# Crown Rot Prevention in Large Greenhouses



## JAB (Aug 7, 2016)

So I was wondering how big nurseries / greenhouses that spray from over head either via hand sprayer or automatic, how do they prevent crown rot and water from accumulating in the nooks and crannies? 

Was just thinking of this the other day.


----------



## gonewild (Aug 7, 2016)

They don't prevent it but because the surrounding environment is correct the excess water does not induce rot.

Aside from that using flexible cultural practices when applying water reduces potential problems. Like water early in the day and not at all when conditions wont allow evaporation to dry up the greenhouse.


----------



## Linus_Cello (Aug 7, 2016)

Also lots of air movement from fans


----------



## Happypaphy7 (Aug 7, 2016)

Rots still happen, including all kinds of other diseases as well.
Plants in greenhouses are not immune, and I won't say they are better off or worse off. 
If anything, with so many plants crowded up, it serves for a great conditions for disease and pests to thrive.

Depending on the nursery, they practice preventative measure like spraying at particular season, usually hot and humid summer during which rots and other diseases are common. 
This does not eliminate rot, though. It's just impossible to avoid. 
The goal is to reduce the occurrence to the minimum possible to avoid financial disaster. 

Other smaller scale nurseries may just pull out the bad plants and discard to prevent further spread.

Nurseries I've visited all had diseased plants. That's just how it is. Some had more and some had less. That was the only difference.


----------



## Ray (Aug 8, 2016)

Exactly...water very early, when weather allows, and make sure there's good air movement. Speaking as a "small nursery/greenhouse" operator, where overcrowding can be a rampant issue, I found that with regular treatment with the Inocucor product, rots virtually vanished (which is why I sell it...).


----------



## Dandrobium (Aug 8, 2016)

I have a rainbarrel where I apply 2-3 tablespoons of Physan before a big rainfall. This seems to minimize any rot/fungus I used to get. That would be a max dosage though, as additional rain would further dilute it during use.


----------



## Redtwist (Aug 8, 2016)

On a similar topic, as someone who always worries about getting any water in the crown (mainly because temperatures here in the UK cant always be relied upon to evaporate water quickly, and because growing my plants indoors air movement can also be limited) do people think it is actually beneficial to occasionally 'flush' the crown/leaf bases? Dust and debris does accumulate in there over time, which I expect can equally cause health problems for plants in the end.


----------



## gonewild (Aug 8, 2016)

I think it is a good idea.
But I usually flood the crowns when I water so they stay clear of debris.

On the other hand in nature they are packed with all kinds of crud.


----------



## Stone (Aug 9, 2016)

gonewild said:


> They don't prevent it but because the surrounding environment is correct the excess water does not induce rot.
> 
> Aside from that using flexible cultural practices when applying water reduces potential problems. Like water early in the day and not at all when conditions wont allow evaporation to dry up the greenhouse.



I agree with this. Water does not cause disease, it can only assist it. My orchids in the shade house outside never get attacked by pathogens. In summer - and sometimes even in winter -I water late in the day. 4 or 5 pm and they remain wet all night unless it's windy.
The big difference is air movement and I suspect not just air movement but air exchange is also involved. 

Unless you are rich, it is too expensive to move so much air and heat introduced air into a green house. 
That's why so many tons of leaf fungicides are sold every year.

I think perhaps the volume x the time period of water falling on the plants in the habitat may also play a part. 
When it rains in the habitat, the plants are showered for sometimes hours.
In other words they are constantly washed so what chance do pathogens have of building numbers?
Who here overhead waters their plants for 3 or 5 hours non stop and then follows that up with 12 hours of strong wind from gigantic fans connected to V8 engines?


----------



## gonewild (Aug 9, 2016)

Stone said:


> I agree with this. Water does not cause disease, it can only assist it. My orchids in the shade house outside never get attacked by pathogens. In summer - and sometimes even in winter -I water late in the day. 4 or 5 pm and they remain wet all night unless it's windy.
> The big difference is air movement and I suspect not just air movement but air exchange is also involved.
> 
> Unless you are rich, it is too expensive to move so much air and heat introduced air into a green house.
> ...



