closer to being able to correctly finish watering right.

 

[GasPlease]

If I try to start seedlings under the LEDs, they will stretch so far they’ll literally kill themselves they’ll stretch so far.

What's the ppfd youre giving them with the led?

 

[amneziaHaze]

One of the other issues I get and I believe they are fully related is extreme stretching in seedlings and younger plants under the led. I start all seedlings under a t5. Same feed, same ph, same ec, same media. I usually keep them under the t5 for around two weeks. As an example we’ll say the seedlings have 4-5 nodes and the plant is 5” tall at the end of two weeks. As soon as I move them under the LEDs they stop stacking nodes and just stretch waaaay out. In a week same plant will still have 5 nodes but be over a food tall. Instead of a half inch between all the nodes there will be 4” between all the same nodes. Obviously because of the stretching all the stems will be hollow and weak.

If I try to start seedlings under the LEDs, they will stretch so far they’ll literally kill themselves they’ll stretch so far.

I can eventually stop this from happening somewhat by topping the crap out of them a few times. I’m stumped as to why this happens.

its really hard to give them too much light the lamp would be less than 15cm probably before you get problems.

 

[Tattooguy8]

We've discussed conventional culprits as well as some very unconventional ones (tent gas). You mention you see the issue show up around the time you're moving them from a t5 to led. I don't think your LED light is causing the issue, I think it's exposing it. You flipped an energy switch on, the plant suddenly has the ability to do a lot more, but struggles out the gate getting things regulated.

Something else you mentioned is it happens with fresh peat after just a couple waterings. Well, fresh peat isn't salt free and certainly can come on that quick. I take this as further confirmation of a salt problem and contrary to the advice that's usually thrown out, you need more water and a greater volume of it, but make sure you move it slowly through. Frequency we've talked about. If it's a coco peat blend (right?) then you don't want to give it drybacks, give it water when it's still got 75% of its pot weight. Then whatever volume of water you used to water, as soon as true runoff happens (not the false runoff that falls before the soil got wet), keep pouring more until about 1/5 of everything you poured in flows back out. Also when you're checking your runoff readings you dont even want to look at the initial runoff, because it's a liar. It can give you a good number while there's still dry pockets with toxic salt scattered throughout the pot. I don't know if you've ever taken a moment to directly observe soil hydrophobia, it's a head scratcher.. I mean you're looking at water sitting on dry dirt and the water just won't penetrate it. Well it actually does but very slowly, and so sometimes when you've let the pot get extra dry it's not a bad idea to water it until water runs out, come back in an hour and do it again, and the third time you are closer to being able to correctly finish watering right.

No offense but this is exhausting. I know this is an effort to help but I already do all these things. I know how to water. I’m not some one year grower. Coco isn’t salt free when it’s fresh either. I’ve experimented with runoff equaling the volume of the pot for weeks at a time. Didnt fix the issue. Again I know you are trying to help and I really appreciate it but this is all elementary stuff. Reading runoff. Who measures the first toxic amount of runoff coming out of the pot? A brand new grower? Maybe? I know this isn’t your problem so it’s probably hard to follow along. Tons of replies and scattered info in this thread so I know it’s hard to follow along. I’m in pure peat at the moment. Basically sunshine 4. I also have a few plants in pure coco as an experiment right now. I’ve used coco blends in the past.

The other myth I see being spread around the interwebs is that you can’t water coco like peat. That’s just flat out false. I personally know people that do it. I’ve seen in person, touched these plants with my bare hands. You might not get the full benefit of coco but it works beautifully. Now I’m not saying that’s the best way or the way it should be done but this myth that plants die in coco with backs is utter crap. Myths being handed down from grower to grower.

While I agree the light might just be exposing a problem and might not be the problem it doesn’t explain sprouting seedlings under 2-300 ppfd that don’t need water for the first week, ie no salt buildup, stretch and kill themselves.

I would really appreciate no more lessons on watering. Please keep in mind I used all my same techniques for over 20 years until switching to LEDs. I understand LEDs drive plants differently and blah blah blah. I also understand the reasoning no behind thinking no one knows how to water a plant, that is not the case here. If you read through any of these posts you’ll know I’ve experimented with drybacks of various amounts from scary drybacks to watering daily at full saturation. And everything in between just to be clear. The issue presents itself way too fast in fresh media regardless of what that media is.

I’m sure you know of auto pots and other similar systems. Bottom watering without runoff ever. Beautiful plants. Shit for 20 years I top watered in peat never having runoff ever for whole grows with hardly a burnt tip. I know people in my current circle who exercise this same technique as we speak in peat and under LEDs. Beautiful plants.

Again I appreciate your effort to help but this isn’t a water issue.

