Disease in the greenhouse

Wondering about managing disease in the winter greenhouse. I usually maintain mine 45-50 degrees and have fans, etc. But up here in the PNW, the humidity is almost impossible to control. Does anyone have any recommendations for prophylactically treating for fungal disease, etc? Or do you just wait until you see a problem?

I think Ryan mentioned somewhere that he treats prophylactically for fungus, but I’m not sure where he said it or what he treats with. I’m hoping somebody else chimes in with better info!

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I do believe fungus issues are better treated proactively. Once it’s taken hold, it’s much harder to get rid of.


Had fungal issues last year in the greenhouse with the deciduous (japanese maples mainly)
Here is what I did and will do:
1-Clean and sterilize the greenhouse prior to introducing trees and plants inside the greenhouse.
2-Treat (spray) all trees with lime sulphur following manufacturer recommandations. Deciduous (JM) are not allowed in the greenhouse until all leaves are gone and then treated with lime sulphur.
3-Prior to bud break, they all will be sprayed again with lime sulphur.
4-As the leaves are opening, Will spray them with a systemic fungicide.


Thanks all. @Heliostar- how did you sterilize the geeenhouse?

I should have used the word disinfect rather than sterilize.
What I use is KleenGrow. https://www.pacechem.com/agriculture/kleengrow

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I don’t have a lot of deciduous but will spray all - the schedule/scheme here looks rational. I just watched the last Q& A and RN said to use Daconil on pines, that Mancozeb wouldn’t work on them. I wonder about lime sulfur? So, off to buy some Daconil…
Cleaned the living s#!t out of the greenhouse yesterday and now to start moving things back in. Almost all of my trees will winter outdoors - its pretty mild here in the PNW- except for those that that got any significant work this fall.

When its not freezing, try to keep the greenhouse ventilate. Weed and clean off dead foliage before bedding down the trees for the winter. Periodically check for watering, pests and fungus through the winter. Cross fingers and wait for spring.

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