Hi,

I have some tomatoes, aubergines, peppers and chillis sown in my heated
propagator in the greenhouse. I only switch it on at night to keep the
temps at around 18-20C at night.

However, during the day I switch it off but I am seeing temps between 25
and 40C. Is this too hot? If I take the lid of the propagator the temp
drops to 12-18C. I can't be there all day to put the lid on and off, so
I just wondered what would be the best thing to do to get the seeds to
germinate.

Thanks.

--
Mark Allison, SQL Server MVP
http://www.markallison.co.uk

On Mon, 05 Apr 2004 16:05:38 +0100, Mark Allison
wrote:

I have some tomatoes, aubergines, peppers and chillis sown in my heated
propagator in the greenhouse. I only switch it on at night to keep the
temps at around 18-20C at night.

However, during the day I switch it off but I am seeing temps between 25
and 40C. Is this too hot? If I take the lid of the propagator the temp
drops to 12-18C. I can't be there all day to put the lid on and off, so
I just wondered what would be the best thing to do to get the seeds to
germinate.

The ideal germination temperatures for the veg you mention are around
21-27C, so you're dealing with both too hot and too cold. How does the
temperature in the propagator get to 40C in the daytime without the
heat on? Is your greenhouse that warm? It doesn't have an automatic
vent? I don't know whether heat or cold is more detrimental. The cold
will retard germination. Heat may be less injurious.

On Mon, 05 Apr 2004 16:05:38 +0100, Mark Allison
wrote:

I have some tomatoes, aubergines, peppers and chillis sown in my heated
propagator in the greenhouse. I only switch it on at night to keep the
temps at around 18-20C at night.

However, during the day I switch it off but I am seeing temps between 25
and 40C. Is this too hot? If I take the lid of the propagator the temp
drops to 12-18C. I can't be there all day to put the lid on and off, so
I just wondered what would be the best thing to do to get the seeds to
germinate.

The ideal germination temperatures for the veg you mention are around
21-27C, so you're dealing with both too hot and too cold. How does the
temperature in the propagator get to 40C in the daytime without the
heat on? Is your greenhouse that warm? It doesn't have an automatic
vent? I don't know whether heat or cold is more detrimental. The cold
will retard germination. Heat may be less injurious.

The ideal germination temperatures for the veg you mention are around
21-27C, so you're dealing with both too hot and too cold. How does the
temperature in the propagator get to 40C in the daytime without the
heat on? Is your greenhouse that warm? It doesn't have an automatic
vent? I don't know whether heat or cold is more detrimental. The cold
will retard germination. Heat may be less injurious.

Well, I was surprised it got that hot too. This was on a fairly sunny day
with the lid on the propagator and the vents open. When I put my hand over
the vent, I could feel the heat coming out. The greenhouse temp was around
25C at this time. When the sun goes in for a while the greenhouse temp is
around 12-18C during the day. Should I bring all my seed trays into the
house, or should I wait a few weeks and see what happens?

My salad leaves have all germinated, but nothing from the "exotic" tray as
yet.

The ideal germination temperatures for the veg you mention are around
21-27C, so you're dealing with both too hot and too cold. How does the
temperature in the propagator get to 40C in the daytime without the
heat on? Is your greenhouse that warm? It doesn't have an automatic
vent? I don't know whether heat or cold is more detrimental. The cold
will retard germination. Heat may be less injurious.

Well, I was surprised it got that hot too. This was on a fairly sunny day
with the lid on the propagator and the vents open. When I put my hand over
the vent, I could feel the heat coming out. The greenhouse temp was around
25C at this time. When the sun goes in for a while the greenhouse temp is
around 12-18C during the day. Should I bring all my seed trays into the
house, or should I wait a few weeks and see what happens?

My salad leaves have all germinated, but nothing from the "exotic" tray as
yet.

On Mon, 5 Apr 2004 23:14:58 +0100, "Mark Allison" nomail@please
wrote:

(Frogleg wrote)

The ideal germination temperatures for the veg you mention are around
21-27C, so you're dealing with both too hot and too cold. How does the
temperature in the propagator get to 40C in the daytime without the
heat on?

Well, I was surprised it got that hot too. This was on a fairly sunny day
with the lid on the propagator and the vents open. When I put my hand over
the vent, I could feel the heat coming out. The greenhouse temp was around
25C at this time. When the sun goes in for a while the greenhouse temp is
around 12-18C during the day. Should I bring all my seed trays into the
house, or should I wait a few weeks and see what happens?

