Insulating a greenhouse - advice sought.

Catweazle · Post by **Catweazle** » 07 Nov 2010, 20:19

Does anyone have any tips ? I have some clear bubblewrap and some of the clips for fixing sunscreen into the aluminium, but it doesn't look like it will make a neat job.

Practical ideas anyone ? I'm trying to keep my Habanero and Scotch Bonnet peppers alive over winter, I have a paraffin greenhouse heater which I'd prefer not to use.

woodburner · Post by **woodburner** » 07 Nov 2010, 21:08

Build a small poly tunnel in the greenhouse, (or a large one over the top). Use plastic water pipe for the hoops.

Keela · Post by **Keela** » 07 Nov 2010, 21:12

Fill two large containers with water and site on either side of the said plants.... to act as a heat store.

If a really cold night is expected then add a couple of kettles of hot water to said containers to help keep ambient temperature (in the mini tunnel inside the greenhouse) warmer!

Good luck

Catweazle · Post by **Catweazle** » 07 Nov 2010, 21:52

I hadn't thought of a poly-tunnel inside, I have some plastic electrical conduit which will make good hoops.

Do you think I could rig it with my bubblewrap ? Or would plain plastic sheet be better ?

Keela · Post by **Keela** » 07 Nov 2010, 21:57

Either would be good.

On a really cold night you could drape fleece over the top too..... Snug as a bug!

Post by **adam2** » 08 Nov 2010, 09:15

In the longer term, it might be worth considering solar heating for the green house.

I have seen one very simple installation that worked well.

A couple of solar hot water panels installed on a shed roof, south facing, a small circulation pump, and a coil of plastic water pipe buried in the soil of the green house.
A differential control operated the pump whenever the temperature in the collectors exceeded the temperature of the soil.

Water as cool as 20 degrees will heat a greenhouse, and this is easily achieved even in winter.
The soil has very considerable thermal mass and therefore maintains a fairly steady temperature throughout winter.

Catweazle · Post by **Catweazle** » 08 Nov 2010, 09:17

I'm not sure about the fleece idea, it would get waterlogged and frozen, also it would help snow stick.

If it gets really cold I can pull some glowing charcoals out of the fire and put a little basket of them out there. A metal container with small air-holes might burn for a long time.

Keela · Post by **Keela** » 08 Nov 2010, 10:51

Catweazle wrote:I'm not sure about the fleece idea, it would get waterlogged and frozen, also it would help snow stick.

Not if it was inside the greenhouse and over your mini polytunnel....

I use fleece on its own inside my greenhouse (in the spring) once my toms in pots move out there to keep a late chill off them.

Catweazle · Post by **Catweazle** » 08 Nov 2010, 11:15

Keela wrote:
Catweazle wrote:I'm not sure about the fleece idea, it would get waterlogged and frozen, also it would help snow stick.
Not if it was inside the greenhouse and over your mini polytunnel....

I use fleece on its own inside my greenhouse (in the spring) once my toms in pots move out there to keep a late chill off them.

Ahh.... I misunderstood you there

I'll have a look for some cheap fleece,

Catweazle · Post by **Catweazle** » 08 Nov 2010, 11:20

adam2 wrote:In the longer term, it might be worth considering solar heating for the green house.

I have seen one very simple installation that worked well.

A couple of solar hot water panels installed on a shed roof, south facing, a small circulation pump, and a coil of plastic water pipe buried in the soil of the green house.
A differential control operated the pump whenever the temperature in the collectors exceeded the temperature of the soil.

Water as cool as 20 degrees will heat a greenhouse, and this is easily achieved even in winter.
The soil has very considerable thermal mass and therefore maintains a fairly steady temperature throughout winter.

The greenhouse has a floor of substantial paving slabs over sand, but I could put some water containers in there and heat them from panels. That sounds like an early spring project.

Post by **adam2** » 08 Nov 2010, 11:50

Catweazle wrote:I'm not sure about the fleece idea, it would get waterlogged and frozen, also it would help snow stick.

If it gets really cold I can pull some glowing charcoals out of the fire and put a little basket of them out there. A metal container with small air-holes might burn for a long time.

Take great care if doing this, burning charcoal is liable to produce carbon monoxide which is very poisionous.
Many people have died from the use of charcoal indoors.
If you do this, vacate the area promptly after after putting the glowing coals in the greenhouse, and ventilate well be re-entering.

the mad cyclist · Post by **the mad cyclist** » 08 Nov 2010, 13:07

I was going to suggest a small-insulated section within your greenhouse, but that’s already been said. Would a hot-bed of loam and horse manure work?

I built a Dick Strawbridge type solar sink under my greenhouse, I’ve got pictures somewhere, I’ll try and dig them out.

One idea I had was to build a new winter residence for the chickens, which would somehow be built onto a small greenhouse constructed out of old double glazing sealed units. The chickens could then provide heat for the greenhouse at the time of year when they’re at their least productive at egg-laying.

Keela · Post by **Keela** » 08 Nov 2010, 13:34

Apparently that permaculture idea (heat from hens) is one that has been somewhat debunked. Or so Patrick Whitefield suggested on a course I attended last year.

sam_uk · Post by **sam_uk** » 08 Nov 2010, 15:16

Keela wrote:Apparently that permaculture idea (heat from hens) is one that has been somewhat debunked. Or so Patrick Whitefield suggested on a course I attended last year.

I heard that there was not many people doing it, and so very little evidence to support the claim.

Chickens definitely give off heat though.. In the very coldest weather I can feel the warmth when I open the door to let them out. So I reckon if you have chickens you might as well give it a go.

Post by **adam2** » 08 Nov 2010, 15:51

Hens and polytunnels seem to be incompatible.
The birds peck holes in the plastic, and may die from eating it.

Dont see why it should not work in a glass glashouse, provided that the birds are not unduly destructive of the plants.

Definition of a chicken "a bird that can not fly for any useful purpose, but which has suprising powers of flight when escaping or destroying cultivated plants"