Well, yes, it uses at least one fertilizer for every crop thing in its range immediately.
But even once they're all fertilized it goes though fertilizer stupidly fast. You need a pretty high output scrap generator to even think about keeping them fed for more than a couple hours.
If you want to keep it fed at all do a skeleton farm for bones and use a few mining turtles as cobblestone generators for keeping the recycler fed. You can also use an autocrafting table to make the scrap.
This thread is half a year old!
And so is the latest IC2 version. 
And to my knowledge the bug has still not been fixed: as soon as the chunk with the Matron is unloaded and then loaded again, all crops in that area will be fertilized again, draining huge amounts on input.
