Today I am trying out the method Tom Barr recommended for establishing a ground cover before filling the tank with water. I'm using one pot of Glossostigma elatinoides, cut into nodes and planted "dry", in Black Fluorite Sand, with Diamond Black as a lower layer. This is in a 10 gallon tank, with 30 watts of CFL coiled tube bulbs, with good DIY reflectors. I just spent an hour and a half planting the glosso - reminded me of the videos I see of people in Asia planting rice. The substrate is soaked, but no water is visible. Here is what it looks like now. Note that one pot wasn't enough to completely cover the substrate. But, fortunately, I intended to leave a bare area for some Rotala after I fill the tank.
I plan to post pictures as the glosso grows, assuming it does grow. Has anyone tried this and failed?