Fan leaves gone crispy, burn or deficiency???

RubeGoldberg · Jul 20, 2011

naw, at approx 700ppm nothing would look that bad,

they were getting enough nutes for sure, seems like some mysterious x factor caused a lock out.

something caused by the daily irrigation seems like the likely culprit.

poindexterous · Jul 21, 2011

I guess overwater seems to be the top candidate? Still surprising with all the perlite in there, and that in veg they thrive with frequent waterings, but what else could it be? I'm gonna hope that's the cure next round, thanks for the input!

RubeGoldberg · Jul 21, 2011

not so much overwatering, but maybe root rot or some kind of pathogen? you mentioned the roots came apart easily, how'd they look? can you post pics?

michigan.mmma · Jul 21, 2011

budlover123 · Jul 21, 2011

when was the last time the medium got a good flush? When my friend has problems he generally just flushes the shit out of them in a tub and feeds them directly after when the medium is nice and clean, it works great. If it's been over a month, salt build up lockout is entirely possible imo

of course if you think you are drowning the roots, wait until it dries out first, and if things start getting really bad, turn the pot on it's side to let some dirt out and air in

did you test the runoff for ppm's for that salt test, is a salt test an accurate indication? My friend uses GH flora nutrients and regular top soil amended with vermiculite and perlite and his salt build up is like clockwork, once a month, usually the first flush is only after about 3 weeks for some reason (maybe he should flush before he plants the seed?)

Snow Crash · Jul 21, 2011

Sorry to get to this party late, but I could have definitely ruled out Root Aphids and Phosphorus deficiency a long time ago.

You have what looks like a very typical heat issue. The interveinal chlorisis, as well as complete necrosis of the vegetative mass from the margins inwards, indicates a cation deficiency; namely in Potassium and Magnesium. Adding more of these elements would have likely not solved the issue.

As light beats down on the leaves the plant is using the photons to knock electrons off of elements so that the plant has energy it can use. This energy must be transported from the site of generation to the place it can be used. If there is an insufficient mobility of energy within the plant then the energy simply burns up the "power plant" that made it.

To keep cool the leaves use Potassium to help transfer moisture for transpiration. If there is an insufficient presence of this element the leaf cannot maintain a healthy temperature and it burns up.

Thus, by reducing the temperatures in the grow space the leaf would have been able to manage the heat that ultimately resulted in necrosis. It is astounding to me that not a single person asked you what your canopy temperatures are while they beat the whole RA thing to death. In addition to dropping canopy temperatures it was definitely wise to reduce your EC levels. I think that running less food all together would have provided less competition for uptake of K+ and Mg++ and may have helped reduce the severity of the heat stress. I have used Liquid Karma in the past which helps alleviate the issue to a minor degree.

If heat is not an issue then the only other explanation I can offer for the cation imbalance would be the presence of higher than expected levels of Sodium in your nutrient system or water supply. Also, too much Calcium in flowering (especially in a media that has retained a buffer of the element like coco) will compete for uptake with these other elements. Also, Calcium Sulfate can precipitate if you have been using a very alkaline Potassium Silicate supplement after adding Epsom Salt. This precipitate can cause issues.

How I respond to this issue in my own garden is to apply a K-Mag dominant Foliar spray during lights on several times per week. I will also work to reduce my temperatures to consistently fall between 74 degrees and 78 degrees, working to stay as close to 75.6 degrees as possible. When following these steps, while applying higher than normal levels of solution to get a good volume of runoff every time, I always resolve the issue.

Here's a picture (sorry about the white balance) of a plant with fan leaves that had started to go south the same way that yours were but that I managed to save with a foliar spray. You can see the yellowing from the initial burn up of the chlorophyll but also notice the "blotchy" green of what was saved. This is a result of the halting of the necrosis you saw in your last grow. I have dealt with this problem in Coco several times and am intimately familiar with it and its resolution.

K-Mag to the rescue!

poindexterous · Jul 21, 2011

Snow Crash said:
Sorry to get to this party late, but I could have definitely ruled out Root Aphids and Phosphorus deficiency a long time ago.