Exactly,
Mike until recently I thought the air movement (wind) was the major factor also. But now I think the other point you mentioned, Gas exchange, is more significant. For the last year and a half I have had a bunch of Phals growing under shade cloth. They get all the rain that falls here and that's a lot. Day or night and their crowns have never rotted. The reason I think it's not so much a factor of the air movement is because the shade house has walls and there is basically no wind or breeze. But they have an abundance of fresh air to exchange gases. So maybe crown rot and other bacterial diseases are aggravated by low levels of CO2 or high levels of some other gas.


----------



## Ray (Aug 9, 2016)

OK, but now let's consider the Andean species that stay constantly bathed in fog. No rain to wash them clean, just wet, wet, wet...


----------



## gonewild (Aug 9, 2016)

Ray said:


> OK, but now let's consider the Andean species that stay constantly bathed in fog. No rain to wash them clean, just wet, wet, wet...



In regards to keeping them flushed clean when they stay constantly wet (moist) in the Andes they have a constant living active population of organisms keeping them un-polluted. That's why your Inocour works.

They stay wet at night and they do not rot. But also most of the plants are not very pretty all covered in moss and lichen.


----------



## JAB (Aug 10, 2016)

Thanks guys! 
Do you think species such as Dracula are more resistant to rot?


----------



## gonewild (Aug 10, 2016)

JAB said:


> Thanks guys!
> Do you think species such as Dracula are more resistant to rot?



Than what?


----------



## orcoholic (Aug 10, 2016)

Don't most of the orchids in the wild grow with their leaves pointing outwards, not upwards, thus preventing any water accumulating in the crown? The excess water just runs out of the crown. I've never had a mounted orchid show any signs of crown rot.

My guess is that most large facilities have a regular program for pesticide/fungicide/bacteriacide application. It wouldn't make financial sense for them to do otherwise.


----------



## C. Rothschild (Aug 10, 2016)

Yes the place I go to said they use Consan 20 but they need a license to use it. I think that only applies if the plants are to be sold. Same thing with other chemicals if you read the fine print. No idea why.


----------



## Stone (Aug 10, 2016)

JAB said:


> Thanks guys!
> Do you think species such as Dracula are more resistant to rot?



Some plants are absolutely more resistant. Eg; I have never ever seen Botrytis attack Sophronitis flowers where other species next to them are.


----------



## troy (Aug 10, 2016)

If a flower is not flat and round the plant it's growing from should die anyways


----------



## gego (Aug 11, 2016)

troy said:


> If a flower is not flat and round the plant it's growing from should die anyways



LOL you're something else. problem is they never die, the good ones does.


----------



## phraggy (Aug 11, 2016)

I had a few plants that were limping along nicely in the greenhouse until I decided to put them outside in May and put them back in the greenhouse in Sept/Oct. In this part of the world we do not get seasonal weather we just get weather which is mainly temps between 12c and 22c ( and not many days of the warmer one!!) plus many, many days of wind and rain which has left the plants sopping wet most of the time. I have been amazed how the change has made them grow. No signs of rot but plenty of growth in the crowns with the most impressive growths being the roots. They are literally coming out from all over the place so

 I have put just one pic ( of renanthera ) to show the amount of root growth. The plants haven't been fed for 4 months.

Ed


----------



## Redtwist (Aug 11, 2016)

Ed,
Have you done this successfully with any of your multi paphs? I've been giving mine as much time outside as poss on nice days, but I've been too chicken to keep them out when its more inclement. 
'Seasons don't fear the crown rot!' (But I do.)


----------



## phraggy (Aug 11, 2016)

Redtwist said:


> Ed,
> Have you done this successfully with any of your multi paphs? I've been giving mine as much time outside as poss on nice days, but I've been too chicken to keep them out when its more inclement.
> 'Seasons don't fear the crown rot!' (But I do.)


 I haven't tried this with my multis but I'm going to try this tomorrow with a rothchildianum. Will let you Know how this progresses, or otherwise,over the next few weeks. I can't see this being any different but I love my multis and I have been too' chicken' to try this method but I promise I will do this tomorrow.

