A copy/paste of something I wrote to compare Peat vs. Coir Sphagnum peat and coir have nearly identical water retention curves. They both retain about 90-95% of their volume in water at saturation and release it over approximately the same curve until they both lock water up so tightly it's unavailable for plant uptake at about 30-33% saturation. Coir actually has less loft than sphagnum peat, and therefore, less aeration. Because of this propensity, coir should be used in mixes at lower %s than peat. Because of the tendency to compact, in the greenhouse industry, coir is primarily used in containers in sub-irrigation (bottom-watering) situations. Many sources produce coir that is high in soluble salts, so this can also be an issue. Using coir as the primary component of container media virtually eliminates lime or dolomitic lime as a possible Ca source because of coir's high pH (6+). Gypsum should be used as a Ca source, which eliminates coir's low S content. All coir products are very high in K, very low in Ca, and have a potentially high Mn content, which can interfere with the uptake of Fe. I haven't tested coir thoroughly, but I have done some testing of CHCs (coconut husk chips) with some loose controls in place. After very thoroughly leaching and rinsing the chips, I made a 5:1:1 soil of pine bark:peat:perlite (which I know to be very productive) and a 5:1:1 mix of CHCs:peat:perlite. I planted 6 cuttings of snapdragon and 6 cuttings of Coleus (each from the same plant to help reduce genetic influences) in containers (same size/shape) of the different soils. I added dolomitic lime to the bark soil and gypsum to the CHC soil. After the cuttings struck, I eliminated all but the three strongest in each of the 4 containers. I watered each container with a weak solution of MG 12-4-8 with STEM added at each watering, and watered on an 'as needed basis', not on a schedule. The only difference in the fertilizer regimen was the fact that I included a small amount of MgSO4 (Epsom salts) to provide MG (the dolomitic lime in the bark soil contained the MG, while the gypsum (CaSO4) in the CHC soil did not. This difference was necessary because or the high pH of CHCs and coir.) for the CHC soil. The results were startling. In both cases, the cuttings grown in the CHC's exhibited only about 1/2 the biomass at summers end as the plants in the bark mix. I just find it very difficult for a solid case to be made (besides "It works for me") for the use of coir or CHC's. They're more expensive and more difficult to use effectively. The fact that some believe peat is in short supply (no where near true, btw) is easily offset by the effect of the carbon footprint of coir in its trek to the US from Sri Lanka or other exotic locales. That's the view from here. YMMV Al

Not sphagnum. Probably a Brachythecium sp. Best bet for keeping it alive is maintaining the conditions under which is was found.

You can use it as a component in your own potting soil mix, add to your compost or amend the soil in any planting area. It is especially useful in amending the soil for acid-loving plants like blueberries, rhododendrons, gardenias, camellias, etc. The hydrophobic or water-repelling properties are most often encountered when trying to use peat moss as a mulch, which I wouldn't recommend. Typically peat moss - unless exposed to sun and other drying conditions - already has a moisture component that allows it to be incorporated into the soil without presoaking. But if you think it's too dry, by all means, go ahead and rehydrate.

Concrete is alkaline because it is made with lime. Cedar is on the acid side. Glass is inert so it won't have a measurable pH. You can tell if a rock contains lime by doing an acid test. The pH of other substrates might be determined by mixing with distilled water and testing the pH of the solution. I believe there are protocols for this. Mosses don't have roots but most have rhizoids which may serve an analogous function. They can also have hydroids and leptoids that serve functions analogous to xylem and phloem. There are over 10,000 species of mosses and they don't all have the same cultural requirements. There are two ways one can approach this problem: 1) Identify the moss species and look up the habitat requirements or 2) select species growing on substrates similar to the one you want to grow them on. Means for attaching moss propagules (leaf fragments ect.) only need to last as long as it takes for new growth to become established. A misting system can help with the process. I've seen white glue (e.g. Elmer's) used as well as cloth mesh to hold the moss fragments to the surface. On soil you can just press the lower portion of ramets into the soil. If you get the substrate, light and moisture regime right then the moss should become established, although competition from vascular plants or other mosses can be an issue.