How can I make my java ferns reproduce?

[Dragon cqzzzzz<]

I have about ten java ferns in my 55 gallon tank and long story short, I want more. With the exception of one root hanging from one leaf, my ferns haven't reproduced since I first got them, months ago. I've read that dying leaves produce plantlets, and that if you cut off a leaf, it will automatically produce plantlets until it dies. I recently bought two ferns that have a couple large leaves for the purpose of reproduction. Even though the leaves have brown spots and are torn, they don't show any signs of reproduction.
Can I cut off some big leaves to make them have plantlets?

[Tolley]

I think its jus the plant.

I have one in my 15g for like over 2 years it jus grows but never reproduces...

Bought 4 new 2 leaved ones for my 40g.. fortnight later never seen so many roots coming of the leaves!!!

[Lady Hobbs]

I bought some java months ago and finally gave up on it this week and dumped it. Not one tiny anything had started (6 months at least) and the leaves I had were black and spotted from day one. Those long brown springs (roots) had been cut back and it ruined the plant. I bought others with the long springers still attached and they are finally taking off but it takes a while and not the plant for impatient people (ME.)