Hi, this is my first post to this site, so I hope you will forgive me if this problem has been covered before. Every year the overwintering plants in my unheated greenhouse suffer from grey mould. I make sure that the plants are not too close together and that the greenhouse is well ventilated, although up here in Morayshire most of the air going in is fairly damp. I wondered if there was a spray someone could recommend that might prevent this, as I am a bit wary about using sprays on dormant plants. I tried green sulphur powder last year but it did not have much effect.

In article ,
eptal writes:
|
| Hi, this is my first post to this site, so I hope you will forgive me if
| this problem has been covered before. Every year the overwintering
| plants in my unheated greenhouse suffer from grey mould. I make sure
| that the plants are not too close together and that the greenhouse is
| well ventilated, although up here in Morayshire most of the air going
| in is fairly damp. I wondered if there was a spray someone could
| recommend that might prevent this, as I am a bit wary about using
| sprays on dormant plants. I tried green sulphur powder last year but
| it did not have much effect.

It wouldn't.

In the West Country, houses were (and probably are) built without
room heating, as it was and is largely unnecessary. But they did
have fires and airing cupboards, which used the heat to reduce
the relative humidity. You almost certainly have the same problem.

If you can get power there, occasional (SLIGHT) heating to reduce
the humidity temporarily will discourage grey mould. It won't do
more, unless it is done more-or-less continuously.

Another thing that you could try is a small (ultraviolet) tanning
lamp (e.g. one for the face) and leave it on in various positions,
not too close to the plants. I have no idea if it will discourage
grey mould, but it might.


Regards,
Nick Maclaren.

Thank you for your prompt reply, unfortunately I am unable to supply power to the greenhouse. So I will just have to keep trying to hold the mould at bay the best I can.

Eptal

"eptal" wrote in message
...

Hi, this is my first post to this site, so I hope you will forgive me if
this problem has been covered before. Every year the overwintering
plants in my unheated greenhouse suffer from grey mould. I make sure
that the plants are not too close together and that the greenhouse is
well ventilated, although up here in Morayshire most of the air going
in is fairly damp. I wondered if there was a spray someone could
recommend that might prevent this, as I am a bit wary about using
sprays on dormant plants. I tried green sulphur powder last year but
it did not have much effect.

eptal

Maybe the soil is to damp?? I try to keep most of my pots on the dry side.
Geraniums stand this very well. Which plants do you seem to be having the most
trouble with?

Jenny

In message , eptal
writes

Hi, this is my first post to this site, so I hope you will forgive me
if
this problem has been covered before. Every year the overwintering
plants in my unheated greenhouse suffer from grey mould.

This tends to be a problem with UK winters. Cold grey foggy days are
perfect for fungal spores to germinate and dormant plants are
vulnerable. You may find some species fail more easily than others -
frost will seriously affect most tender plants in a greenhouse so if you
can keep it frost free that will help a lot. So will ventilating on any
"warm" sunny days.

I make sure
that the plants are not too close together and that the greenhouse is
well ventilated, although up here in Morayshire most of the air going
in is fairly damp. I wondered if there was a spray someone could
recommend that might prevent this, as I am a bit wary about using
sprays on dormant plants.

There used to be a smoke that you could use, but it was withdrawn some
while ago because it was effective (ie also dangerous)

I tried green sulphur powder last year but
it did not have much effect.

It wouldn't.

Regards,
--
Martin Brown

I have geraniums and fuschias and I keep the soil as dry as I can , only giving a little water when things are looking quite droopy. It seems to attack the places where I cut back the stems , though again I cut back long before I put the plants in the greenhouse in order to let the 'wounds' seal before I take them in.

Last year I over wintered about 35 geraniums of which I was able to save about 12, and I lost all of my fuchsias.

Having just read what I have written to you it occurs to me that perhaps in letting things get too droopy they are more susceptible to disease.

Eptal

"eptal" wrote
JennyC Wrote:
Maybe the soil is to damp?? I try to keep most of my pots on the dry
side.
Geraniums stand this very well. Which plants do you seem to be having
the most
trouble with?
Jenny

I have geraniums and fuschias and I keep the soil as dry as I can ,
only giving a little water when things are looking quite droopy. It
seems to attack the places where I cut back the stems , though again I
cut back long before I put the plants in the greenhouse in order to let
the 'wounds' seal before I take them in.

Last year I over wintered about 35 geraniums of which I was able to
save about 12, and I lost all of my fuchsias.

Having just read what I have written to you it occurs to me that
perhaps in letting things get too droopy they are more susceptible to
disease.
Eptal

I think I probably prune my geraniums and fuchsias harder than you do. I don't
have a lot of stems with leaves, more twiggy dead looking things !

Pics at : http://eesc.orst.edu/agcomwebfile/edmat/FS1.pdf

Jenny

"Martin" wrote
wrote:
I think I probably prune my geraniums and fuchsias harder than you do. I
don't
have a lot of stems with leaves, more twiggy dead looking things !

Pics at : http://eesc.orst.edu/agcomwebfile/edmat/FS1.pdf

The geraniums that over wintered on my office window ledge remained in
flower and are still in flower in our garden.
Martin

Yes, they will keep on growing indoors, but IMO out in the 'just frost free' GH
they need pruning hard.

Mine are also still outside and flowering. I am reluctant to prune and bring in
until it gets really cold!
Jenny

In article ,
Janet Baraclough.. wrote:

Ideally, at some time during a very cold spell, open all the doors
and vents wide overnight to let the cold kill mould spores. Obviously,
you'd need to put any plants in the house or garage while the GH was
getting the freeze-cure.

Are you sure?

Yes, you will kill active grey mould (Botrytis cinerea) that way,
but I should have thought that its spores would take any temperature
this country ever gets to. This is checkable by finding out its
northerly limit in the wild, but my guess is that it extends right
up to the limit of fruiting plants.

That doesn't affect the relevance of your recommendation, of course,
as there are lots of parasites that ARE killed by cold.


Regards,
Nick Maclaren.