Powdery Mildew - Large scale Greenhouse

[Cannama]

Hi Everyone,

I am new to ICMag but am happy to finally be here!

I work at a 300,000 square foot greenhouse in southern Ontario Canada. It is poly. 150 feet long by 100 feet wide and 30 feet tall.

I am an internal consultant on the greenhouse and am not apart of the grow team. I have been indoor growing for about 6 years now and had great success. I was hoping to get some feedback/advice.

We have been struggling to control Powdery Mildew and am looking for some advice. In terms of air exchange, it is limited. The greenhouse sits around 23 degrees Celsius and humidity is pretty high. All of this is bad for PM lol

Does anyone have any suggestions to help control and reduce the around of PM we are experiencing? We are limited on fungicidal control methods due to regulations.

 

[GatorGumbo]

Solving the conditions that caused it to manifest would probably be your best bet. I'm not trying to be cute when I say that, it's just that with limited control methods at your disposal it's likely to happen again unless you can trend the environment away from inviting it. If you could manage that, perhaps the approved options would be more viable.

 

[Pepé The Grower]

What he said^^

If you can neither solve your air circulation issues or use anti-PM chemicals, you're fucked unless you switch to PM resisting strains.

 

[redlaser]

To control powdery mildew the environment needs controlling, can’t have the big temp and humidity swings.

UC Davis has a nice risk indication model that assesses points for certain conditions, x number of days at a certain temp and humidity will initiate outbreaks generally speaking.
It’s mostly about grape production but would apply to other plants.


www.ipm.ucanr.edu/PMG/r302100311.html

 

[slownickel]

Hi Everyone,

I am new to ICMag but am happy to finally be here!

I work at a 300,000 square foot greenhouse in southern Ontario Canada. It is poly. 150 feet long by 100 feet wide and 30 feet tall.

I am an internal consultant on the greenhouse and am not apart of the grow team. I have been indoor growing for about 6 years now and had great success. I was hoping to get some feedback/advice.

We have been struggling to control Powdery Mildew and am looking for some advice. In terms of air exchange, it is limited. The greenhouse sits around 23 degrees Celsius and humidity is pretty high. All of this is bad for PM lol

Does anyone have any suggestions to help control and reduce the around of PM we are experiencing? We are limited on fungicidal control methods due to regulations.

What are the highs and lows of humidity and temperature over 24 hours? The temperature is good.

 

[Cannama]

Temperature ranges are about 18 at lowest and 26 at highest.
RH can swing drastically from 45-75%.

I am recommending that we invest in good climate control but that can take awhile...lol
We do have a super lemon haze pheno which is really resistant. But resistance can only go so far no?

Thanks everyone for your replies

 

[Pepé The Grower]

Depends what you mean by really resistant. In my experience some strains or some phenos of a specific strain are litteraly immune to PM,no matter what( but they may be suceptible to others kinds of mold).

 

[Cannama]

It is beside a pheno of master kush which is absolutely caked lol and it has 2 spots on the whole plant

 

[dank.frank]

300,000 sq ft grow consultant, has to come ask a bunch of hobby growers how to run their operation... (which is really 15,000 sq ft because cubic measurements are a different thing)

Perhaps if they hired experts in the first place, instead of trying to penny pinch and hire a basic labor force there wouldn't be powdery mildew issues.

Sorry. I have no pity on those who are in the game for purely capitalist objectives. You want answers? You should perhaps, HIRE A RISK MANAGEMENT CONSULTANT -oh wait, that's supposed to be you.

Seems to me this post is more about you saving face and your job.



dank.Frank

 

[Lastdon]

Hi Everyone,

I am new to ICMag but am happy to finally be here!

I work at a 300,000 square foot greenhouse in southern Ontario Canada. It is poly. 150 feet long by 100 feet wide and 30 feet tall.

I am an internal consultant on the greenhouse and am not apart of the grow team. I have been indoor growing for about 6 years now and had great success. I was hoping to get some feedback/advice.

We have been struggling to control Powdery Mildew and am looking for some advice. In terms of air exchange, it is limited. The greenhouse sits around 23 degrees Celsius and humidity is pretty high. All of this is bad for PM lol

Does anyone have any suggestions to help control and reduce the around of PM we are experiencing? We are limited on fungicidal control methods due to regulations.

BURN THE GOD DAMN PLACE DOWN.

How come they hired you and you cannot handle the problem.

Thats what these LAME LPS GET.

