Autovent Lifespans

[Convolvulus]

^^^I am not very knowledgeable in regards to GHs and vents but for what it is worth. My one with the autovent gets silly hot so the auto vent triggers at 18 degrees and I often have the door open. This year I am going to try whitening. As much as toms like the heat they are not fans of stoopidly hot.

Is your GH in sun all day or is there anything to interrupt it i.e. hedge etc?

Mr C.

For tomatoes, I would suggest you want to aim for a maximum temperature around 30-35C. However, my experience is that you can't do that with venting alone, you'll have to shade the greenhouse as well and water inside to use evaporation.

Chillies can stand it hotter.

Again, the issue isn't usually the outside temperature but the amount of sun. My greenhouse is partially shaded by a local oak tree and its at its hotest in May/June when the leaves aren't out fully.

I stand my Chillies in the hottest place I can find.

Thanks for replies.

The GH is on a narrow allotment plot so limited choice in locating it. The door faces approx SE and although there are a couple of big trees to the SW, even now the arc of the sun seems to be above them so even when the leaves are out, it should be in full sun most of the day.

Any advice (or links to advice) on how to shade the GH would be appreciated.

From the junk I had to remove when dismantling the GH, previous owner appeared to have kept reptiles in it at some time so there was lots of (perished) bubble wrap and other insulation intended to keep the heat in. This was held on by plastic pegs which fit into slots in the frame so it would be possible to fit old bed sheets or something similar to the roof section - is this what people do.

Mark P By "evaporation" do you just mean having containers of water inside the GH or something more sophisticated?

Thanks again and apologies, for not starting a separate thread.

Mr C.

[Cadalot]

My greenhouse is covered in debris netting as a form of shading, and on really hot days I have been know to put the hose on the debris netting and cool the Perspex

[Bigmallly]

I used to use debris netting on my plot greenhouse. Some folk use an emulsion wash.

[Convolvulus]

Thanks guys, I've added debris netting to my skip diving wish list.

[bearded bloke]

Another vote for debris netting here

[Convolvulus]

For tomatoes, I would suggest you want to aim for a maximum temperature around 30-35C. However, my experience is that you can't do that with venting alone, you'll have to shade the greenhouse as well and water inside to use evaporation.
…

My greenhouse is partially shaded by a local oak tree and its at its hotest in May/June when the leaves aren't out fully.

Yesterday on a sunny day in mid April, if the Charlie Dimmock branded GH thermometer I bought from £land can be believed (quite a range of temperatures on display in the shop - I chose one in the middle of the range!:roll eyes), the temperature in my GH hit somewhere between 30-35C with the autovent open.

Opening the louvres brought it down to below 30C and the door to 20-25C.

Looks like we are going to keep an eye on this!

[Guest]

^^^ The one thing I would recommend is a min/max therm. I am so glad I got mine. It will give you a better idea of what is going on and when you can put what in there.

http://www.growfruitandveg.co.uk/gra...ion_88528.html

[ESBkevin]

The idea of bubble wrap is to 'double glaze' the greenhouse if you plan on early season seed starting and heating in the greenhouse. I do this and then use a blow away greenhouse as racking and another layer of clear plastic. You can buy a wash to apply inside the glass to aid shade but having bubble and wash is a pain so if you bubble then netting is a favourite.