Let me see if I've got this right: you have a propagator inside a
greenhouse. The heat for the propagator is off, and the vents open.
The temperature in the greenhouse is 25C (sunny day), and the
temperature inside the propagator is 40C. Goodness, what a little
clear plastic will do! Having broiled a set of seedlings with a
similar arrangement (except I had the heat on below the propagator),
all I can advise is keeping a sharp eye/ear on the weather. If it's
going to be sunny and warm, give extra ventilation to the propagator.

As for bringing the trays indoors, that'd be fine for germination.
However, once the seedlings emerge, they need light, and you'd have
the same problem until the plants were large enough to be unlidded in
the greenhouse. Perhaps someone else has better ideas.

On Mon, 5 Apr 2004 23:14:58 +0100, "Mark Allison" nomail@please
wrote:

(Frogleg wrote)

The ideal germination temperatures for the veg you mention are around
21-27C, so you're dealing with both too hot and too cold. How does the
temperature in the propagator get to 40C in the daytime without the
heat on?

Well, I was surprised it got that hot too. This was on a fairly sunny day
with the lid on the propagator and the vents open. When I put my hand over
the vent, I could feel the heat coming out. The greenhouse temp was around
25C at this time. When the sun goes in for a while the greenhouse temp is
around 12-18C during the day. Should I bring all my seed trays into the
house, or should I wait a few weeks and see what happens?

Let me see if I've got this right: you have a propagator inside a
greenhouse. The heat for the propagator is off, and the vents open.
The temperature in the greenhouse is 25C (sunny day), and the
temperature inside the propagator is 40C. Goodness, what a little
clear plastic will do! Having broiled a set of seedlings with a
similar arrangement (except I had the heat on below the propagator),
all I can advise is keeping a sharp eye/ear on the weather. If it's
going to be sunny and warm, give extra ventilation to the propagator.

As for bringing the trays indoors, that'd be fine for germination.
However, once the seedlings emerge, they need light, and you'd have
the same problem until the plants were large enough to be unlidded in
the greenhouse. Perhaps someone else has better ideas.

Frogleg wrote:

Let me see if I've got this right: you have a propagator inside a
greenhouse. The heat for the propagator is off, and the vents open.
The temperature in the greenhouse is 25C (sunny day), and the
temperature inside the propagator is 40C. Goodness, what a little
clear plastic will do! Having broiled a set of seedlings with a
similar arrangement (except I had the heat on below the propagator),
all I can advise is keeping a sharp eye/ear on the weather. If it's
going to be sunny and warm, give extra ventilation to the propagator.

As for bringing the trays indoors, that'd be fine for germination.
However, once the seedlings emerge, they need light, and you'd have
the same problem until the plants were large enough to be unlidded in
the greenhouse. Perhaps someone else has better ideas.


Well, I went out and had a look to see how things were going and several
tomato and chilli plants have now germinated. They must like
temperatures in the 30s and 40s (C). I only sowed them on 31st March and
they have germinated already. I think I have accidentally given the
seeds ideal germination conditions. I haven't seen any aubergines emerge
yet though (they were sown on 28th March).

I think I'll just carry on as I am and switch the propagator on at night
and take the lid of on a sunny day. Seems to work, by trial and error.

--
Mark Allison, SQL Server MVP
http://www.markallison.co.uk

In article , Frogleg
writes
On Mon, 5 Apr 2004 23:14:58 +0100, "Mark Allison" nomail@please
wrote:


Well, I was surprised it got that hot too. This was on a fairly sunny day
with the lid on the propagator and the vents open. When I put my hand over
the vent, I could feel the heat coming out. The greenhouse temp was around
25C at this time. When the sun goes in for a while the greenhouse temp is
around 12-18C during the day. Should I bring all my seed trays into the
house, or should I wait a few weeks and see what happens?

Let me see if I've got this right: you have a propagator inside a
greenhouse. The heat for the propagator is off, and the vents open.
The temperature in the greenhouse is 25C (sunny day), and the
temperature inside the propagator is 40C. Goodness, what a little
clear plastic will do! Having broiled a set of seedlings with a
similar arrangement (except I had the heat on below the propagator),
all I can advise is keeping a sharp eye/ear on the weather. If it's
going to be sunny and warm, give extra ventilation to the propagator.

Is the propagator in the shade or is it in direct sunshine for part of
the day? Id the sun gets on it, then erect a sunshade, as well as all
the other suggestions about extra ventilation.

I always try to sow only a few seeds at a time, so I can have a second
(and third and fourth) try if the first lot don't go.
--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/edward/index.htm