top growth "flushes" are part of the trees life, they are often unpredictable. I had trees that did the same thing and once I got all my ducks in a row, so to speak, they all took off. My naval orange has had 2 flushes this year and 2 of my lemon seedlings and my grafted key lime always have new growth on them, so it could be the type.

Now in your case it is really hard to tell what could be going on, because we dont know much about your tree.
what is the soil made of
how much light does the tree get
what are you using for ferts.
how often do you water

Im assuming this one is in a container, and if so Al wrote a very informative post about limiting factors in container plants.

Here is a link that might be useful: How plant growth is limited.

Give it 10 to 14 hours of Direct sunlight in any open field or greenhouse all summer and winter, and you will see it take off, even without much fertilizer..

The sad part is that many of us can not provide that much light all year long or the prerfect conditions.

Some of mine will just rest for months, or seem like they are in supended animation, that is just the way they can be, while others will grow every month..

If it is green and healthy, then I would be apt to think it is more of a light issue than a mix issue...If you were having yellowing leaves, leaf drop, dead branches, fungas gnats, and salt build up in the mix, then soil would have to be adressed almost immediately for best results first, the lots and lots of sunlight..

How much sun does this plant get anyway? Other than the growth being slow, are there any other problems it deals with? Can you post a picture of it? How often does it spend outdoors and where so you put it? Where do you place it come winter in your home? How much sun does it get then? What kind of mix are you using? I am going to assume that your mix is very well draining and pourous...

Mksmth has provided a GREAT link to Al's thread that I know will give you much insight as it has me..

Mike