Crazy issue I don't have an answer to

[RandomGrower]

OK, so here it goes. I am a long time commercial grower for over 20 years. Ive been growing for over 25 years though... first couple weren't terribly successful. I havent been on a forum for probably 15 years.. been too busy and had kids and life happened etc. As much as it pains me to be on here I have an issue I cant seem to solve and generally speaking I dont know anyone who knows more than myself and the other proffessional growers around me... with that being said noone seems to be able to figure out my current problem and we have over 100 years of indoor marijuana growing under our belts combined. I can honestly say I never in a million years would have thought I would be reaching out to strangers to help but if there is one thing I have learned over the years is pride and arrogance have no place in the growroom, so here I am.

Long story short we have a new facility that just came online with a couple hundred bloom lights in it... this is probably my 20th such grow Ive managed and I have never had an issue I didnt have the answer to. I can humbly say I have no answer for this current problem.. Ive tried everything I can think of and hence Im here hoping someone with a different perspective might have an idea I havent thought of.

Essentially the issue is the plants will veg just fine but once they go into flower they will burn up in 1-3 weeks from what looks like light burn but I dont see how thats possible as the par is well below average... even with the Gavita LED 730E turned all the way down they will eventually all burn up. Here are the basic facts

Strains: lots of them, from Cake to Silver Haze to Lemon OG and everything in between
Substrate: HP Mix #4 mixed with Perlite. Roughly 30% pure perlite mixed with 70% HP Promix #4 (Ive successfully run this mix in commercial grows for over a decade)
Nutes: GH 3 part (yes I know, please spare me the lectures... again, been using it for over 15 years and currently use at other facilities with no issues other than its GH and generally sucks.. this choice isnt mine) Cal Mag once a week (although we have tried with every watering, and not using it all... all ended with the same reult
PH: adjusted to 6.. have tried RO water and tap water.. same results (buffering RO is a pain though as many know already)
Lights: Gavita 1700E LEDs. This is newer for me but again we are using them at other grows with no issues other than having to run the rooms a bit warmer to keep the VPD and leaf temp up.
Full enviro control: 10 tons of AC per 20 lights, Quest Dehuies AND humidifiers in every room to keep the VPD perfect, CO2 injection via a central Cryo tank.
Enviro specs: will fluctuate a bit but generally speaking were running 80degrees, 65% humidity, 1200ppm CO2.
Pests: Nothing other than the occasional Thrip here and there but they are controlled pretty well with Neem and pyrithrin bombs.. I should have them eradicated in another couple weeks until they crawl out of a new bag of Promix then I will eradicate them again if the preventative spraying lets any slip through. Of course I spray with lights off and wont turn them back on until the next day.
Nutes: running half strength currently to postpone the burn .. watering with about 800ppm.. runoff is generally good at first (under 1500 and PH6) and then as time goes by it will rise because the plants arent uptaking anything.

Please see the pictures. Some strains will burn up faster than others but eventually, they will all cook. 1 out of 10 rooms will make it.. most dont.. there is no difference I can tell from one room to the others. We are using this exact setup at other large commercial grows with zero issues.

Any ideas would be greatly appreciated.. you can generally assume anything basic I have probably already tried but hell, Ive even tried very expensive complicated things to fix this to no avail. It does not seem like a viroid or fungal infection.. Ive dealt with both many times over the years... but maybe this is a new one noone has ever seen? who knows

PS: I know the lights in the pics are Hortilux lights.. just a couple rooms are running those.. the rest are gavitas.. specs are essentially the same and the rooms do the same thing regardless of the lights it would seem.. Ive also tried Gavita 1000w DE's and the exact same thing happened. Its a real mystery. They just seem to essentially stop growing and burn like this once they get into flower... I cant make any sense of it. Everything from substrate to nutes to lights we have used successfully and still do at other grows.. like literally the same pallets of substrates and nutes etc.

One small caveat ... Initially in this building we bought some equipment from another grower.. it took us about 4 months to realize the hoses were leaching Bifethrin and Thiabendizole into the plants... but at very small quantities.. like 50 ppb (not ppm) when the soil was tested. We have since replaced all the hoses and pumps and reservoirs and this hasnt seem to fix anything... although there is a chance they may have seen small amounts of it when they were in dixie cups but again they all veg just fine.. this only happens 1-3 weeks into flower and it should be way way way diluted by then.. additionally the previous grower has said he didnt have any issues ... noone seems to really know where the thiabendazole came from though.. Im guessing it was in some kind of multifaceted fungicide the last grower was using to conteract bud rot or PM... we dont have either.

