[Dane]

The brighter the light the faster it will grow. As long as you have a good light source and keep the moss very damp at all times, spreading it thinly will lead to the best results. For the most part the java I've used has grown very slowly due to insufficient lighting. The only time I had it take off was when I was experimenting with a vert 10 that had a 65 watt CF floodlight over it.

 

[Dane]

It only took about 2 weeks to start spreading rapidly, and I think you should have enough light with 4 cfs. It grows mostly by new shoots coming off of older growth, but eventually you'll see little stalks containing spores growing vertically, and the young sporphytes that these produce help fill in any gaps left by the branching growth.