Colder inside !!!

ideally cover the north wall with foil backed bubble or similar in winter to prevent loss via radiation,which will be highest at night.. unless you leave a roof vent open

Not much light comes from the north in winter so you won`t lose much.
You`ll save a lot of heat though as any wind from that direction is usually pretty cool.

The earth floor might be a benefit if its perimeter is insulated as the heat will migrate downwards in summer and upwards in winter.

 

Hi, there! Yes, bubble wrap is on the agenda! I've just ordered miles of it for both greenhouses!
Hans, the red camellia is a pink min azalea! It show how deceptive photos can be! I think I overwatered it, and had just brought it out to recover! It'll go in a bigger pot shortly and its end-destination is a site that is currently like a builders' yard, full of old bricks! Photos to follow one day!

 

Liz, It does pay to insulate everywhere. One thing I have noticed sitting in my bubble wrapped summerhouse/greenhouse is that even when I can hear the wind outside, there are no leaks as the air inside was totally still. Draughts lose a lot of heat and lead to uneven temperatures. A large part of the benefit of double glazing in a house is actually the complete removal of draughts.

There is more to it than just temperature. I sat in my summerhouse this morning at 9 am, with a cup of coffee. The thermometer read 2C (in the shade). But it was very pleasant. My body was receiving the full force of the suns rays, and the air was perfectly still even though it had not heated up yet. Whilst insulation will cut down the heat coming in by conduction and convection, if you are in the sun virtually all the heat comes directly from the sun as radiation. The result being that by 9:30 the internal temperature had risen to over 20C, whilst it was still only 4C or 5C outside.

 

I'm really aware of the temperature fluctuations in the greenhouse, and want to use bubble wrap for next winter. I haven't seen the sort of "thermal bubble wrap" as recommended by Hex - where can you get it Hex? Your reasons for putting that on the N facing wall make complete sense - I just didn't know it existed!
Can anyone advise re irrigation now that insulation and temperature contriol seems to be exhaustively advised on? I've got a little container from2W + E, and am getting water laid on to my g/house - but I want to make sure I give my seedlings. etc the best poss start!

 

Something as mundane as ordinary aluminium foil will act as a radiant heat barrier.

That`s why your roast chicken doesn`t go brown until you remove it..no radiant heat

Insulating the north wall will reduce heatloss by whatever pecentage your northwall is, in respect to the total surface area of greenhouse,which is probably around 15-20%

 

If your seedlings are still in seed trays then the plastic covers are all that you need. Once they get bigger, why not try capilliary matting. This is what nurserys do.

A simple start would be to buy a large tray - you can get long ones that hold 4 seed trays - cost about �£8. Cover it in capilliary matting, which exceeds the length of the tray. And dip the free end into a washing up bowl of water. The water level in the bowl must be below the tray level or all the water could syphon over into the tray.

The capilliary matting can be anything. You could buy it, or you could use an old towel or an old cotton sheet (double or treble thickness). You would have to experiment with the height of the bowl, the material, and the amount of matting going into the bowl. If the system was too efficient you could get too much water.

 

That all makes sense! TA, Hex and Peter S

 

strongylodon - here are the spider plants in the greenhouse as promised!