You have what looks like a very typical heat issue. The interveinal chlorisis, as well as complete necrosis of the vegetative mass from the margins inwards, indicates a cation deficiency; namely in Potassium and Magnesium. Adding more of these elements would have likely not solved the issue.

As light beats down on the leaves the plant is using the photons to knock electrons off of elements so that the plant has energy it can use. This energy must be transported from the site of generation to the place it can be used. If there is an insufficient mobility of energy within the plant then the energy simply burns up the "power plant" that made it.

To keep cool the leaves use Potassium to help transfer moisture for transpiration. If there is an insufficient presence of this element the leaf cannot maintain a healthy temperature and it burns up.

Thus, by reducing the temperatures in the grow space the leaf would have been able to manage the heat that ultimately resulted in necrosis. It is astounding to me that not a single person asked you what your canopy temperatures are while they beat the whole RA thing to death. In addition to dropping canopy temperatures it was definitely wise to reduce your EC levels. I think that running less food all together would have provided less competition for uptake of K+ and Mg++ and may have helped reduce the severity of the heat stress. I have used Liquid Karma in the past which helps alleviate the issue to a minor degree.

If heat is not an issue then the only other explanation I can offer for the cation imbalance would be the presence of higher than expected levels of Sodium in your nutrient system or water supply. Also, too much Calcium in flowering (especially in a media that has retained a buffer of the element like coco) will compete for uptake with these other elements. Also, Calcium Sulfate can precipitate if you have been using a very alkaline Potassium Silicate supplement after adding Epsom Salt. This precipitate can cause issues.

How I respond to this issue in my own garden is to apply a K-Mag dominant Foliar spray during lights on several times per week. I will also work to reduce my temperatures to consistently fall between 74 degrees and 78 degrees, working to stay as close to 75.6 degrees as possible. When following these steps, while applying higher than normal levels of solution to get a good volume of runoff every time, I always resolve the issue.

Here's a picture (sorry about the white balance) of a plant with fan leaves that had started to go south the same way that yours were but that I managed to save with a foliar spray. You can see the yellowing from the initial burn up of the chlorophyll but also notice the "blotchy" green of what was saved. This is a result of the halting of the necrosis you saw in your last grow. I have dealt with this problem in Coco several times and am intimately familiar with it and its resolution.

K-Mag to the rescue!

Hey Snow, thanks for the info, canopy temps certainly reached 85 often, maybe even close to 90 intemittently, I thought with CO2 it would be ok but perhaps not. So I'll reduce temps for sure along with water frequency. Do you think adding cal-mag is a bad idea then since I'm in a peat based mix? I always water to a decent runoff so I wouldn't think salts were building up. What ppm would you think ideal for my pro-mix perlite blend?

Crush · Jul 22, 2011

RubeGoldberg said:
really looks like a burn though considering it started at the tips.

Yup that's what my guess is. Complete nute burn and lockout.

If growing in soil, don't feed nutes every watering.

But you still can get great bud and smoke so no worrys there.

poindexterous · Jul 22, 2011

Hmmm, alternating nutes and plain water every other feeding would sure be a pain for an automated top feed system, surely a low enough ppm could be used for every watering, I let it water to a good runoff every time so they get flushed well. Just hard to accept nute burn at 500ppm.

As far as the root system I broke apart a few root masses and they were nice and white no sign or smell of any rot or slime, pro-mix still nice and loose with all the extra perlite.

A friend of mine uses straight pro-mix without any extra perlite, top feeds twice daily at 1000ppm, and has no such issues, which is why over-nutes and overwater is hard to accept.

So between Nutrient burn, Media too wet, or heat stress, I lean towards heat even though I could swear past rounds were as warm. Maybe my current strains can't handle occasional upper 80's temps?

Core · Jul 22, 2011

i think its nutrient burns.... :2cents:

MIway · Jul 22, 2011

poindexterous said:
Hmmm, alternating nutes and plain water every other feeding would sure be a pain for an automated top feed system, surely a low enough ppm could be used for every watering, I let it water to a good runoff every time so they get flushed well. Just hard to accept nute burn at 500ppm.

