Yellowing and drying leaf issue

Unfortunately, I am solving the problem for the third round. As can be seen in the photos, the leaf begins to turn yellow from the edges and then dry from the edges. I use a complete series of canna fertilizers (canna hydro, rhizotonic, cannazyme, canna boost), but I have never had a problem. Water from a reverse osmosis unit. I thought it was a calcium deficiency or magnesium, so I started using a calmag agent from canna, but the problem is the same. I measure the room temperature, ph and ec of the solution. All right. I have already changed the whole brand of fertilizers, but the problem is the same. I grow from clones, but I've already changed my supplier. The problem is still there. Is it a pest or insect problem? Thank you very much in advance for saving my crop! Don't be afraid to ask me anything, I will add information. I also found some information, that it could be overwatering, but I use same schedule for some years with no problem. :-/

Is that shinyness something sprayed on the leaves ? If not an its how they are, look for signs of little tinny dents on the leaves aswell....what you may have is hemp mite which is a total bitch....try and get some closer shots please

TheDarkStorm said:

Is that shinyness something sprayed on the leaves ? If not an its how they are, look for signs of little tinny dents on the leaves aswell....what you may have is hemp mite which is a total bitch....try and get some closer shots please

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Thank you very much for your answer. I forgot to mention that the plants are already sprayed with canna cure, which is a pest control, but I'm not sure its effectiveness. Anyway, I've only been using it for a short time, about a week. Every three days. I spray before the lights go out. I took a picture of some leaves up close, maybe it will help a bit in solving the problem. Thank you very much again.



I can show you some previous sucessfull rounds:




compared to the last three rounds, which all ended in failure, I am now a very sad man

Look into Potassium def.

Before implementing any changes to your grow medium or watering solution, with those 2 HPS bulbs, you might be overheating the leaves. They will show burn symptoms even if the overall temperature is cool. Make sure you check for that first. Try turning off 1 bulb for a few days. What happens then?


What are you temps? at top of plant? at top of tent? at bottom of tent? outside tent?
What is humidity? same...


Try and get the closet picture that you can of your leaf. Also take a pic of the underside of that same leaf please.

It does remind me of a strong potassium deficiency, but yeah try to get bottom pictures of the leaves, mites are really evil and if you have them the sooner you find out the better. Also you say you measured the room, do you know the temperature/humidity/PH exactly? It can really help to narrow things down the more information available.

After searching for some information, I also thought it was a problem of potassium deficiency. But the problem will appear in growth phase, which would allegedly correspond to an overwatering. It is strange that several previous rounds were fine and now I am facing this problem for the third round. Several different genetics exchanged, but problem still persist. I'm not sure that a complete set of CANNA fertilizers would have such potassium deficiencies. In any case, according to the picture, and given the fact that the yellowing and drying of the leaves begins on older growths, this would really correspond to a lack of potassium. Thank you very much for your advice and tips. In the afternoon of my time zone, I will take a picture of the top of the leaf as close as possible and also its bottom.

I forgot to mention that I already have just one bulb burning right now because I already throw away the left side (lemon zkittle) because the damage to the plants was too high. All I have left is the right side (em dog by humboldt seeds) and I'm trying to save them and get some few from them at least.


I measure temperature in whole room also with the temperature on the top of the plants. Does not come over 26°C which is 79°F on the tops of the plant. Humidity 50-60%. pH of the feeding solution 5,9.

How often do you flush the medium with plain pH adjusted water? Could salt build up lock out some of the P?

Water the soil indoors and not the plants. Water on the leaves will cause burning under intense lights.
Outdoors, plants dry off fairly fast. But indoors, water tend to hang around too long on leaves. It can
also create mold issues later in flowering.

Too much fertilizer! You are burning them! You only need about 350 ppm or 0.7 EC. anything over could cause problems.

GoatCheese said:

How often do you flush the medium with plain pH adjusted water? Could salt build up lock out some of the P?

