I grow my tomatoes in a cold greenhouse, I often get white patches on
the leaves, but this year a quarter of my plants are effected.I thought
it could be something to do with the extreme temperature we have been
getting this month.
It is either very hot sunshine or freezing cold.

Any ideas would be gratefully received.
--
Bill P
Shildon
Cradle of the Railways

Hi all.

On Mon, 20 Apr 2015 20:47:12 +0100,
Bill P wrote:
I grow my tomatoes in a cold greenhouse, I often get white patches on
the leaves, but this year a quarter of my plants are effected.

It is powdery mildew, as far as I know.
http://www.tomatodirt.com/powdery-mi...-tomatoes.html
http://tomatodiseasehelp.com/powdery-mildew

Funny enough, I though to plan my tomatoes in a greenhouse to *avoid*
this kind of problem but learn today, that it is „(...) more common in
commercial tomato fields and greenhouses than in the home garden (...)�.

Okay, I know nothing and so does everybody else.

The above referenced pages contain some hints on how to treat the plants
affected by the mildew, but from what I have seen here and elsewhere,
this may work. Or not.

Good luck.

Michael

I thought
it could be something to do with the extreme temperature we have been
getting this month.



It is either very hot sunshine or freezing cold.

Any ideas would be gratefully received.


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On 22/04/2015 10:51, Michael Uplawski wrote:
Hi all.

On Mon, 20 Apr 2015 20:47:12 +0100,
Bill P wrote:
I grow my tomatoes in a cold greenhouse, I often get white patches on
the leaves, but this year a quarter of my plants are effected.

It is powdery mildew, as far as I know.
http://www.tomatodirt.com/powdery-mi...-tomatoes.html
http://tomatodiseasehelp.com/powdery-mildew

Funny enough, I though to plan my tomatoes in a greenhouse to *avoid*
this kind of problem but learn today, that it is „(...) more common in
commercial tomato fields and greenhouses than in the home garden (...)�.

Okay, I know nothing and so does everybody else.

The above referenced pages contain some hints on how to treat the plants
affected by the mildew, but from what I have seen here and elsewhere,
this may work. Or not.

Good luck.

Michael

I thought
it could be something to do with the extreme temperature we have been
getting this month.



It is either very hot sunshine or freezing cold.

Any ideas would be gratefully received.


I have seedlings that went white a day after putting them outside in a
cold frame. I think it must have been the shock because, back indoors,
they're turning green again

stuart noble wrote:

I have seedlings that went white a day after putting them outside in a
cold frame.

Sunscald; put them out with some partial shade for a few days as they get
acclimated to _real_ sunlight.
At one point I got a light meter to determine what my artificial lights
were doing. It was shocking to see the difference between outdoor
sunlight, sunlight in a double-wall polycarbonate greenhouse, and
fluorescent grow lights!

--
Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic
Zone 5/4 in upstate New York, 1420' elevation. NY WO G

On 22/04/2015 14:28, Gary Woods wrote:
stuart noble wrote:

I have seedlings that went white a day after putting them outside in a
cold frame.

Sunscald; put them out with some partial shade for a few days as they get
acclimated to _real_ sunlight.
At one point I got a light meter to determine what my artificial lights
were doing. It was shocking to see the difference between outdoor
sunlight, sunlight in a double-wall polycarbonate greenhouse, and
fluorescent grow lights!


Good tip. Many thanks

On 20/04/2015 20:47, Bill P wrote:
I grow my tomatoes in a cold greenhouse, I often get white patches on
the leaves, but this year a quarter of my plants are effected.I thought
it could be something to do with the extreme temperature we have been
getting this month.
It is either very hot sunshine or freezing cold.

Any ideas would be gratefully received.

Thanks guys.
I am leaning towards sun scald. I have but some white fleece up.
I think it is working, no more white appearing on the leaves that I can see.
That sun has been a bit strong this month.

--
Bill P
Shildon
Cradle of the Railways
County Durham
Landof the Prince Bishops

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