If you want to make your Orchids feel at home then use good Orchid compost and mimic natural conditions as best you can.
There are many proprietary brands available but you could do a lot worse than talk to an expert at a local Orchid show.

Orchids love humidity but hate wet feet so a free draining compost is preferred.
Some orchids are epiphytes that grow on other plants and trees and need to retain enough moisture when the opportunity arises.
All roots need air in greater or lesser proportions and some orchids have roots that grow out of pots into open air. That gives a clue as to what good Orchid compost will be like.
Orchids do not get any real food value from the free draining compost so need dilute feed in with the watering.

Content of Orchid Compost

• Bark chippings which come in differing sizes. For plants with thick roots choose a larger chips, if they are small and thin then choose small chippings.

• Sphagnum moss, bark and  styrofoam mixed is good  for seedlings or very thinly rooted plants. It tends tol dry out quickly so watch the  watering.

• Rock wool  mixed with a little perlite can seem dry on the surface   when very wet underneath and over time breaks down into a hard mass.

• Lump peat and styrofoam is good for Phalaenopsis and those plants requiring a little more moisture retention.

Orchid Compost Tips

• You can buy a proprietary Orchid compost at most garden centres
• Compost breaks down and Orchids need repotting into fresh compost but only every couple of years.
• Put some large crocks of foam at the bottom of the pot to aid drainage and retain air pockets
• Repot just after flowering not whilst in flower.
• Let bark compost soak in water overnight before repotting.
• Thompson & Morgan Chempak orchid growth feed. It is a high nitrogen liquid fertiliser containing plant foods, magnesium and six trace elements to promote growth

Orchid compost is available from Amazon