Any wild ideas or even basic ideas are welcome. We are really starting to feel like were in the twilight zone or something... maybe this building was put on an indian burial ground.. who knows. Ive also checked cameras to see if maybe a digruntled employee is sabotoging things and havent seen anything suspicious plus, we are all happy so that really wouldnt make sense although I suppose it isnt impossible. But even if that was happening what would cause light burn at like 425 PAR at the canopy top? We are way under the amount of light and nute strength we would typically run at but all that does is postpone the inevitable it seems.

In these pictures you will see the necrosis on the leaves.. unlike with nute burn the dead sides dont go from green to crispy.. they are almost soft when they first die.. even velvety.. and then after a day or two will turn crunchy. So So weird.

Thank you to all who read this, Noob to expert. This is completely unlike anything I have ever experienced before.

 

[Imzzaudae]

In future grows. Ether use at least 25% Vermiculite or find a good quality silica amendment. Vermiculite contains Silica.

Silica is great for bud production and is also a real hard core defense against mold and Mildew.

I promise you that your problem is an over dose of Potassium. You need to be mindful that your plants only need 60 ppm Phosphorus.
100 or so ppm potassium is right on the button.
100 to 150 ppm Calcium and Magnesium is plenty.

When you calculate your (N) for flower, use only enough bloom booster like 0-50-30 to keep your solution at 60 ppm
Phosphorus. 100 or so ppm potassium. 100 to 150 ppm Calcium and Magnesium.
Your burning them with P-K. Calculate your current P-K ppm's and see where your at.
I'd say the way your tips are rolling up maybe a little hot lights.
Hope this helps you.

 

[GNick55]

improper environment, incorrect feeding, and pest stress..
and why using ph stuff with promix hp?.. than why using synthetic nutrients with promix hp?
too many things here don’t make sense as in having experience especially a 100 yrs combined but this???
goodluck

 

[BryanOconner]

Fellow commercial grower. Retired here. Do you have a lumen meter ? i see BURNT TO A CRISP leaves .
Amazon 25 bucks .
Lux same as lumens as in numbers .
https://www.growbarato.net/blog/en/how-many-lumens-do-cannabis-indoor-plants-need/
And if you want advice how to run a commercial set up ask. Shoes jeans in a grow room equal failed grower . I would fire an employee and dock his entire check and small claims court for wearing that in my room. Best of luck lol.

 

[RandomGrower]

In future grows. Ether use at least 25% Vermiculite or find a good quality silica amendment. Vermiculite contains Silica.

Silica is great for bud production and is also a real hard core defense against mold and Mildew.

I promise you that your problem is an over dose of Potassium. You need to be mindful that your plants only need 60 ppm Phosphorus.
100 or so ppm potassium is right on the button.
100 to 150 ppm Calcium and Magnesium is plenty.

When you calculate your (N) for flower, use only enough bloom booster like 0-50-30 to keep your solution at 60 ppm
Phosphorus. 100 or so ppm potassium. 100 to 150 ppm Calcium and Magnesium.
Your burning them with P-K. Calculate your current P-K ppm's and see where your at.
I'd say the way your tips are rolling up maybe a little hot lights.
Hope this helps you.

Thanks for the thought but we are running very low nutes.. and we are running the same nutes elsewhere at triple the strength, same rooms, same everything, no burn. Nutes are below 700ppm… been using these same nutes for 15 years with no issues. Lights are dimmed to 50% tops of plants are seeing less than 450PAR.

 

[RandomGrower]

Fellow commercial grower. Retired here. Do you have a lumen meter ? i see BURNT TO A CRISP leaves .
Amazon 25 bucks .
Lux same as lumens as in numbers .
https://www.growbarato.net/blog/en/how-many-lumens-do-cannabis-indoor-plants-need/
And if you want advice how to run a commercial set up ask. Shoes jeans in a grow room equal failed grower . I would fire an employee and dock his entire check and small claims court for wearing that in my room. Best of luck lol.

If you read the post I state that we have already checked the light.. its well below even the average. Denim never hurt plants but thanks for the opinion.

 

[RandomGrower]

improper environment, incorrect feeding, and pest stress..
and why using ph stuff with promix hp?.. than why using synthetic nutrients with promix hp?
too many things here don’t make sense as in having experience especially a 100 yrs combined but this???
goodluck

VPD is perfect, feeding is low but thats because when we feed it normal amounts they burn even faster. There are really no pests to speak of.. just the occasional thrip. We use Promix because we own a hydro store and buy it by the truckload.. not for the mychorizae or anything. Again, been running this setup for over a decade with zero issues.. well over 100k sq ft of grows overall.. no issues in any building besides this new one.