Ed


----------



## Redtwist (Aug 11, 2016)

phraggy said:


> I haven't tried this with my multis but I'm going to try this tomorrow with a rothchildianum. Will let you Know how this progresses, or otherwise,over the next few weeks. I can't see this being any different but I love my multis and I have been too' chicken' to try this method but I promise I will do this tomorrow.
> 
> Ed



It will be interesting to see if you notice better/worse/different growth after the change. If it looks good I might be braver!
Chris
Ps. Sure you want to start with the roth? Hope you have a spare just in case


----------



## phraggy (Aug 12, 2016)

Redtwist said:


> It will be interesting to see if you notice better/worse/different growth after the change. If it looks good I might be braver!
> Chris
> Ps. Sure you want to start with the roth? Hope you have a spare just in case





I placed this one outside today and deliberately picked one with the marks on the leaves so that we will be able to identify it as the same plant if the experiment proves to be a success --- or not!!! I will just leave it in the open air with no cover and I will not feed it ----fingers crossed.

Ed


----------



## Redtwist (Aug 12, 2016)

I placed this one outside today and deliberately picked one with the marks on the leaves so that we will be able to identify it as the same plant if the experiment proves to be a success --- or not!!! I will just leave it in the open air with no cover and I will not feed it ----fingers crossed.

Ed[/QUOTE]

Let the experiment begin...
I'd be interested to know to what extent water collects/remains in the crowns on our cooler days.

Out of interest, how much full sun will it be getting there? 

Chris


----------



## phraggy (Aug 12, 2016)

Redtwist said:


> I placed this one outside today and deliberately picked one with the marks on the leaves so that we will be able to identify it as the same plant if the experiment proves to be a success --- or not!!! I will just leave it in the open air with no cover and I will not feed it ----fingers crossed.
> 
> Ed



Let the experiment begin...
I'd be interested to know to what extent water collects/remains in the crowns on our cooler days.

Out of interest, how much full sun will it be getting there? 

Chris[/QUOTE]

It will only be getting dappled sun in the mornings because, as you see in the pic, it will be amongst my Angraecums. Hope it goes well Chris .

Ed


----------



## cnycharles (Aug 14, 2016)

Speaking of orchid nurseries, the former ellenbergers orchid Eden near Rochester ny would spray with physan in the winter anytime they watered. They also kept their plants and greenhouse fastidiously clean. 

In nature, things can grow in wet and etc without breeze because where you see them is their 'sweet spot' where the balance of everything they like is just right. 

I've seen studies in further past that showed that air moving over leaves helped pull material through stomates; also the fresh air changed the stagnant gases from around the leaves and increased health and growth

Water is great for removing fungi from leaves if it's constantly or frequently moving and removing spores. Of course bacteria loves water splashing all over so there has to be something out of balance for the bacteria to invade. I think many of us are not creating the balance in our growing areas and from personal experience I know orchid growers love to try and grow things in conditions the plants aren't used to, even though we know we aren't providing the best conditions


----------



## Redtwist (Aug 14, 2016)

cnycharles said:


> In nature, things can grow in wet and etc without breeze because where you see them is their 'sweet spot' where the balance of everything they like is just right.



Absolutely! Its important to remember that when you see a healthy-looking orchid in nature its only where it is at all because that is a 'sweet spot' that led to it germinating in the first place. No doubt hundreds of others elsewhere never made it to maturity.

One quick anecdote re:nature vs our nurture. 

When I was lucky enough to visit Borneo many years ago, I remember seeing a dendrobium (I think!) every morning on a tree that fell the first night I arrived. It was clearly damaged by the fall, yet in the space of the week or so I was there it put out two new growths, flowered, was pollinated and started forming seed pods! Talk about ideal conditions! Compared to that I think all we can provide for them is various levels of compromise.

Chris


----------



## JAB (Aug 15, 2016)

Cleanliness and a prophylactic approach to pest and disease problems is key in ANY garden!


----------



## Redtwist (Oct 2, 2016)

phraggy said:


> I placed this one outside today and deliberately picked one with the marks on the leaves so that we will be able to identify it as the same plant if the experiment proves to be a success --- or not!!! I will just leave it in the open air with no cover and I will not feed it ----fingers crossed.
> 
> Ed



Hows this outside roth been doing, Ed? Returned to the comfort of the g/house yet, and what growth have you noticed?
Chris


----------



## JAB (Oct 2, 2016)

Do most orchid growers keep a fan moving air 24-7 or just when their is light?


----------



## gonewild (Oct 2, 2016)

JAB said:


> Do most orchid growers keep a fan moving air 24-7 or just when their is light?