 

[Tattooguy8]

What's the ppfd youre giving them with the led?

2-300

 

[amneziaHaze]

No offense but this is exhausting. I know this is an effort to help but I already do all these things. I know how to water. I’m not some one year grower. Coco isn’t salt free when it’s fresh either. I’ve experimented with runoff equaling the volume of the pot for weeks at a time. Didnt fix the issue. Again I know you are trying to help and I really appreciate it but this is all elementary stuff. Reading runoff. Who measures the first toxic amount of runoff coming out of the pot? A brand new grower? Maybe? I know this isn’t your problem so it’s probably hard to follow along. Tons of replies and scattered info in this thread so I know it’s hard to follow along. I’m in pure peat at the moment. Basically sunshine 4. I also have a few plants in pure coco as an experiment right now. I’ve used coco blends in the past.

The other myth I see being spread around the interwebs is that you can’t water coco like peat. That’s just flat out false. I personally know people that do it. I’ve seen in person, touched these plants with my bare hands. You might not get the full benefit of coco but it works beautifully. Now I’m not saying that’s the best way or the way it should be done but this myth that plants die in coco with backs is utter crap. Myths being handed down from grower to grower.

While I agree the light might just be exposing a problem and might not be the problem it doesn’t explain sprouting seedlings under 2-300 ppfd that don’t need water for the first week, ie no salt buildup, stretch and kill themselves.

I would really appreciate no more lessons on watering. Please keep in mind I used all my same techniques for over 20 years until switching to LEDs. I understand LEDs drive plants differently and blah blah blah. I also understand the reasoning no behind thinking no one knows how to water a plant, that is not the case here. If you read through any of these posts you’ll know I’ve experimented with drybacks of various amounts from scary drybacks to watering daily at full saturation. And everything in between just to be clear. The issue presents itself way too fast in fresh media regardless of what that media is.

I’m sure you know of auto pots and other similar systems. Bottom watering without runoff ever. Beautiful plants. Shit for 20 years I top watered in peat never having runoff ever for whole grows with hardly a burnt tip. I know people in my current circle who exercise this same technique as we speak in peat and under LEDs. Beautiful plants.

Again I appreciate your effort to help but this isn’t a water issue.

soo what do your messurments say whats the input whats the output its easy to know if your overfeeding ec of 2.4 is not a small number and whats your ph?

 

[amneziaHaze]

No, a dark period doesn’t “help” marijuana. Marijuana doesn’t require a dark period. Now if by help you mean not hitting a plant with too much dli then yes. If you can do math you should be able to understand that 180 ppfd at 24 hours is nowhere close to “pushing” a plant.

`she doesnt require it but you will get problems after 2 weeks of 24h light it all depends on strains but i guess it helps a lot to have dark

 

[Tattooguy8]

We've discussed conventional culprits as well as some very unconventional ones (tent gas). You mention you see the issue show up around the time you're moving them from a t5 to led. I don't think your LED light is causing the issue, I think it's exposing it. You flipped an energy switch on, the plant suddenly has the ability to do a lot more, but struggles out the gate getting things regulated.

Something else you mentioned is it happens with fresh peat after just a couple waterings. Well, fresh peat isn't salt free and certainly can come on that quick. I take this as further confirmation of a salt problem and contrary to the advice that's usually thrown out, you need more water and a greater volume of it, but make sure you move it slowly through. Frequency we've talked about. If it's a coco peat blend (right?) then you don't want to give it drybacks, give it water when it's still got 75% of its pot weight. Then whatever volume of water you used to water, as soon as true runoff happens (not the false runoff that falls before the soil got wet), keep pouring more until about 1/5 of everything you poured in flows back out. Also when you're checking your runoff readings you dont even want to look at the initial runoff, because it's a liar. It can give you a good number while there's still dry pockets with toxic salt scattered throughout the pot. I don't know if you've ever taken a moment to directly observe soil hydrophobia, it's a head scratcher.. I mean you're looking at water sitting on dry dirt and the water just won't penetrate it. Well it actually does but very slowly, and so sometimes when you've let the pot get extra dry it's not a bad idea to water it until water runs out, come back in an hour and do it again, and the third time you are closer to being able to correctly finish watering right.

Also I’m not just throwing the two week old plants under 1000ppfd shredding led lights. I have to run my mom room at 250 ppfd or I have issues. They go from a t5 that’s literally one inch from the bulbs, no idea on ppfd but based on growth structure I would say it’s decent, to under the led at maybe 200 ppfd. That’s something like 15-18 dli. That’s not “an energy switch” they are just being slammed into. That’s about as low of a light you can give a plant and get acceptable growth. Now if I was Trying to slam them with just maxed out led without a clue then this would have been solved on the first page.