Hi
You can cultivate sphagnum moss yourself. It is easier than to source a person who markets it.
Sphagnum can be very easy to cultivate if a few simple rules are followed.
1. Start with fresh, actively growing cuttings taken from the top 10cm of the plant, below this viability drops off proportionally.
2. Chop these cuttings into segments at least 1-3cm in size. Any smaller tends to over stress the cuttings and reduce regeneration.
3. Use a substrate consisting of good quality peat. If building an outside mini-bog, use a minimum depth of 50cm if possible.
4. Sow at a minimum rate of 1:10 (cuttings taken from 1 square foot are used to "seed" 10 square feet). Coverage rates are directly proportional to sow rates. Ideally, a continuous light layer of quality cuttings would be used.
5. Growth rates have been shown to increase with an initial light covering of mulch. It needs to be deep enough to prevent the moss from drying out, but thin enough to permit light to reach the moss. In larger applications straw has been used successfully. Sphagnum will also benefit from some vascular plants. A commonly cited example is Cotton Grass. All of this improves the microenvironment found at the surface of the peat.
6. Water level is critical for respiration and photosynthesis. Most species of Sphagnum will appreciate an occasional flooding of 3 cm or less. Respiration and photosynthesis levels peak out with a water level of 12cm below the surface. (However, this is for mature cultures in which the sphagnum is over 12cm in height) In new cultures you must maintain the water level at a point that prevents the sphagnum from drying out. Browing of the tips is usually an indication that conditions require a higher water level.
7. Use only rain, distilled or RO water. Sphagnum will not tolerate hard water.
8. Ideal temperature range for most species is 50-70f
9. Sphagnum appreciates a "basin” when getting started; this helps to maintain a more favorable microenvironment.
10. As a rule of thumb, the more colorful the species, the higher the light level required to maintain that color level. (Almost all species can be found in green when grown under lower light conditions)
Sphagnum occurs naturally in true bogs, fens, swamps...etc.
Truly optimal growing conditions will vary somewhat from species to species, as will color, growth rates, Ph levels and so on.
Regards
ashwini