Probably more important at night but I run 24/7


----------



## cnycharles (Oct 2, 2016)

Should be all the time. Main Street mike here has vigorous air movement in his greenhouses and it is directly proportional to the high quality of his plants, most of which will be closely inspected by clients in their places of business while they lease them


----------



## Ozpaph (Oct 2, 2016)

24/7 for me


----------



## NYEric (Oct 2, 2016)

24/7


----------



## SlipperFan (Oct 2, 2016)

24/7 for me, too. Except for the moments I am photographing.


----------



## abax (Oct 3, 2016)

Yup 24/7


----------



## JAB (Oct 3, 2016)

Well if Main Street Mike is doing it  
24-7 it is! 
Thanks!


----------



## phraggy (Oct 3, 2016)

phraggy said:


> I placed this one outside today and deliberately picked one with the marks on the leaves so that we will be able to identify it as the same plant if the experiment proves to be a success --- or not!!! I will just leave it in the open air with no cover and I will not feed it ----fingers crossed.
> 
> Ed


This has been outside for around 7weeks but I really should have tried this 'experiment' by starting early May. Anyhow the Roth has been outside in all weathers, heavy rain strong winds and some sunshine. This clone is a very slow grower but the small new growth is starting a new leaf. I can't throw any conclusions, the temp dropped to 5c last night so today I have brought it back into the greenhouse. Here are todays pics:-


----------



## Redtwist (Oct 3, 2016)

Cheers for the update Ed. It might not have been exactly thriving in that space of time, but at least its not deteriorated. And no crown rot.

I've been a bit braver with my multis in the last few months - leaving them out overnight more often. Might be my imagination, but they seem to almost get a mini growth spurt after theyve been out. New leaves on a couple, just like your roth, and a roth I just got seems to be enjoying the treatment (no sulky 'no growth' period after the rehoming.)

Tempted to keep them outside all next summer - if we have one, of course.


----------



## phraggy (Oct 4, 2016)

Redtwist said:


> Cheers for the update Ed. It might not have been exactly thriving in that space of time, but at least its not deteriorated. And no crown rot.
> 
> I've been a bit braver with my multis in the last few months - leaving them out overnight more often. Might be my imagination, but they seem to almost get a mini growth spurt after theyve been out. New leaves on a couple, just like your roth, and a roth I just got seems to be enjoying the treatment (no sulky 'no growth' period after the rehoming.)
> 
> Tempted to keep them outside all next summer - if we have one, of course.



Hi Chris. Hope all goes well for your multis. I do think that the fresh air and rain are a big advantage for all types of orchids. We must keep in touch next year to compare the effects on our plants for this type of culture. Of course in many parts of the world this will be a natural way of culture -- but certainly not here!!!

Ed

Ed


----------



## Redtwist (Oct 4, 2016)

:rollhappy:Good idea Ed - Lets see if these plant really can hack the 'great British summer.'


----------



## Alex (Oct 7, 2016)

Inocuor sounds like an effective product - does anybody know if it's available in Europe?

Ray, would you send it over here?

Thanks,

Alex


----------



## Brabantia (Oct 12, 2016)

Alex said:


> Inocuor sounds like an effective product - does anybody know if it's available in Europe?
> 
> Ray, would you send it over here?
> 
> ...


Here in Belgium we can buy "Vacciplant" (Edialux) It is a product from Goemar (France).The actif product is laminarine which is extracted out of sea kelp. It causes the plant to turn on its own natural defense systems to fight fungal diseases and bacterial infections. 
Ref: http://www.arystalifescience.com/release/Arysta LifeScience Agrow Award.pdf


----------



## Ray (Oct 12, 2016)

Alex said:


> Inocuor sounds like an effective product - does anybody know if it's available in Europe?
> 
> 
> 
> ...





I don't think it's available over there, and I know that international shipping is quite expensive.


----------



## naoki (Oct 13, 2016)

Brabantia said:


> Here in Belgium we can buy "Vacciplant" (Edialux) It is a product from Goemar (France).The actif product is laminarine which is extracted out of sea kelp. It causes the plant to turn on its own natural defense systems to fight fungal diseases and bacterial infections.
> Ref: http://www.arystalifescience.com/release/Arysta LifeScience Agrow Award.pdf



This sounds interesting, I should look into it. Thank you for bringing this up, Brabantia.


----------