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Great tip. Maybe you're right. But the problem does occure even after first week of growth or so after being transplanted into a pots. There is a true, that I've flushed them little bit more often in a past. Last few rounds I flushed them only when changing nutrients from grow to bloom, then after pk13/14 week (which canna recommend add only for one week) and then 10 days before harvest. But still irrigating to get some run off - around 20%. Apparently, this run off should prevent the formation of salt. But this is great tip. I'll start to flush them for more often. Thanks for that.

troutman said:

Water the soil indoors and not the plants. Water on the leaves will cause burning under intense lights.
Outdoors, plants dry off fairly fast. But indoors, water tend to hang around too long on leaves. It can
also create mold issues later in flowering.

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I water them through the pot. Growing media is pure coco. I have automatic drip system. Irrigation approx. 5% volume of the pot which is 300ml in my case. I water them so many times as they need to get around 20% run off approx. every time. Since they're still so small, they get about 250ml 2 times per day. That shine on the leaves is caused by canna cure, which is pest controll. Always spray them before lights go off.
But that's good note and thanks for that. I will avoid any spraying of the leaves in future, when lights are still burning.

Creeperpark said:

Too much fertilizer! You are burning them! You only need about 350 ppm or 0.7 EC. anything over could cause problems.

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I'm not sure man. 0.7 EC is pretty low. I dont even start on this number. I used to start at 1.0 EC on fresh clones. Then 1.2 - 1.4 EC in growth. When switch to flowering i used to go from 1.6 to 2.0 or 2.2 max. Always get good results. But I dont want to devalue your answer. I will let my mind to think about that. Thank for your point of view bro. I appreciate it.

Sorry for my english guys. Hope it's ok.

rkcz said:

Great tip. Maybe you're right. But the problem does occure even after first week of growth or so after being transplanted into a pots. There is a true, that I've flushed them little bit more often in a past. Last few rounds I flushed them only when changing nutrients from grow to bloom, then after pk13/14 week (which canna recommend add only for one week) and then 10 days before harvest. But still irrigating to get some run off - around 20%. Apparently, this run off should prevent the formation of salt. But this is great tip. I'll start to flush them for more often. Thanks for that.

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Yea, Canna recommends 10-20% run off every time "and/or" flushing with plain water every one or two weeks. I don't hydro grow these days myself but back in the day it was recommended to flush with pH adjusted water because hydro nutes are mineral based nutrients and salts would build up in time. So start flushing them with plain water at least once in two weeks, starting right away, and i'm sure you will get good results like you used to.

About coco..
Some coco brands have alot of salts in them straight out of the bag and it has been recommended to flush the coco with pH adjusted water before planting anything in it. So if you start seeing salt build up symptoms already after a week, it may be the coco already had too much salts in it to begin with.



Also.. Like someone mentioned about over feeding..

The leaves on your plants look abit dark, and thou you may not see too much nute burn from over feeding you can still be over feeding them. = If you look at cannabis plants growing in the wild, they don't look nearly as dark green as you see most plants grown indoors. Pushing them with heavy feeding wont give you better yields, not much anyways.. Overly dark green plants also produce harsh smokes, so you will get better smoking product by feeding them less.

it's been so long since i've hydro grown myself, but to me EC 2.0-2.2 seems quite alot.
Mandala Seeds recommend around EC 1.2 for their landrace hybrids and their Satori strain grew just fine with around EC 1.2 when i grew them in coco about 10 years ago.

..i grow with BioBizz nutes in regular supermarket potting soil and for "low/medium feeders" like Haze hybrids, C99, Blueberry, NL, Exodus Cheese, Herijuana, Black Domina, landraces etc. i give them around 40%-50% of what BioBizz recommends in their feeding schedule. So, maybe try feeding them around 1.2 -1.6 range and see how they grow.


Here's what Mandala Seeds write on their web site:

[FONT=&quot]Hydroponics and EC[/FONT]
[FONT=&quot]With a low to medium range strength (i.e. EC 1.0-1.6 mS/cm) you should be in the safe zone and can then optimize this if necessary. This recommendation is based on a starting EC of 0.4-0.5 mS/cm of your water. Adjust accordingly if your water has a very different EC and consider purifying your water if the EC is high. During flowering most Mandala strains can be grown with approx. [/FONT][FONT=&quot]EC 1.0-1.2 mS/cm and don't require heroic dosages. [/FONT]
[FONT=&quot]https://www.mandalaseeds.com/Guides/Fertilizing-Smart-Guide#Hydro [/FONT]

I hope you'll get it sorted and i'm sure you will. Flush with water more often and feed them abit less, i'd say. Peace.