I understand that the two most arrogant people in the world are likely rap stars and marijuana growers.. i know.. i used to be there myself. Im just here for any ideas I havent thought of. Appreciate the feedback.

 

[N1ghtL1ght]

700ppm is much too low, to me it looks like a deficiency. Ok you turned down the light (when you wrote "450 PAR" does this mean PPFD?)
A long time ago I've seen something similar but the guy who did that, well, we've never been able to pinpoint what was the real cause as he led a helicopter grow, ie. applying changes way too fast and often.

It looks as if something is preventing correct water management in the sites where transpiration should happen most strong. I doubt the irradiance alone would be solo responsible for this given how much light Cannabis can handle. Plus your running CO2. But if these parts are already, or gradually become, dysfunctional, then maybe that is still adding to the problem.

Do you maybe have photos, best in normal daylight, when the problem first begins to manifest? The very first day you see something at the leaf?

The Si supp is a good idea, it helps the plant translocate internally nutrients around, and on its own, has a large tolerance of being overdone. Not saying it would solve the problem but maybe help to alleviate it.

 

[N1ghtL1ght]

Btw what is your avg. leaf surface temp?

 

[N1ghtL1ght]

Do you have a tap water analysis? What's your pH downer, and how did you treat your RO?

 

[RandomGrower]

Thank you for the questions. Nice to see someone that doesnt feel the need to flex on a complete stranger on an anonymous forum. I kind of figured I would get a couple haters but thought that those people had largely grown up. Apparently not.

In any case to your question. Yes, we have done a tap water analysis. There were certainly things that were surprising like chloroform and lead but honestly nothing out of the ordinary compared to other grows we have in the same area. Initially the water was one of the first things we thought of because the water was coming out super high in dissolved solids… like 320ppm high. So we installed a very large RO system.. that of course cane with its own issues because once you remove all the calcium it makes it hard to PH balance and eats all the minerals out of your probes so they dont last very long. Long story short the tap water ended up coming back down to about 90ppm after 60 days or so but we kept using the RO since we had already spent a bunch of time and money putting it in. This last month we ran one room with one side on tap water and the other on RO water, the results were the same.

Honestly Im fairly confident we are experiencing light burn but I dont know how that could be possible given that there is very low light in the rooms. Typically we will run bloom rooms around 1000-1500 PAR but these rooms will get what looks like light burn at a meager 400 par… which is less than they were even vegging under.. but we have zero problems in veg. Its almost like something is opening up the stomata to accept more light than it should or something. Its just all around confusing. To make matters more confusing we have 8 rooms side by side by side. The last room in the row will flower plants just fine these last two rounds.. all the way through completion, no issues, lights at 100%. This last time room 1 was successfull too but did see a little bit of burn. But ALL the other rooms in the middle just cook. All have the same lights, water, nutes, temp, humidity etc.

One difference between this facility and our other ones is these rooms we had built with trench drains. Supposedly the plumber put in pea traps though so no gas should be able to come up through them but that was one thing I was concidering… methane poisoning, particularly because room 8 is the furthest from the main sewer line.. but then room one, the closest succeeded. And there is also no smell emanating from the drains and in the past when I have had pea traps dry up and let gas in you can smell it.. no smell here.

Uuuuggghhhh. I just really dont know. In 20 years of doing this professionally this is the first time im truly stumped. Ive had issues of course, ive made bad decisions of course, especially early on, but the last 10-15 years has been pretty smooth sailing. Its just wild to me that this is happening and I dont know whats causing it.

Sorry for the long reply.

 

[RandomGrower]

Btw what is your avg. leaf surface temp?

Leaf surface temp is staying right around 80 with the rooms around 82. These LEDs require a bit more heat in the rooms than the HIDs but our VPD is pretty much on point. With that being said I have also run rooms at 72 with no issues, just slower growth. We have tried cooler rooms and warmer rooms in this building with no real difference except the colder room grew slower and thus showed the burning slower.

 

[RandomGrower]

Leaf surface temp is staying right around 80 with the rooms around 82. These LEDs require a bit more heat in the rooms than the HIDs but our VPD is pretty much on point. With that being said I have also run rooms at 72 with no issues, just slower growth. We have tried cooler rooms and warmer rooms in this building with no real difference except the colder room grew slower and thus showed the burning slower.