As far as the root system I broke apart a few root masses and they were nice and white no sign or smell of any rot or slime, pro-mix still nice and loose with all the extra perlite.

A friend of mine uses straight pro-mix without any extra perlite, top feeds twice daily at 1000ppm, and has no such issues, which is why over-nutes and overwater is hard to accept.

So between Nutrient burn, Media too wet, or heat stress, I lean towards heat even though I could swear past rounds were as warm. Maybe my current strains can't handle occasional upper 80's temps?

If you had some heat stress, the new growth fringes of the leaf blades would be sticking upwards... but you have necrosis from the older leaves moving up... and otherwise healthy new growth. That's an indicator of a major macro issue.

If you fried the plants, you would see multiple nute issues, and likely a hooking of the new growth leaves, which isn't there. Along with practical stopping of all new growth. I only really see the P issues.

If you had small pots with big plants, then the frequency of the watering might be as high as twice per day. But if you had larger pots, even with large plants, you could pretty easily get away with a x1 feed every other day. If it's in balance (healthy), you'll definitely get a strong root mass that will be wrapping around the soil within the pot, which you didn't get. Promix needs to dry out a bit.

Bro... it all points to soggy soil. Which fits with the watering plan you outlined. Super common... giving the plant too much love. Peace brother.

poindexterous · Jul 22, 2011

MIway said:
If you had some heat stress, the new growth fringes of the leaf blades would be sticking upwards... but you have necrosis from the older leaves moving up... and otherwise healthy new growth. That's an indicator of a major macro issue.

If you fried the plants, you would see multiple nute issues, and likely a hooking of the new growth leaves, which isn't there. Along with practical stopping of all new growth. I only really see the P issues.

If you had small pots with big plants, then the frequency of the watering might be as high as twice per day. But if you had larger pots, even with large plants, you could pretty easily get away with a x1 feed every other day. If it's in balance (healthy), you'll definitely get a strong root mass that will be wrapping around the soil within the pot, which you didn't get. Promix needs to dry out a bit.

Bro... it all points to soggy soil. Which fits with the watering plan you outlined. Super common... giving the plant too much love. Peace brother.

The pots they were in were pretty big compared to the plants size, more so than I'd done in the past, so maybe you're right. Thanks for the further input my friend!

poindexterous · Jul 22, 2011

Core said:
i think its nutrient burns....

I'm happy to lower ppm, just don't want to go too low, next round gonna stick with 500ppm and see how it does. Shouldn't be deficiencies at 500.....right?

Core · Jul 23, 2011

mmmh 500 ppm 's for full flowering plants is a bit to low imo...bump it to 800 a 900

poindexterous · Jul 23, 2011

Core said:
mmmh 500 ppm 's for full flowering plants is a bit to low imo...bump it to 800 a 900

Yeah that's what I would think. Thus I've been doubting my leaf symptoms were nutrient burn as I never exceeded 1000ppm with the plants pictured above. Gotta be either overwater or heat stress, gonna be careful with both this time.

budlover123 · Jul 25, 2011

poindexterous said:
... I let it water to a good runoff every time so they get flushed well...

I'm not talking about runoff, I'm talking about a big, propper flush, like 3 gallons through a 1 gallon pot, etc.

poindexterous · Jul 25, 2011

I'll certainly do that for this new round.

fishwipe · Jul 29, 2015

Poindexterous - It's been a while now… did you ever discover what was causing the problem? Reason I ask is because I have EXACTLY the same thing… I'm growing in perlite/vermiculite - but I had the same when I was using coco...

Mustarastas · Nov 24, 2015

I got the same problem. im using only soil nothing mixed with it. i got the same crispyness after i started usin gh flora trio nutrients so i think good flush would help. it started immidiatly when i gave first feed or do u have any solution to this problem?

ps. sry my english

Mustarastas · Nov 24, 2015

its the nutrients i got the same problem but it started when i gave them theyr first feed about 3.5 weeks into veg. i think if u give feed.water.water.feed that would help or feed.water.feed atleast i will try this

Fan leaves gone crispy, burn or deficiency???

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