Hi all,
I have a little experiment going on for a few months no involving growing Fissidens Fontanus on a small piece of coconut via the dry start method. A few months down the line I can say that it is a success as my moss is attached and is starting to sprout new growth in an emersed form.
What I did was I placed a tiny piece of coconut that was moist and lightly pressing some Fissidens on top of it. I then placed no more than 1cm of water on the bottom of this container and closed the container with a lid. I would spray the container every two days to begin with but then I stopped misting. The idea was that the coconut would stay constantly moist due to capillary action from the reservoir of water to the coconut. This will keep the moss constantly moist too, leaving me without having to mist the moss. The fact that the moss was limp due to having grown submersed meant that it would 'stick' to the moist coconut without having to tie the moss, I've never experienced the moss falling off while misting it due to this reason and that I mist at a little distance around 15cm apart give or take.I can't say that I know exactly how long it takes for it to anchor but given time it will.
As for fertilising, I don't do it. This is because I fear burning the moss with the ferts but most importantly I don't believe mosses require a whole lot of ferts. In the wild some of the mosses will grow emersed on rocks and I imagine the moss won't get access to any organics etc until they are either flooded or from rainwater runing down from the banks carrying anything it can bring to the moss.
However, this method in general might be hard to implement on a larger scale and it also depends on the object which it needs to be tied on because it relied on the little water at the bottom of the container and in most cases dry starts don't involved having the substrate some what water logged. In this case if you have room you can try it in a separate container rather than in the tank for the object. The key to this setup is that the object needs to be moist! Rocks are unlikely to work for this as they can't really draw water up.
Foxfish hits a nail on the head in that you can do dry start by keeping the container in high humidity with good temps. But I use this method because I can't provide a warm environment inside the container I'm using to grow the fissidens, so the little reservoir of water suits my needs as I don't want to mist it.
I can try to take a picture of the moss if you want, it will likely be tomorrow.