We also change the temp of the rooms generally.. warmer in veg and beginning of bloom then cooler later on with lower humidity.

 

[RandomGrower]

700ppm is much too low, to me it looks like a deficiency. Ok you turned down the light (when you wrote "450 PAR" does this mean PPFD?)
A long time ago I've seen something similar but the guy who did that, well, we've never been able to pinpoint what was the real cause as he led a helicopter grow, ie. applying changes way too fast and often.

It looks as if something is preventing correct water management in the sites where transpiration should happen most strong. I doubt the irradiance alone would be solo responsible for this given how much light Cannabis can handle. Plus your running CO2. But if these parts are already, or gradually become, dysfunctional, then maybe that is still adding to the problem.

Do you maybe have photos, best in normal daylight, when the problem first begins to manifest? The very first day you see something at the leaf?

The Si supp is a good idea, it helps the plant translocate internally nutrients around, and on its own, has a large tolerance of being overdone. Not saying it would solve the problem but maybe help to alleviate it.

Tell ya man.. you seem to be the most helpfull on here. I will give the silica a try. I have kind of steered away from it over the years because it reaks havok on the PH in the rezs but hell, at this point im open to try anything.

 

[RandomGrower]

700ppm is much too low, to me it looks like a deficiency. Ok you turned down the light (when you wrote "450 PAR" does this mean PPFD?)
A long time ago I've seen something similar but the guy who did that, well, we've never been able to pinpoint what was the real cause as he led a helicopter grow, ie. applying changes way too fast and often.

It looks as if something is preventing correct water management in the sites where transpiration should happen most strong. I doubt the irradiance alone would be solo responsible for this given how much light Cannabis can handle. Plus your running CO2. But if these parts are already, or gradually become, dysfunctional, then maybe that is still adding to the problem.

Do you maybe have photos, best in normal daylight, when the problem first begins to manifest? The very first day you see something at the leaf?

The Si supp is a good idea, it helps the plant translocate internally nutrients around, and on its own, has a large tolerance of being overdone. Not saying it would solve the problem but maybe help to alleviate it.

And yes, PPFD.. i was just stating the reading on the PAR meter.

 

[imgrowing]

probably a dumb idea but is there any chance of a bad batch of pro mix?
have any customers had any complaints?

 

[RandomGrower]

Do you have a tap water analysis? What's your pH downer, and how did you treat your RO?

We dont use down. If anything its up.

probably a dumb idea but is there any chance of a bad batch of pro mix?
have any customers had any complaints?

There are no dumb ideas here man. I suppose yes that would be possible but our grow disperses the promix to all the other grows. All off the same truck, same pallets and the other grows are having no issues:/

 

[Lifted1]

Have you had your plants tested for Hop Latent Viroid?

the symptoms you describe sure sound like it.

If i were in this circumstance i would isolate a room and give it the deepest cleaning / sterilization you have ever perfomed. Starting with the reservoirs, drip system, and trays, etc. Bleach the hell out of them. Get all new scissors or sterilize them as well. Get a new test strain to run only in that room. The problem with getting the new strain is that you and your team are now the source of the problem. Its super easy to transfer the virus. How will you manage to work with mulitple rooms/strains and not cross contaminate the newly clean room/plants throughout the days????

imho.......If you have the virus you will need to ditch all your gear and start from new. talking from experience here..... its a huuuuuge setback but biting the bullet and moving on is the only real solution and if this is your problem the sooner you do it the better.

I also went through this and was bewildered for months before i finally figured it out. I was working harder than ever to pull averages that still paled in comparison to all the years of previous successful runs. and then it dawned on me. I had taken in some cuttings and although bug free(always quarantine and verify) my runs had been getting worse and worse. The first runs with the new cuts were pretty good and i was excited dial them in but gradually the runs with the newest started yellowing around 2nd week of flower and then just got worse. Then all my strains started exhibiting the same failing characteristics as the newest strains. and then the lightbulb went off. its got to be some kind of virus. Once i realized this i researched it and learned of this dreaded virus. all my beautiful decade plus collection had to be tossed away.

Your plants will always look good in veg with this virus and even if you nurse a crop through the harvest will never reach its potential.

If your not up for the task of starting over on a hunch, send out a leaf for lab testing asap. if you've got it, you better get started on the starting over process and think about how all the plants and employees interact because everything is a potential contaminant at this point.

best of luck

 

[GNick55]

Have you had your plants tested for Hop Latent Viroid?

the symptoms you describe sure sound like it.

