They are epiphytes in nature. Vanda's do well in baskets allowing the roots to dry out between rains in their natural habitat. I am wondering if your referring to "mud", "mississippi mud" and even so called "dirt", these names are what some orchid growers give for peat-based soil-less potting mixes which include Pro-Mix. Growing in "mud" has its distinct advantages. The main ingredient is these mixes is what we commonly call peat moss which is composed of residues of spaghnum mosses, light brown in color when dry. It should not be confused with dark brown to black "peat soil" which is distinctively marked as peat, Canadian peat or Michigan peat. It does have several advantages, as it decays much slower, retains its aeration over a longer period of time. You can add perlite, styrofoam, charcoal, diatomaceous earth an dother components to the peat in order to improve it areation and drainage. Vanda's is one of the many experiments in growing in peat mixes with positive and negative reviews. Vanda's need to dry out between waterings.