Creeperpark said:

Too much fertilizer! You are burning them! You only need about 350 ppm or 0.7 EC. anything over could cause problems.

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This is my vote. I can't count how often I've done this. They always look like this if I overfeed. I always feed until I see burned tips, then back off the feed a bit. Sometimes I have to flush to get back to healthy. I have to say that under watering will also do this.

I have one strain that will eat whatever you throw at it. Especially in the ground. Others, not so much.

a couple of points.
If it was the light burning the plants, then it would be the leaves that are closest to the light that are most affected - from the pics this does not look to be the case.


To me it looks like some kind of nutrient burn or lockout/deficiency. It almost looks like it is something that happened a while ago and the plants are now recovering from... perhaps you made a mistake mixing or something bad happened on one occasion ? the leaves were wet under the lights one time a while ago when they were smaller?



there looks to be some healthy new growth there, i would keep going... the dead fans are unsightly but it is early in flower and the plants may well shake it off and crop ok for you.


remember, the old dead leaves will not recover. Look at the new growth and if it is healthy then perhaps the problem is behind you ?



VG

VerdantGreen said:

a couple of points.
If it was the light burning the plants, then it would be the leaves that are closest to the light that are most affected - from the pics this does not look to be the case.


To me it looks like some kind of nutrient burn or lockout/deficiency. It almost looks like it is something that happened a while ago and the plants are now recovering from... perhaps you made a mistake mixing or something bad happened on one occasion ? the leaves were wet under the lights one time a while ago when they were smaller?



there looks to be some healthy new growth there, i would keep going... the dead fans are unsightly but it is early in flower and the plants may well shake it off and crop ok for you.


remember, the old dead leaves will not recover. Look at the new growth and if it is healthy then perhaps the problem is behind you ?



VG

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Hi bro. Thank you for the advice. Is it true, that I spray them with pure RO water when I get them as little babies. Because they dont have such a big root system, thats why I spray them into the leaves and unfortunately yes, during the light cycle. The lights are about meter above them that time and start very soft on them with 250W MH to not stress them with such a too much light. But I stop to doing this after a week or so. As time go on, I switch to 400W MH and get the bulb little down - about 50 cm, but there is no spraying with RO water on to leaves yet. In the flowering cycle, I use 600W HPS bulb.


It is true that new growths look healthy. However, the problem always affected older leaves, which became worse and worse over time, and in the meantime it also attacked newer growths. I'll see what time brings. I will take the advice of a colleague and I started regularly flushing the growing medium every two weeks. I also diluted the nutrient solution to 1.5 EC. I measured wastewater and it had 2.2 EC. The nutrient solution had, at that time, 1.8 EC. So they longed for water and left the fertilizer.

I will continue also with the preventive spraying of CANNA cure until some solid buds starts to form.

I took a few closer pictures of one of the infected leaves. Unfortunately, my camera can't get closer. I want to note that I already checked the leaves with a magnifying glass and saw nothing. I bought a pocket microscope, but I'm having a hard time with it. Probably I get some sh*tty one.

rkcz said:

I will take the advice of a colleague and I started regularly flushing the growing medium every two weeks. I also diluted the nutrient solution to 1.5 EC. I measured wastewater and it had 2.2 EC. The nutrient solution had, at that time, 1.8 EC. So they longed for water and left the fertilizer.

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Runoff with higher readings than input is bad. You're accumulating whatever the plant isn't using (over-fertilization), so the plant is slowly poisoned.

It also looks like PH is involved, can you report on the PH on your nutrient solution going in and as runoff? Most times acidity drops with over-fertilization...

yeah, that does look like nutrient or salt burn to me. The fact that one strain was much more badly affected than another would also point to that - they were more nute sensitive i guess...

Switch to a coco specific nutrient. Check your runoff and never let it get more than 300ppm above your feed. I feed 320ppm and my runoff is around 420ppm never had a problem