greenhouse Balcony acting like a nasty greenhouse

So currently im growing 5 cayenne peppers in my balcony everything was fine until maybe 3 weeks ago when they started wilting in the morning towards the afternoon and then they get back to the normal and the leaves are glossy and shinny green.
Here is some information that might be worthy of mentioning for you guys to help me figure out if its the heat that is causing this:
Its a balcony of 3.8 by 1.7ish. its directed towards the east so it gets full sun from 6 am to 12 pm(give or take). The balcony has glass windows and 2 of them are constantly open with mosquito nets(air flows nicely).
Most of the plants are already having green peppers on them and are planted in 12 litter(@4 gallon) pots(i have ruled out some factors like overwatering/underwatering/too much fertilizer) since i treat them differently for a week now to see if its one of those things. 
Now temperature for example today and yesterday the prognosis was around 20 celsius(68F) and inside my balcony it was 40 celsius(105F).
Soil composition is quite underwhelming on these ones 66% universal soil and 33% compost, it drains quite alright although i have bottom and sideholes in the buckets, which are black which might be an issue with the heat. 
Also would it be just the heat or heat+sunlight?
 
Here is a pic on how the plant looks right now(35 C/96 F) direct sunlight should be over in half an hour.  http://postimg.org/image/awv6wuldv/ 
 
I will upload another one in 2-3 hours when the leaves should be back to normal.
 
I will take any ideas/suggestions regarding this, thank you in advance and sorry for the incoherent/rushed post.

Assuming you mean "greenhouse" instead of "balcony"  :  40 Celsius is much too hot ! 

I would water them more. 

 

Sluggy said:

Assuming you mean "greenhouse" instead of "balcony"  :  40 Celsius is much too hot ! 

I would water them more. 

 

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The location of the plants is my balcony but its acting like a greenhouse when the sun hits the plants directly increasing the temperature too much. Would watering them more prevent them from wilting?

The plants will try to cool themselves off by perspiring. Just like people do in the heat. 

But when there is no moisture in the ground, the leaves will become floppy and eventually wilted. 



The conditions you described sound stressful to your plants. 

Good luck ! 

 

You might want to consider a shade cloth to cut back some of the heat on a few of the closed sections of window... Make sure you have a good mulch on top of the soil layer to cut back evaporation and I would set up some 2 litre drip feeder bottles to help keep soil temps lower and hydrate the plants ( Keep these on the shaded side of the plant so the water doesn't boil lol )....
 
Direct sunlight acts like a microwave on foliage with the radiation absorbing into the leaves so leaf temps can be higher than the same ambient temps with no direct light....
 
Black pots aren't great for super hot environments, I now try and use tan brown ones to cut back on heat absorption. you could wrap the pots in white cloth to help lower soil temps... spraying the cloth with water to moisten it would have an evaporative cooling effect for a few hours until it dries out if you leave it a little bunched and loose.
 
Plenty of options... But a drip feeder would be my first point to look into...

KrakenPeppers said:

You might want to consider a shade cloth to cut back some of the heat on a few of the closed sections of window... Make sure you have a good mulch on top of the soil layer to cut back evaporation and I would set up some 2 litre drip feeder bottles to help keep soil temps lower and hydrate the plants ( Keep these on the shaded side of the plant so the water doesn't boil lol )....
 
Direct sunlight acts like a microwave on foliage with the radiation absorbing into the leaves so leaf temps can be higher than the same ambient temps with no direct light....
 
Black pots aren't great for super hot environments, I now try and use tan brown ones to cut back on heat absorption. you could wrap the pots in white cloth to help lower soil temps... spraying the cloth with water to moisten it would have an evaporative cooling effect for a few hours until it dries out if you leave it a little bunched and loose.
 
Plenty of options... But a drip feeder would be my first point to look into...

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The shade cloth how transparent should it be? i mean light should still be able to go through. I always thought plants love direct sunlight(confusing seeing those greenhouses with dim roofs).

kingduckling said:

The shade cloth how transparent should it be? i mean light should still be able to go through. I always thought plants love direct sunlight(confusing seeing those greenhouses with dim roofs).

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Peppers in a hot environment actually prefer partial shade... In a more mid temp zone full direct is good..
 
I would look for something with a 25% block out...  keeping that in mind I would probably go with 2-3 days shaded to one day off rotation to keep your plants hardened and give them some good light exposure.. a wilted plant can be a good thing in moderation.. But it will stop flowers from setting and cause small fruit to drop.
 
Instead of a drip system you could always set up a wick feed or worst case get a nice dish to sit your pot in filled with water however I don't personally prefer this way as if the water doesn't dry out enough you can end op with waterlogged roots lower in the pot.
 
Another thing to remember is while those windows open help to reduce heat its also causing a dry air environment and drying out your plants..  is the air humid or dry where you are ?

I second the shadecloth. I used it myself when I had a balcony grow in yrs past. You can also put down a mat of some sort to help absorb some heat. Hope this helps

humidity is alright im try to see the progression but it looks constant they wilt in the sun and then the leaves look perfect and stiff.

The plants would probably continue to grow well and be fine as they are, but you would expect to have much fewer pods and slower growth.. So intervening will be a good thing.. I would also repot then with a mix that has higher water holding properties. A loose high flow mix is great when you water once a week.. If its every day with wilting, its not going to suit.. Less bark more compost ...

KrakenPeppers said:

 
Peppers in a hot environment actually prefer partial shade... In a more mid temp zone full direct is good..
 
I would look for something with a 25% block out...  keeping that in mind I would probably go with 2-3 days shaded to one day off rotation to keep your plants hardened and give them some good light exposure.. a wilted plant can be a good thing in moderation.. But it will stop flowers from setting and cause small fruit to drop.
 
 

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What materials are the warehouse covers made from? by googling i ended up with polycarbonate but i saw it comes in sheets only but i also noticed that most warehouses wave a film of some kind way way thinner than a sheet.
It looks like polyethene to me, is that correct?

kingduckling said:

 
What materials are the warehouse covers made from? by googling i ended up with polycarbonate but i saw it comes in sheets only but i also noticed that most warehouses wave a film of some kind way way thinner than a sheet.
It looks like polyethene to me, is that correct?
 

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I thought polycarbonate was a solid hard sheet, I use polycarbonate roofing on my hothouse.  I don't know what you have available in your area.. At the end of the day anything that cuts down light will work wether its a tinted plastic or perforated sheet or nylon weave.. Just ask your local garden centre or nursery they will be able to tell you what is the best option to suit your needs.. as some will be made for weather resistance, some for style etc.