If i were in this circumstance i would isolate a room and give it the deepest cleaning / sterilization you have ever perfomed. Starting with the reservoirs, drip system, and trays, etc. Bleach the hell out of them. Get all new scissors or sterilize them as well. Get a new test strain to run only in that room. The problem with getting the new strain is that you and your team are now the source of the problem. Its super easy to transfer the virus. How will you manage to work with mulitple rooms/strains and not cross contaminate the newly clean room/plants throughout the days????

imho.......If you have the virus you will need to ditch all your gear and start from new. talking from experience here..... its a huuuuuge setback but biting the bullet and moving on is the only real solution and if this is your problem the sooner you do it the better.

I also went through this and was bewildered for months before i finally figured it out. I was working harder than ever to pull averages that still paled in comparison to all the years of previous successful runs. and then it dawned on me. I had taken in some cuttings and although bug free(always quarantine and verify) my runs had been getting worse and worse. The first runs with the new cuts were pretty good and i was excited dial them in but gradually the runs with the newest started yellowing around 2nd week of flower and then just got worse. Then all my strains started exhibiting the same failing characteristics as the newest strains. and then the lightbulb went off. its got to be some kind of virus. Once i realized this i researched it and learned of this dreaded virus. all my beautiful decade plus collection had to be tossed away.

Your plants will always look good in veg with this virus and even if you nurse a crop through the harvest will never reach its potential.

If your not up for the task of starting over on a hunch, send out a leaf for lab testing asap. if you've got it, you better get started on the starting over process and think about how all the plants and employees interact because everything is a potential contaminant at this point.

best of luck

i was thinking this also but i don’t think it is,. maybe though..
even though he seems to have done good with them it’s kinda counterproductive the method he’s using..
anyhoo hope he gets the help he needs,..

 

[OklahomaTerpLordz]

What state are you in?

I'll tell you the fix. Monsanto has infiltrated your crop with engineered nanobots set on boof mode, and have the antidote price set at 1 million! Just kidding we don't need to worry about that until federal legalization.

Your issue is P bound in the promix. Could confirm with tissue analysis, medium analysis (M3 type compared to saturated paste). I can tell you effectively have less than 5ppm P available in solution.

How are you phing. Never grown with bottles but Gh pH is phosphoric, which is binding to excess Ca and waiting for microbes or exudates to release. Today's plants were not bred for slow P uptake. And the all-in-one Leds don't signal P uptake if it's missing the right spectrum of red. You're in a peat medium but not paying attention to phosphorus solublizers. Citric acid is the fix. Unless it drops pH too low. The fertilizer game is constantly changing shape. "Low P" is being pushed by companies contracted with foreign P mines who can't get good rates anymore. Responsible companies have bought up all the waste water contracts for P recovery. Struvite will be a common P input moving forward in Cannabis as it is easily released by organic acids and the ammonia offsets that acidity.

If you put a bunch of acids in your soil beforehand and buffer to that, the plant will fill with citrate, etc. I put every acid known to man in my soil before adding silicates/carbonates. That's why the hippies are so jazzed with microbes and ferments and cooking soils for months. It's all about the P cycle and having excess carboxylic acids so the plant doesn't dump all its resources into exudates (which it won't even do without proper light spectrum) . You see this exact problem all over the web always early bloom under Pimple stripe (what we call white led with red specs here and there) with P demand rising.

I asked what state you were in because there is no logic why things get out of whack other than microbial demographics. I used to grow mushrooms. Standard practice was to use isopropyl. Long story short anyone using isopropyl is working against themselves as the first microbes to return and flourish are the nastiest most hell bent desperate motherfuckers that don't play along with anything else. Same type of rules apply in soil. Pro mix is like an open petri dish. Some brands of nutes will make your soil smell like shit and what do you know, issues in those rooms.

Sorry to say you will never catch up to a -P issue in Cannabis. Top Cannabis growers use ungodly amounts of P in veg and foliar zinc boron magnesium (that's the only negative to high P in medium). Lots of people will tell you that Cannabis needs low P, but those people got red noses. I literally here the gurus talk about "luxury P" like it's a bad thing. Cannabis literally needs to load its leaves with P or you'll end up with a horrible product feeding enough soluble P throughout bloom. #1reason people say organic is better. The leaves have enough P in the right forms when things are working smoothly and it pulls all the sugars out of the leaves and into the buds. All the organic hippy bud that sucks, sucks because of -P and there's alot more of it than the organic community will admit. Because they don't know shit about nutes and Negatively influence the community with their vain hippy prayers and empty meditative ways.