Caring for dwarf lemon tree? I have a dwarf lemon tree that's been planted within the backyard...

I have a dwarf lemon tree that's been planted within the backyard for 3 years now. And in the end three years, it has only produced 2 lemons!
Questions: would it be best for me to replant the tree surrounded by a planter? and if so, what kind would be best? (plastic, terra cotta, etc?) How much light does it obligation and how often should it be watered? BTW, I live in No. California, if it make any difference.
Which plants and/or trees build and store more...
Answers:    No you do not need to do that just prune it purpose cut of some of the branches and it will regrow with more branches and will get bushier, this will increase by 80% more the production rate of your lemons. Don't verbs about the water since mother quality will take care of it by giving it rainfall water. The same goes for the lantern.