# Rots and temperature change



## Alex (Jul 10, 2017)

I have noticed that I see a much increased incidence of brown rots (bacterial or fungal, not quite sure) when the temperature changes. This could be Winter or Spring, or just when we have a very hot spell like the last few weeks here.I think I've seen passing references to this before, but nothing firm. Is it a a well established phenomenon? Any idea as to the mechanism? I could hazard a guess but that's all.

Thanks,

Alex


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## Ray (Jul 10, 2017)

I suspect that the changes don't "cause" outbreaks, as much as they might place undue stress on an already weak specimen, making them unusually susceptible.


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## ehanes7612 (Jul 10, 2017)

Ray said:


> I suspect that the changes don't "cause" outbreaks, as much as they might place undue stress on an already weak specimen, making them unusually susceptible.



agreed...orchids in general do fine in temperature changes and many require a temperature differential in a particular season to initiate buds (just like many other plants)...if your plant is experiencing rot...then the most likely cause is chronic stress, the temperature change (and probably change in humidity) was just the last straw that made the conditions perfect for rot..I have killed off half a collection before because of chronic stress (and the ensuing rot)..I never get rot anymore..and I place some plants outside during two week periods that receive 20 degree differences in temp (from their original spot) to initiate buds..never get rot


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## Ozpaph (Jul 11, 2017)

I find rot is much more prevalent in hot weather. I think the temp somehow makes the plant more vulnerable.


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## JAB (Jul 11, 2017)

I believe folks tend to over water in the summer (thinking the plant needs more) thus these problems show their true colors... as it were


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## Stone (Jul 12, 2017)

Alex said:


> much increased incidence of brown rots (bacterial or fungal, not quite sure) when the temperature changes. . Is it a a well established phenomenon?
> 
> 
> 
> Alex



Absolutely it is. Perfectly healthy plants can be affected very quickly. More so after temperature drops with me. If you water brachys for example just before a chill - and that can be 15C when they have been growing at 20 to 30, they can rot in 5 seconds. When hot, it's probably a different set of organisms causing the problem but I believe it is closely linked to lack of air movement then along with high humidity. You must assume that the pathogen is always there so avoid sudden temp changes if possible - especially drops. Sometimes it just takes a couple of hours of coolness (plus wetness) followed by warmth again to trigger it. Water by itself can in no way cause rot.


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## My Green Pets (Jul 12, 2017)

Too hot, it'll rot; too cold, it'll mold.

Sent from my SM-J327V using Tapatalk


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## Ozpaph (Jul 12, 2017)

CambriaWhat said:


> Too hot, it'll rot; too cold, it'll mold.
> 
> Sent from my SM-J327V using Tapatalk



LOL


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## emydura (Jul 12, 2017)

Ozpaph said:


> I find rot is much more prevalent in hot weather. I think the temp somehow makes the plant more vulnerable.



I agree Stephen. Heat and high humidity results in a greater risk of rot. I think pathogens are more prevalent in these conditions.


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## blondie (Jul 13, 2017)

I grow all mine in a greenhouse in the summer I find I get less rot and fungi on phrags and paphs. Yet I do fine te other orchids in have do seem supseptable to it. I have a lot more e ventilation in summer due to the doors and Windows being open and very hot days the fans come on. 
But in winter I get less air movement the greenhouse takes long to dry out, so it more humid ripe for fungal and bacterial heaven. With the phrags and paphs being kept wetter I find more so on pheags that they get rots. But I have now grow pheags in trays of water and found I don't really get much rots now.
Yet some of the rots are my fault for not being more care full on watering. 
But with the reforb the greenhouse drys out a lot quicker, so I should be better off but time will tell this winter.


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## Alex (Jul 14, 2017)

Thanks all, very interesting. Like Blondie above, I do also get quite a bit of mould and small superficial rot spots in Winter, but not much substantial. I tend to put this down to constant high humidity and wish there was some way of bringing this down in my small greenhouse...


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## blondie (Jul 14, 2017)

The only way really is to increase the air flow but that can be hard with out fans. Or enough not to dehydrate or make the greenhouse to cold.


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## MattWoelfsen (Jul 15, 2017)

Fans running intermittently 24/7 has encouraged my house-grown orchids to thrive.


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