Unstoppable mag deficiency under LED

[Waira]

...thanks bud! How much a defc. damaged leaf can recover depends a lot on severity and the specific nute' in question; for example, yellowing from Fe defc. can be largely reversed,... yellowing/spotting from Ca will not; I think sometimes, beyond a certain point, an affected leaf is considered a "write-off" by the plant, and so she'll continue to drain the last goodies out of it before it gets shed,.. this can make it appear that the defc. is still raging unchecked! Best always, to look at the newer/less impacted leaves to watch for further advancement or halting of symptoms!
>> lock-out isn't an on or off switch, but progression in relative availability--- scope out this chart; see how the bars' width attenuates up and down, according to relative availability?

----> so, the nice bright green color is typical of new growth, but if they don't darken up as they mature and new growth gets more and more pale as it grows and becomes a blemish-free even yellowing, that's very likely Fe defc.,.... check this nice sticky thread out- https://www.autoflower.org/f74/self-diagnose-your-plants-basic-deficiencies-list-11.html
....Water situation sounds good! You're doin' it right- *** Hardness and alkalinity are intimately related: hardness tells you how much dissolved solids are in the water (largely Ca and Mg carbonates), measured usually in ppm's; alkalinity measures the waters capacity to buffer acid, which is done by the mentioned carbonates; tap usually has plenty of hardness, but RO/DI has none, and so without the carbonates in there, it's prone to wild swings in pH from very small inputs! .....

 

[tiddlesman]

Something I've learned while trawling the internet for information on growing -

When it comes to nutrient in any medium, you end up with lockout because of an imbalance. The imbalance can be due to a variety of reasons: PH too high or too low, deficiencies, or toxicities.

You have signs of a deficiency, but it seems that you are unable to remedy it with even copious amount of the correlating nutrient? You're either wrong about the deficiency, or it could also be because of:

Some different elements/chemicals use the SAME pathways through the one plant, so if you have too much of one - it will block up those pathways and the other nutrient won't get absorbed - thus creating a deficiency.

Try backing off all your feeding, look into magnesium and how it works as a plant nutrient. I'm sure you'll pull through.

GL.

 

[dirty budster]

I use GN06, hesi, rhizo and Plagron and I do not see any other reason for your troubles as DL. We both water with ph 6,5 water, you have troubles, I have wonderfull plants, all green. We do everything very similar, except I use only half teaspoon of DL in 18l of soil, just because I do not get proper calmag here around, and that is exactly 1/30 of what you had used.

That's interesting how our setups are nearly identical with completely different results. Unfortunately I don't think it's as simple as too much DL because I had very similar issues last grow, with the MG def that is, and that was without DL. It was actually the reason I decided to add it this grow. Next grow I will use less or non at all as I haven't really seen any benefits.

...thanks bud! How much a defc. damaged leaf can recover depends a lot on severity and the specific nute' in question; for example, yellowing from Fe defc. can be largely reversed,... yellowing/spotting from Ca will not; I think sometimes, beyond a certain point, an affected leaf is considered a "write-off" by the plant, and so she'll continue to drain the last goodies out of it before it gets shed,.. this can make it appear that the defc. is still raging unchecked! Best always, to look at the newer/less impacted leaves to watch for further advancement or halting of symptoms!
>> lock-out isn't an on or off switch, but progression in relative availability--- scope out this chart; see how the bars' width attenuates up and down, according to relative availability?

----> so, the nice bright green color is typical of new growth, but if they don't darken up as they mature and new growth gets more and more pale as it grows and becomes a blemish-free even yellowing, that's very likely Fe defc.,.... check this nice sticky thread out- https://www.autoflower.org/f74/self-diagnose-your-plants-basic-deficiencies-list-11.html
....Water situation sounds good! You're doin' it right- *** Hardness and alkalinity are intimately related: hardness tells you how much dissolved solids are in the water (largely Ca and Mg carbonates), measured usually in ppm's; alkalinity measures the waters capacity to buffer acid, which is done by the mentioned carbonates; tap usually has plenty of hardness, but RO/DI has none, and so without the carbonates in there, it's prone to wild swings in pH from very small inputs! .....

Thanks again for the hints Waira, it's much appreciated.

Something I've learned while trawling the internet for information on growing -

When it comes to nutrient in any medium, you end up with lockout because of an imbalance. The imbalance can be due to a variety of reasons: PH too high or too low, deficiencies, or toxicities.

You have signs of a deficiency, but it seems that you are unable to remedy it with even copious amount of the correlating nutrient? You're either wrong about the deficiency, or it could also be because of:

Some different elements/chemicals use the SAME pathways through the one plant, so if you have too much of one - it will block up those pathways and the other nutrient won't get absorbed - thus creating a deficiency.

Try backing off all your feeding, look into magnesium and how it works as a plant nutrient. I'm sure you'll pull through.

GL.

Welcome to the forum tiddlesman. One reason for adding so much nutes is that the pots are still taking 6 days to dry out so I'm essentially only feeding them once a week. Normally I would be feeding them 2-3 times a week. I'm not completely sure why they take so long since the humidity is around 40% and temperature is 26-27C or 79-81F.

