[Fishplate42]

...at least it seems that way.

We recently moved from SE London to the North Kent coast. We are about a hundred yards from the sea. Over the past few months we have been slowly re-erecting a couple of greenhouses we brought with us. They are now built and have the glass in place, but no insulation. Yesterday they both got up to double figures (C) on the max/min thermometers.

One was heated in London and never dropped below 9/10C, I did not bother to monitor the other one as it was hardly used in the depths of the winter. I guess the warming effect of the sea must have a significance even though we are looking out to the Thames estuary and the North Sea.

What are the maximum temperatures you are getting in an unheated greenhouse in your area?

Ralph.     

[mumofstig]

Years ago I used to live in North Kent, on the I.o.Sheppey and it only very rarely dropped below zero in the greenhouse and hard frost was also rare.
Here in Ashford, it often does, we get hard frosts, as well - I've had -4C so far this winter in the g/house.
Temperatures can go up very quickly, even in winter, on a sunny day. Last week, there was a rare, clear, sunny day, so I sat in the greenhouse for a coffee and the Vitamin D it was 18C  Lovely!

[al78]

It will be a bit milder right on the coast but if you get a month like December 2010, there is no way your unheated greenhouse is going to stay above freezing, the mean Central England Temperature for the whole month was sub zero.

I have got a data logger which logs temperature every 20 minutes and is currently in my greenhouse. Once I get my thermal battery water barrels filled and the small broken pane replaced I will leave it for a month and then look at how the temperature has varied over that time. It is looking like this winter will be colder than average so it will be interesting to see how much milder it is in my greenhouse. I suspect not much if we continue to get days of zero sun at a time (Heathrow has only had 8.4 hours of sun in January up to the 12th).