When to prune a key lime tree?
 

We have a large (8-12 FT) key lime tree that is 3 years old. I pruned it two years ago after the severe winter we had and when production time came around in the summer, there was no fruit. Last year I left it alone and we had so many limes we we were giving them away to friends. The tree is getting very large now and I am uncertain whether I should or should not prune it and if I should, when is the best time of year?

Any suggestions or information would be appreciated...

From what I have read, a good time to prune the tree (sparingly) is when you see the small fruits developing. You can then prune branches that have no fruit or flowers.
You may prune ground suckers at any time.
The recommendation is not to prune these much at all, unless there is damage, or to maintain the height you say your tree is at now. (I don't think they get much bigger, anyway)

Hope that helps.

You possibly trimmed branches (last time) that intended to blossom, so you unknowingly eliminated the fruit for that season.

Key Lime
 

How to Prune a Key Lime Tree | eHow.com

Horticultural Information About Key Limes

How to Get a Key Lime Tree to Bear Fruit | Garden Guides

https://edis.ifas.ufl.edu/ch092

the best time to prune is right after the last fruit has been harvested, and before the new ones are set. i am surprised that you have a key lime tree at all as they are not winter hardy this far north.....are you sure it is a key lime (the fruits are really small)?

I was thinking the same thing. I have thought of trying to grow one, but think the only way would be in a pot that could be moved indoors when it gets cold.