Bark mixed can be rinsed. The particles move in shipping and rub against each other. Even the pro g/h mixes purchased on site has a bit of that

Clara

I like coconut bark that comes as chips or chunks.
Can be found on the net at some orchid supply houses or herp sites or locally at a pet shop.

Here is a link that might be useful: Info on coconut bark

What do the stones in the mix look like? Could they possibly be diatomite? Diatomite is irregular with rounded edges and often has muted colors. Or could they be ceramic pellets? Ceramic pellets are fairly round and are the color of red clay pots.

Yes, as Clara says, many bark mixes can be rinsed. Stones may not harm the mix. They may retain moisture and provide weight. I often add diatomite or ceramic pellets to my mixes for these very reasons.

The stones are like pebbles that you would pick up in your yard. Some are about the size of a quarter, I almost broke a clay pot when one of them hit it during a potting session once. I do rinse the bark, but the quality of the bark is not as good as it has been in the past. I have considered trying the orchid potting mixes at Lowe's sometimes. But I am leary of it because you can't see in bag to see size of the wood chips. Has anyone used them?

You can do worse than the Schultz mix. If the stones aren't Diatomite (doubtful) they are at least akin to it and function in the same way. I see it as a positive change in the formula. In the Midwest except in a greenhouse, straight Schultz mix could probably benefit from some added sphag moss or CHC.

H

If it is stones like you pick up in your yard that is pretty bad and I would switch. It is not because the stone will cause any problem in the mix. They may help keep the mix open and weigh the bottom down on a top heavy plant. I often use river pebbles (cork or larger size)in the bottom of my pots to keep them from taking suicidal jumps off the bench.
The problem with the stones in the bark is you are buying the bark and could buy stones separately if you wanted. I wonder if the bark mix is sold by weight or volume along the way. Schultz probably contracts out. I wonder if they know.

My potting medium of choice is hydroton pellets. My orchids thrive in semi-hydro.

- Patrick

The rounded pebbles will have no affect on the mix. I don't know if they are incidental or intended. I have made my own orchid mix with a mixture of diatomaite (medium and fine), ground coir, fine charcoal and perlite.
Very much like Aussie Gold but cheaper.

I do not agree that any ole stone will "function in the same way" as diatomite. Besides other qualities, diatomite absorbs water, whereas many stones do not. But as far as providing aeration to the mix, they will both work.

The last year or so, many of the orchids I've bought have had a little diatomite added to the mix. H & R Nurseries in HI apparently did a controlled study with seedlings in a mix with and without diatomite, and found root growth was faster and better in the mix with diatomite.

It is also supposed to deter crawling insects.

I put diatomite on the surface of sphag for phals, so a tiny bit of whatever can leach down into the pot as they are watered. Don't know if it helps, but it's easy, so just in case... You can also mix it into sphag.

I met a woman once who had great phals in pure diatomite, watered exactly once a week. The roots were great, coiled round and round the bottom of the pots.

So I also put a little diatomite in the very bottom of the phal pots, keeps the mix moist, and just in case they miss a watering, gives the roots somewhere to go for a little moisture.

It's quite light for the volume. Expensive, tho.

I use diatomite with perlite in sphag for phals. They grow really well for me. I also spread some on the top of the sphag to keep moisture in a bit longer. However, they grew well in sphag and styrofoam too, so I don't really know how much difference it makes. What the heck---orchids are my only expensive hobby.

Check out the maker of the potting mixes at Lowes. I found some great mixes at HD made by the Sun Bulb Co. You can check them out on the internet.

Schultz calls the material "calcine clay", thats kitty litter to you and me. This implies a very porous structure to the rock, much more like diatomite than the stones one might find in ones yard.

H