Is my greenhouse too hot?
Discussion
It's my first year with a greenhouse, so I'm still learning. I've got a load of veggies in there that I plan to plant out once night are warmer, but some are starting to look a little unhappy. A lot of leaves are looking as though they might be scorched. Is this due to it being too warm, to much sun, or due to some cold nights? It's currently about 26 degrees in there and I don't think it's been above 30 (one window on automatic and we open the other one during the day), and it gets the sun from early afternoon through to the evening.
As an example here's a slightly blury photo of a squash. The courgettes are showing similar symptoms too,

As an example here's a slightly blury photo of a squash. The courgettes are showing similar symptoms too,

It is our first year with a greenhouse too , working from home I get to check it whenever I fancy a cuppa , it is incredibly hot in there during the afternoon .
I have been opening the door and a rooflight during the day , plus watering everything well.
Dahlias have come on a storm in there , I dug them up from the flower bed to see if I had lost any this winter and just boxed them up to give them a good start .
I have been opening the door and a rooflight during the day , plus watering everything well.
Dahlias have come on a storm in there , I dug them up from the flower bed to see if I had lost any this winter and just boxed them up to give them a good start .
We have these on our roof windows. Maybe worth a look for a bit of automatic temperature control ?
http://cgi.ebay.co.uk/BAYLISS-XL-AUTO-VENT-AUTOMAT...
http://cgi.ebay.co.uk/BAYLISS-XL-AUTO-VENT-AUTOMAT...
O've got one window with one of them fitted, the other window is currently manual but I think I might add another automatic opener to it.
I'm thinking I'll paint some shading on the outside to keep the sun off a bit. when Iw as a kid my father used to use a flour and water mix, anyone tried this or are the proper shop bought shading paints better?
I'm thinking I'll paint some shading on the outside to keep the sun off a bit. when Iw as a kid my father used to use a flour and water mix, anyone tried this or are the proper shop bought shading paints better?
It's a 10'x6' with 2 roof windows. As a temporary measure I've painted some of the southern side and roof panes with a bit of tescos value self raising mixed with water. Currently shows 25 degrees in there. Both windows are wide open and I've just opened the door about an inch to see if that draws air through better. If I'm going to leave the door open in the day I'll have to rig up some netting to keep the neighbours cats out.
Edited by RizzoTheRat on Tuesday 27th April 15:00
As I thought, small greenhouses heat up quickly, cool down quickly. Its much more difficult to keep an even temp in them and subsequently plants are much more liable to stress and go to seed early. Seeing as how most veg are quite hardy if you are going to sow in trays then get them outside once they have good growth Lettuce, Beans, Celery, Onions that sort of thing. Of course Tomatoes, Peppers, Aubergines will need protecting still. I know its a pain but you could try moving some of the sensitive stuff outside for the day and if the weather forecast says no frost then maybe leave it out all night. I currently have trays of Peas, Onions, Kale, Cabbage, Celery, Celeriac, Marigolds, Antirrhinums and other annuals outside all the time hardening off and would only bring them in if there is going to be a frost. Definately keep on with the shading ( water based paints watered down are easier to clean off) and get a screen for the door and get it open
Doesn't look too happy does it. If the plants aren't drying right out then it's probably not too hot per se, looks more like too much direct scorching sun to me.
Use paint on the windows to provide some shade (look at old park greenhouses to see how common this used to be) or use something temporary to experiment with. This shading netting would do the trick.
Use paint on the windows to provide some shade (look at old park greenhouses to see how common this used to be) or use something temporary to experiment with. This shading netting would do the trick.
In a pinch net curtains will block out quite a bit of sunlight. They definitely look sun scorched as opposed to overheated. Overheated would normally show as limp spindly plants whereas your's seem to be burnt leaves which would suggest to me too strong sunlight.
ETA, whoever mentioned getting the plants out is right. This time of year a greenhouse should be used just to get small weak plants up to strength for the outside. Later in the year you can extend the season with one but not in spring. Use it to bring up seedlings and cuttings and get them outside as soon as they can.
ETA, whoever mentioned getting the plants out is right. This time of year a greenhouse should be used just to get small weak plants up to strength for the outside. Later in the year you can extend the season with one but not in spring. Use it to bring up seedlings and cuttings and get them outside as soon as they can.
Edited by freecar on Wednesday 28th April 11:28
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