Growing Wild Orchids
Orchids have dust like seed that can survive perhaps 5 years or so while dormant in the soil, but, on germination, the seedlings must form a close association with specific soil fungi. This symbiotic relationship continues below ground for 2-3 years, and then also as the young plant emerges above ground, through to flowering, perhaps 6-10 years after germination.
There is no easy way of knowing if your site can provide the right conditions for Orchids. The required fungus is, however, very common. Also, it appears that grassland Orchids establish and grow best in short, open, flower rich swards on poor soils.
Sprinkle the seed finely over the surface of your chosen spot. Allow rain to wash the seed down through the vegetation and into the soil, and manage consistently from year to year with a mid August cut. When flowering occurs, perhaps after 6-10 years, continue with the mid August cut to allow seed set and dispersal.