Polyethelene Greenhouse Colder Inside Than Out?

[rhyswales]

Hi
I bought a walk in greenhouse a few weeks ago from homebase. The daytime temps inside the greenhouse get into the high 30's so all is fine here, but in the night when the temperature outside is around 15, inside the greenhouse it dips to around 10. Not sure why this is? Yet if i leave the greenhouse door open overnight the temps will remain the same as it is outdoor?

So the temperature is warmer if i leave the greenhouse door open overnight than if i close it, very confused.

http://www.homebase.co.uk/en/homebas...enhouse-265184

Thanks

[Bigmallly]

Hello & welcome to the vine Rhys. It would also confuse me.

[Potstubsdustbins]

Is your out door hi/lo thermometer in direct sun first thing in morning i.e. before you get to see it. This would distort the reading by at least 5 degrees.

The night temps round here have been hovering at about 10' for the last fortnight.

[Bill HH]

Is your out door hi/lo thermometer in direct sun first thing in morning i.e. before you get to see it. This would distort the reading by at least 5 degrees.

The night temps round here have been hovering at about 10' for the last fortnight.

I agree with that.

[rhyswales]

Hi thanks for the reply's, thinking about it, it is in the sun and that could be the reason. Didn't even think about that. Is it normal then for the temperature to be the same inside this greenhouse as outside?

Thanks

[Hazel at the Hill]

No idea, matey - but thought I should extend a welcome to you.

I'm guessing from your user name that you are residing in the principality? You are in the good company of a number of excellent growers.

Oh, and Veggiechicken.

[gardening_gal]

Hi Rhyswales and welcome from me too.

The temps inside your greenhouse will be very similar (if not the same) to those outside at night.

I have one of the cheapo eBay green polytunnels and I have a temp sensor inside and outside it. The inside one usually reads maybe 1C higher (at most) than the outside sensor. My tunnel is a lot larger than your greenhouse though, and will have a larger volume of warm air left over from the daytime sun, whereas a smaller area will get cooler quicker so it's entirely possible your temp inside and out will be the same.

[rhyswales]

Hi all, thanks for the replies everyone.

Was a sudden gust of wind a few days ago and the rubbish blowaway greenhouse decided to make a break for it taking my tomato plants with it. Wasn't best pleased as you can imagine .


I was looking at this greenhouse can anyone tell me this looks any good to them, I'm a newbie at this as you can tell.

Aluminium Greenhouse 07 - Green with Polycarbonate

Also is it best to put a few concrete slabs down as a base to put the GH on (even though it comes with a base) or can i put it on level soil.

Many thanks

[rhonsal]

You might need to consider how windy the site is - my neighbour is always running down the street chasing polycarbonate panels on a windy day as they seem to just pop out (entertaining for me, but not so good for the plants)!

As i saw what they went through on windy days i opted for a greenhouse with toughened glass and have not had any problems!

[Bill HH]

It looks pretty good to me for the price. You will need to be pretty handy to put this up, I am quite skilled but had a bit of a nightmare erecting a similar one. The instructions on mine were rubbish. It is all down to the angle iron/ally, the instructions were not clear as to which way round the angle faced and I found myself having to do things again a few times. I think the instructions were written by a dyslexic china man. Yours may well be better. Make very sure the base is level, if it leans just a couple of degrees it will stress the structure and eventually fall apart. Also of course make sure it is help down WELL. Wind creates tremendous forces on a thing like that as you know. As for the floor mine is on slabs because its on my patio area, everything is in containers, I like it like that. Putting it directly on the soil could cause corrosion. The twin wall polycarbonate is good, mine is just single sheets and I have had a couple blow out as they flex in the wind. Whatever size you go for you will wish you had gone larger so get the biggest you can afford. I haven't found the need for vents because its in my garden and I open the door every morning. Good luck.

[Potstubsdustbins]

I have no idea about that particular make but I do have a 6 x 8 polycarbonate GH that I have been very happy with for over 4 years.

My advice would be to firmly fix the poly glazing with good quality silicone as you build. And yes I would also put down a slab/concrete base, the ground fixings that came with mine were totally useless and you will only realise how light the structure is when you have built it. Wind and sail come to mind.

[rhyswales]

It looks pretty good to me for the price. You will need to be pretty handy to put this up, I am quite skilled but had a bit of a nightmare erecting a similar one. The instructions on mine were rubbish. It is all down to the angle iron/ally, the instructions were not clear as to which way round the angle faced and I found myself having to do things again a few times. I think the instructions were written by a dyslexic china man. Yours may well be better. Make very sure the base is level, if it leans just a couple of degrees it will stress the structure and eventually fall apart. Also of course make sure it is help down WELL. Wind creates tremendous forces on a thing like that as you know. As for the floor mine is on slabs because its on my patio area, everything is in containers, I like it like that. Putting it directly on the soil could cause corrosion. The twin wall polycarbonate is good, mine is just single sheets and I have had a couple blow out as they flex in the wind. Whatever size you go for you will wish you had gone larger so get the biggest you can afford. I haven't found the need for vents because its in my garden and I open the door every morning. Good luck.

Hi Bill, funnily enough a friend of mine said the exact same thing a few months back about instructions, said they were basically useless and it was more guesswork. Yeah I think it's best to clear some space on the patio and put it on there. Just purchased the greenhouse to be delivered tomorrow so lets hope it all goes well, but from what you've said and some of the reviews on the instructions, I will probably still be putting it up this time next week

[rhyswales]

I have no idea about that particular make but I do have a 6 x 8 polycarbonate GH that I have been very happy with for over 4 years.

My advice would be to firmly fix the poly glazing with good quality silicone as you build. And yes I would also put down a slab/concrete base, the ground fixings that came with mine were totally useless and you will only realise how light the structure is when you have built it. Wind and sail come to mind.

Hi potty, didn't even consider using silicone to fix in the glazing. Will definitely have to do that, I believe its quite lightweight, so hopefully will keep the glazing intact for a little longer

[Potstubsdustbins]

All I can tell you is it worked for me. The only time I lost a panel was when my son stumbled whilst lifting a fence panel, his derriere pushed one out.

Bill's right the single glaze panels are much more susceptible to blowing out.