Glasshouse heating

[Rev]

And whats the best and cheapest way to insulate it?

[mescalito]

Easy..if your room isn't already in position that is!

I've used either 3" polystyrene or polyurethane sheets wrapped in black plastic and concreted over- but dug in 3"under the topsoil would do so long as it's sealed tight.It will lose all insulation quality if it becomes waterlogged.

Places like this

sell styrofoam sheets.

Polystyrene would be the go if you can actually dismantle the room then replace it afterwards or even dig inside the room.

I've built quiet a few cool rooms and freezer rooms over the years and found that insulating the floor became integral to maintaining freezer temps to avoid needlessly oversizing cooling equipment and wasting energy(and losing money on call-backs!)

Urathane has around twice the r-factor for it's thickness than styrene which is why we used it mainly for freezer apps.-to maintain minus 18'C for optimum storage and also to keep the healthies' away from my clients!

So to cover todays lesson on thermal-dynamics....

with the ground maintaining a 'fairly' constant temperature (9-14'C??)it either:

a)extracts heat from the environment if it is at a colder temperature than the environment.

or

b)gives up heat to the environment if it is at a higher temperature than the environment.

So as you can see temperature is a measure of heat and not cold(ness) with insulation being the resistance to the flow of heat :D

[Tree]

Thanks Mesc good info to know:) You are right about my glasshouse not having insulation under the floor - just bricks on soil. Putting some under the paving would not be too hard.

One concern is how a film of insulation on the ground, will effect the buildup of molds etc.? How do you recommend setting up drainage for excess water??

For now I should definately put some under the cold effected plants.

Thanks again

[waterdragon]

cloches are used as a hothouse within a hothouse, to trap heat even further, this idea can be taken to extremes by utilising individual cloches(ie cut-off plastic coke bottles etc) over your plants - within the cloche - within the hothouse but one good rise in temps and you may run into probs. these principles are the reasons behind people covering their hothouses in materials with two or more layers - to trap heat. might use some of these techniques soon as i need an early start on the more tender items like tomatoes and pumpkins, time is marching on and the stench of spring is in the air.

[mescalito]

Yeah what WD says..polystyrene for eg is just a whole colony of micro-cloches sandwiched into a panel so in essence the same thing.

It's all about providing as many 'convection' or gas filled speces as possible between the high and low temp areas-to slow the migration of heat or "pressure" like the water from a hose or air pressure from a duct-each always migrate from a high source to a low source for equilibrium.

Delaying the transfer is the key here

Re:One concern is how a film of insulation on the ground, will effect the buildup of molds etc.? How do you recommend setting up drainage for excess water??

When you dig the patch make it bigger than the base-lay a first film of plastic down overlapping the sides by 3" or so and stab a heap of holes in the bottom-lay down some blue-metal aggregate or wood planks-then the plastic wrapped insulation-cover with soil(you are all in pots I presume?).

Make sure the 'skirt' of plastic is above the ground line all the way around to prevent run-in and...that's about all I can think of now.

Whew

[mescalito]

Till then get down to your local supermarkets' loading dock and 'borrow' some used brocolli boxes

cut them up and make bases for your pots to sit on.

You might gain 5' or so on the core temp of the pot which might just help.

Alternatively plant straight into them with a few holes for drainage.

Many an outdoor unit freeze-up was remedied by relocating it from the concrete path to wall mounted brackets a few feet above the ground...

Ciao

[planthelper]

i think it's important to have a wide solid concret pathway all around the glasshouse.

this is so that no weeds can start growing,

utelising all the water and nute's run off produced by the glasshouse. i mean avoid gaps and structual details which will later harbour/benefit weeds.

if for example there are posts for shelves or whatever, the weeds will grow around the posts and will be very hard to remove. but without the posts, you can run the lawnmover over that area...

there is nothing worse, than weeds taking over your glasshouse!!