It is much more forgiving if you have the space to plant in the ground. The much higher thermal mass and lower surface area of the ground means the roots are able to stay in a cool medium through much hotter weather, keeping the plant cool.
If you buy plants from a nursery they will be covered in pests usually, especially later in the season. It's best to grow as much as you can from seed.
Who knew so many different creatures would find their way up to my balcony :(
Another thing I noticed is how sensitive plants are to temperatures. A couple of days over 35c killed my tomato and severely injured my jalapeno!