Hi,

I'm the under-gardener at our house, i.e. I get all the nasty jobs,
and I would appreciate some advice...

We've recently invested in a 10x14 greenhouse that has a cedar frame,
re-inforced glass & aluminium guttering etc. I have run a (protected)
240V supply to the greenhouse.

The north side is close (3ft) from a tall dense hedge, the East is
protected by a timber barn, but the South & West are exposed - we are
on a high hill in Kent. I have insulated with 1200mm wide bubble-wrap
(9mm cell size).

We have a load of tropical plants in the greenhouse - some fairly
hardy orchids, tamarinds, cactii etc.

Now I have some tubular greenhouse heaters - Can anyone recommend a
supplier for a good frost-stat? Will I need a fan to circulate the
heat? Would it be better to buy a small (water resistant) fan heater?
If so, where from?

Am I completely on the wrong track (I'm an electronics engineer, not a
gardener)?

Many thanks,

Mike

Mike Deblis wrote:

We've recently invested in a 10x14 greenhouse that has a cedar frame,
re-inforced glass & aluminium guttering etc. I have run a (protected)
240V supply to the greenhouse.

The north side is close (3ft) from a tall dense hedge, the East is
protected by a timber barn, but the South & West are exposed - we are
on a high hill in Kent. I have insulated with 1200mm wide bubble-wrap
(9mm cell size).

I prefer the wider material. But any insulation pays for itself very
quickly.

We have a load of tropical plants in the greenhouse - some fairly
hardy orchids, tamarinds, cactii etc.

Now I have some tubular greenhouse heaters - Can anyone recommend a
supplier for a good frost-stat? Will I need a fan to circulate the
heat? Would it be better to buy a small (water resistant) fan heater?
If so, where from?

Probably. Otherwise warm air rises and sits in the ridge at the top of the
greenhouse. Some folk double insulate up there to cut losses. My fan
heater was a parasene from a local garden centre. Power was via an ELCB. A
fan stirring the air greatly decreases trouble with cold spots, moulds and
manges.

Am I completely on the wrong track (I'm an electronics engineer, not a
gardener)?

So far so good. If you have room you can cut the heating bill still
further by dividing the blind end of the greenhouse from the door with a
curtain of bubble wrap. That way any drafts from the doors and when you
have to open the door do not take a lot warm air out of the greenhouse.

I kept my heated warm section at 5C and the door end was still just
about frost free.

A friend with some very touchy tropical stuff has a mini greenhouse within
a a greenhouse.

Regards,
Martin Brown

In article , Mike Deblis
writes

We have a load of tropical plants in the greenhouse - some fairly
hardy orchids, tamarinds, cactii etc.

Cacti on the whole are quite tough. They'll accept the very occasional
dip towards freezing if they are bone dry. Some are tougher than others.

Now I have some tubular greenhouse heaters - Can anyone recommend a
supplier for a good frost-stat? Will I need a fan to circulate the
heat? Would it be better to buy a small (water resistant) fan heater?
If so, where from?

There are plenty of greenhouse electrical heaters available from garden
suppliers. We use old storage heaters, because it's what we had
available free. I aim to keep the greenhouse above 45 deg F, but it does
dip below that, though never, so far, below 32.


Am I completely on the wrong track (I'm an electronics engineer, not a
gardener)?

As an electronics engineer, the most useful thing you could do would be
to link up a thermometer in the greenhouse with read-out in the house,
to alert you to those times when your heating isn't quite keeping up
with the temperature outside. Better still, feed the reading into your
computer and fit trends so you get early warning of sudden temperature
dips.
--
Kay Easton

Edward's earthworm page:
http://www.scarboro.demon.co.uk/garden/

You may also want to try solar. Could you put clean, empty drums that have
been used to transport liquid, inside,along the north side and around the
south side of the green house? You could paint them green or black so they
wouldnt be so unsightly, and cover them with wood to make them into a bench
or shelf. Fill them with water once you have them set where they would
gather the most sunlight during the day time. You would be surprised at how
much warmth they will provide at night. Good luck. Dwayne


"Mike Deblis" wrote in message
m...
Hi,

I'm the under-gardener at our house, i.e. I get all the nasty jobs,
and I would appreciate some advice...

We've recently invested in a 10x14 greenhouse that has a cedar frame,
re-inforced glass & aluminium guttering etc. I have run a (protected)
240V supply to the greenhouse.

The north side is close (3ft) from a tall dense hedge, the East is
protected by a timber barn, but the South & West are exposed - we are
on a high hill in Kent. I have insulated with 1200mm wide bubble-wrap
(9mm cell size).

We have a load of tropical plants in the greenhouse - some fairly
hardy orchids, tamarinds, cactii etc.

Now I have some tubular greenhouse heaters - Can anyone recommend a
supplier for a good frost-stat? Will I need a fan to circulate the
heat? Would it be better to buy a small (water resistant) fan heater?
If so, where from?

Am I completely on the wrong track (I'm an electronics engineer, not a
gardener)?

Many thanks,

Mike

"Mike wrote in message

We've recently invested in a 10x14 greenhouse that has a cedar frame,
re-inforced glass & aluminium guttering etc. I have run a (protected)
240V supply to the greenhouse.

The north side is close (3ft) from a tall dense hedge, the East is
protected by a timber barn, but the South & West are exposed - we are
on a high hill in Kent. I have insulated with 1200mm wide bubble-wrap
(9mm cell size).

We have a load of tropical plants in the greenhouse - some fairly
hardy orchids, tamarinds, cactii etc.

Consider cutting your greenhouse in half with bubble wrap, using strips
hanging down in the middle as a door, effectively making two greenhouses.
The one furthest to the door can be heated to a high enough temperature for
the tropicals allowing air flow to keep the other normally unheated end
above freezing for the more hardy inmates like the cacti (provided they are
dry).
Seen that done with Orchids, hot end for Phaleanopsis etc, and the cool end
for Cymbidiums (which need cold but not freezing night temperatures to
initiate flower spikes).

A "normal" electric fan heater with internal thermostat would probably work
OK, it has for us for years, but if you want more control then a separate
greenhouse rod thermostat would enable that, they are widely available from
good garden supply co's.
Perhaps a second "backup" fan heater in the cool end set at "frost free"
might allow peace of mind.
Fans are always a good idea in a greenhouse anyway, just enough movement to
get the leaves slightly moving is great and will avoid many problems with
plant health associated with greenhouses.
--
Bob
http://www.pooleygreengrowers.org.uk/ about an allotment site
in Runnymede, fighting for its existence against bureaucracy.