[kentishlad]

Hi all,
I'm on the ponce for advice again  I have an unheated greenhouse which I used last yaar with mixed results and I think one of the problems I had was baking everything.

The gh has 2 roof vents - 1 works automatically, and a louvre vent at the end opposite the door.

This year I bought a min/max thermometer and plonked it in the gh  to my surprise, even at this time of the year, any sort of sunshine and the t emp. goes over 30, 35 c . today it was mostly overcast and it still got to 25c
Im sure i read somewhere that temps over 30 c is likely to check the growth of plants, is this right? I tried to keep the temp down last year but I know I didnt always remember to open the vents and doors and prob. had temps well over 30, probably like 40

i had sweet peppers that grew, but not many fruit per plant, only 3, 4 max. aubergines that started purple but grew really really slowly and went pale colour, quiet hard and smallish despite plenty of water  // feed. some tomatoes in the soil went well, small plum shape yellow ones did well but some st pierre cordon type were stunted in height but bore some fruit.
Chilli peppers seemed to grow ok though, loads of them!

any tips or advice greatly appreciated.

[yorky]

Hi Kentishlad,
You are right, even on a dull day at this time of year the sun’s rays can make greenhouse temperatures soar. About the end of April I will paint the outside of my greenhouse with a product called coolglass. This is on sale at most garden centres.
You can also fix netting on the sunny side and roof of your greenhouse to filter the sun’s rays. This works best if you can secure it on the outside rather than inside, as once the sun has gone through the glass the damage is done.
Hope this helps,
Brian

[gobs]

Also keep water trays and water the base, humidity helps plants to cope, also it cools a bit.

[noshed]

I ended up taking everything out of mine last summer. I couldn't get up the plot often enough to water/keep it cool.
It's more useful to me now really.

[kentishlad]

Hi,
Do you find the coolglass stuff makes a  significant difference, I think I should try it if it does? Im sure I heard somewhere about using windowlene and leaving that on.

What about temps. do you have a max. temp you try and avoid?

Thx I'll try some trays of water too.

[yorky]

The coolglass does help, as do the water trays for humidity etc. But I think that noshed has hit the nail on the head. If it’s not convenient for you to be opening and closing doors and vents at every change in the weather, then it could be a losing battle in the hottest months of the year.
Incidentally, the smaller the greenhouse the bigger the problem. A large greenhouse has a bigger volume of air so doesn’t fluctuate as much.
Brian

[kentishlad]

I see what you're saying. Sometimes we do go away for a day or two and this is a problem (that and forgetting stuff, lol) but I guess in the summer at least where evening temperatures are higher there is nothing stopping me leaving vents / doors open?
Im thinking Aubergine and sweet pepper plants here, I guess as long as there is no danger of frost a cooler evening temp. of say 5c maybe, wouldn't cause a problem?

[fletch]

I agree with the last comment. Coolglass definitely helps, if nothing else it seems to prevent scorch.
I am lucky in that my plot is across the road from my house so I can check daily. However, last summer if it was cool in the morning and I didn't open the door/windows and then it heated up during the day I would still come home to wilting plants and temps over 30C. And I practically live on site!