As a general rule, bromeliads require an acidic mix that retains moisture yet drains freely & also provides stability. The roots need aeration & will rot out in a tight or boggy mix. There are many ways to achieve this & different growers have their own favourite mixes.
Ingredients commonly used include peat moss, cocopeat, composted pine bark fines (11-20 mm in diameter), coarse sand, perlite, charcoal, small pieces of polystyrene foam, coarse ash & ‘clinker’.
We use 80% composted pine bark fines, 10% cocopeat & 10% polystyrene foam pieces. Ag lime & dolomite are added to reach a pH of 5.5 - 6.0. The pine bark assures good drainage, the cocopeat retains moisture & fertiliser & provides stability, & the foam pieces maintain aeration.
Commercial dendrobium potting mix is suitable & we notice that Bunnings now sell an ‘Orchid & Bromeliads Mix’.
Don’t plant pups too deeply – just to the base of the leaves.