Yeah, it's porous so it does promote drainage as well as give the roots a nice rough surface to grab onto, and it also gives a little weight and stability to the pot, but mostly we use it just because it's fairly cheap and available here. You don't have to use that, though. Sharon's using almost straight coir these days. It's coconut husk fiber that's degraded to the point that it looks a lot like peat. She doesn't add any cinder, and not much perlite either. It seems to drain okay, and doesn't need to be watered as often. Hawaiian Sunshine is a large-scale wholesale producer and their mix consists mostly of coarse-milled peat "substrate", which is very similar to the coir, it's chunky and drains a lot better than the fine stuff. I tried that on some of my plants and it was fine, but the cinder mix costs less so we stick with that. A basic peat-perlite mix is also okay, or you can add bark or any number of other things, just not actual garden dirt.

A basic rule of thumb is if you live in a dry climate go heavier on the peat or similar moisture-holding material, and if you live in a wetter area go heavier on the cinder or components that don't hold so much water. It's not critical, though, because you can adjust your watering schedule accordingly. The most important part of the equation is to just be consistant. If you have a bunch of plants potted in all different mixes some are going to dry out faster than others, and if you water everything at the same time you'll end up overwatering some and underwatering others. Fortunately bromeliads are more forgiving in this regard than most other types of plants, but it's best whenever you get a new plant to unpot it, gently remove most of the soil and repot it in your own mix, whatever it is you're using. If you just buy pups then it's even better, you don't have to disturb the roots.

We use the same mix for pretty much everything-- heliconias, gingers, trees, whatever. The only broms I treat differently are the Crypts, which like it wetter so I give them either straight coarse peat or sphagnum moss. Same for sowing seeds, I use sphagnum.

Lisa thanks, I have my soils done properly then. Some of the bigger plants have lava rocks in the bottoms of the pots for weight and good drainage

Lisa,hdd. I did an experiment with different kinds of mixes,sand,small stone chips,perlite,sph.moss,and fibers,alone, and in various combinations, a few years ago,with Vriesea,Aechmea,and Billbergia.It seemed that it did'nt matter at all to the plants,which all grew normally. It did make the watering schedule complicated tho.I eventually standardized when repotting,but it was interesting to see that broms will prosper under all those various growing mediums. Bob