Lightgreen2k from IG.

Lightgreen2k on rollitup too

 

[Lastdon]

It is beside a pheno of master kush which is absolutely caked lol and it has 2 spots on the whole plant

Which LP are you.. not tweed, you are one of the smaller ones.

Why dont you know this information

@theloudreserve and I where just talking about all the bullshit strains at the lps.

Tell your boss he can get some real growers at 100k
Or lose 1 million upwards.

You will be wiped out totally in two harvest. They thought weed was like growing corn

Fuck it man.
Powdery Mildew is the next worse thing to Russet Mites.

 

[Limeygreen]

Lots of knowledge in Leamington on greenhouse climate control. It's not so much about air exchange that causes mildew. The swings in your humidity are the biggest problem, exhaust fans only offer so much, vents help more in conjunction with heat to keep a more stable humidity level. Indoor versus greenhouse are vastly different in the mindset of growers I have talked to, indoor is a complete joke if you try to do it in a greenhouse.

Circulation fans are needed HAF to maintain a more even temperature and humidity profile. If you have vents you shut off your haf fans when open roughly 15% to save electricity as the air doesn't get circulated enough. Try putting out different thermometers or hobo sensors etc to see different spots in the greenhouse and different heights as well. This will help you asses your temperature profile and humidity profiles. Drafts can cause mildew to go like wildfire, dewpoint does as well. I have a strong suspicion that you have a very uneven climate in your 'greenhouse'.

There are crop advisors out there that help businesses out but if you don't know how to run a commercial greenhouse you can't just pick it up over night.

 

[nothernblue]

posts like this blow my mind. I know I'm not being helpful but damn.

 

[gotnoname]

suprised you have high RH during winter its usually pretty dry..
increase temps at night, have air circulation HAF, spraying water during daytime can wash some mildew off, burn sulfur if youre allowed.

You could also get dehumidifiers, all those purpose built ones are pretty expensive, but you could convert old watercooled 5tons ac into dehumidifiers for cheap if you have them...

did you guys get budrot last summer ? heard nothing but bad things from greenhouse growers in ontario in the last years.

 

[gotnoname]

i currently run a 10k sqft glass greenhouse in canada and I can tell you greenhouses are a nightmare for indoors growers.

during winter;
-heating is expensive
-light is very low
-sunlight dosent get to the plants (sun is too low or too much obstacle)
-equipments are more expensive and complex

during summer (light dep or full season)
-you get bud rot !!! (or invest a lot of money for dehumidifier)
-Eastern canada is humid
-difficult to lower temperature

on top of all these extra issue you still deal with what you would deal with indoors.
I thought greenhouse would run cheaper but end up be more expensive and the final product isnt that nice compared to indoor, since you cant really control your environement proprely.. pretty pointless IMO

 

[gotnoname]

only way to run a greenhouse in winter would be to have a light plan similar to indoors (7x7 to 6x6 per 1000w) and close the climate curtain on dark/cold days. 10x10 per light is pretty low even for veg, considering how shitty canadian winters are.

 

[Cannama]

LOL I have already told them what we need to do. When time and money will take awhile I opened up to the community to see if anyone had any other options in the mean time. No need to be a keyboard warrior.
And not its actually 300,000 square feet of grow space hahah but thanks anyways.

Im sure you have dealt with PM on a massive scale like that before right? I didn't cause it, was just brought in 2 days ago. lol

 

[Cannama]

only way to run a greenhouse in winter would be to have a light plan similar to indoors (7x7 to 6x6 per 1000w) and close the climate curtain on dark/cold days. 10x10 per light is pretty low even for veg, considering how shitty canadian winters are.

Yeah we are getting some better lights in finally next week, they are currently using LEDs too far above canopy and getting real weak PAR readings.
But there was long term plans to go to Gavitas!

 

[Cannama]

Thanks for the useful feedback.
Yeah the greenhouse design is majorly flawed, just takes time to fix things as crops need to be fully finished and takes construction time.
This one range that I am working in, is a shitting card to be dealt. They were strawberry growers now trying to grow cannabis...nuff said.

But I am working with them to get some better humidity control first and getting their pruning/training practices down. They are doing sea of green method on mass scale and you can feel the lack of airflow, its stagnant.

Many things in the works, just takes time in this industry!

 

[soil margin]

You fucking amateurs.

Skim milk. Dilute it maybe 5 to 1 or something and spray it all over the leaves. Works better if you spray multiple times.