+0
Ecuador is almost perfectly placed for growing flowers. The Andes mountains have a wide variety of temperatures along their slopes and the movement of the could Peru Current and the warm Panama current off its shores brings regular rain. Add to this the fact that the country receives many hours of sunshine a day, and Ecuador can grow seasonal flowers of every kind all around the year.
About the 'add' in bold, why the bare form here?
Comments  
[if you] add. It's a common expression.
Grammatically that's right. I read it that way too. But it is already a fact that the country receives many hours of sunshine a day, and therefore the country can grow seasonal flowers of every kind all around the year, right? Why imperative/conditional?
Site Hint: Check out our list of pronunciation videos.
Or do you think actually Ecuador can not grow seasonal flowers of every kind all around the year because in fact the country doesn't receive many hours of sunshine a day? If it received that much of a sunshine a day, then the country can grow them? Is that how you read it? 
You aren't adding anything to the country's conditions; you are adding this fact to the list you've already supplied.
I'm kind of confused, Philip.
Take 'If a car navigation system is added to it, the car can be perfect to me', for example. This means that the car is not perfect to him/her yet, right? 
Students: We have free audio pronunciation exercises.
Add to this the fact that the country receives many hours of sunshine a day, and Ecuador can grow seasonal flowers of every kind all around the year.

To this fact (you please) add...
Anonymous
To this fact (you please) add...

What do you mean, anon? Isn't it basically '(if you) add the fact that ....to this'?