They grew a good amount in the 2-3 days after the feeding but now they've slowed down again. I take that as a sign that they like what they're getting but it's no quite enough. I did an another slurry test today. I dug out some soil a few centimeters down and mixed it with some water and measured the pH to 6.65 so it looks like it's coming down. I guess that should make an Fe deficiency less likely. I snapped some close-ups today of CBD1 in the lower left corner as that has been mostly affected by these issues. To me it still looks like Mg def, perhaps in combination with Fe. I could be wrong though, please correct me if I am.
I've seen recommendations of as much as 1 tbsp (15ml) epsom salt per gallon of water to treat Mg def so I might go up to 2 tsp (10ml) next feeding.

I'm still seeing intraveinal chlorosis. I also noticed that the stems on the side shoots have turned purple. I know that can be a genetic trait as well but it could also be a sign of Mg def as far as I read.

On this leaf the tip has turned a light brown.

 

[Gonzo]

That's interesting how our setups are nearly identical with completely different results. Unfortunately I don't think it's as simple as too much DL because I had very similar issues last grow, with the MG def that is, and that was without DL. It was actually the reason I decided to add it this grow. Next grow I will use less or non at all as I haven't really seen any benefits.

Yes, very similar setups, so the results must be very similar.

If it is not DL fault, then you put something else inside soil that is not ok, because Plagron does not make any problems or ph issues.
I went back to your grow from the beginning and you say you make your soil ph 6,8. I did not know that before. What is the idea of that?

I use only pure Plagron with half tsp of DL but that is not meant for first weeks, neither to interfere with soil ph. I do not water Plagron before planting (must be fresh from bag to do this way), add only 100 ml of dechlorinated tap water after putting sprouted seeds inside, water is hard and alkaline itself, ph corrected with Hesi ph down (nitric acid). After three days I give them 150 ml water with rhizo 1ml per litre, ph adjusted to 6,5. And so on, but mostly I keep them dry enough. If there is very little water in Plagron initially, roots can speed up through airy and light peat. On the way they find all food they need to stay completely green without any intervention. Only moisting if dry.

After ten days (when your defficiencies start to show), my plants look all green and healthy. Today I have checked all of them thoroughly with magnifying glass for any signs of defs but could not find any. I found an aphid instead. Only one, what means very soon. Tomorrow I will spray all of them.

I can not help you with saving your recent grow, but for the next try I really recommend you to eliminate everything that is not proven in this very setup. Seems that you make a mistake or two in preparing Plagron or in the very first days and seems that your troubles are ph related.

Good Luck!

 

[dirty budster]

Thanks for the hints Gonzo. I didn't intentionally make it 6.8. It was 6.8 when I measured it, most likely due to the dolomite lime. I did pre-water the pots with a bit of root stim a couple of weeks in advance. It might have been too wet still when I put the seeds in. I will skip that next time and see how that goes. I won't be using Plagron next time because they didn't have any at the shop so I will be using Atami light-mix instead.
The strange thing is I did two grows in the same way but under CFL and didn't have any troubles. Looking back at the pictures I could see there was a hint of Mg def initially but it went away once I started adding the base nutes. I didn't even use any cal-mag. I started having these troubles when I switched to LED and as far as I know it was the only change I made.

 

[Torched]

I'm concerned about you using so much nutes and it taking 6 days for your soil to dry out. My thought on this is when you have nute burn on your leaves you are getting similar damage to your roots. If the cycle continues your roots keep getting damaged and because they are damp, root rot can set in. When I first switched to LED I killed a few young plants because I couldn't rightly tell damp from dry under the pink light and cooked them at normal temps.

Can you mount a small fan at soil level?
Water with 1/2 as much water at normal nutrient levels, hopefully it dries out in 3 days.

At this point I personally would ease up on everything. Stick with normal levels of base nutrient, recommended normal cal/mg dosage, and nothing else.
A slurry ph reading of soil is not super accurate so it's possible your PH is off from what you think it is. Then wildly throwing all sorts of things to correct the problem can cause other problems. A pause will give your soil/plant time to stabilize. If you have mycos or compost tea available it may help with the soil working it's self out.

Knowing your lime will buffer the nutrients it might be wise to lower the PH of what you are feeding a couple points, to compensate.

 

[dirty budster]

Thanks Torched, using less water might be a good idea, I will try that next feeding. I dropped the pH of the feed already. I'm feeding at pH6.2. I have 2 circulation fans in there but so far I've only been running one of them. I will turn on the second one and see if that helps a bit.
As for the nutes, I'm thinking about cutting the cal-mag and using only epsom salts as I'm still only seeing Mg def I'm wondering if there's too much calcium already preventing Mg uptake.

I flipped them over to 12/12 2 days ago and they seem to be doing ok at the moment, except for a bit Mg def.

Day 46/3

Looks like there is a decent amount of bud sites so I think it might work out if I can just manage to stop the Mg def.

 

[dirty budster]

Day 53/10

Final update, after two feedings with 2 tsp/gallon of epsom salts the Mg deficiency has been resolved. All the new growth is greening up nicely and they're stretching quite a lot. I've been watering with less water so that they dry out faster and I can feed them regularly. It's still taking 4 days for them to dry out but I think that will be less now that they're bigger. Now I just have to find a way to spread the tops out evenly across the screen and then I should be good for some budding.

I snapped a couple of pictures today of the progress so far.

Thanks again for all the inputs and discussions!

 

[Waira]

Lookin' really phat in there DB!! :dance2:....nice job dialing things in- :thumbs: You're gonna have a juicy harvest, mate!

 

[dirty budster]

Thanks Waira, much appreciated! I think if the rest of the grow goes well this will be my best one to date. Really curious to see what the rebel light can do under the right conditions.