I would say no, myself... unless you want to screen it further to get the pieces more uniform in size.

This is what my mix looks like... the pieces are all fairly uniform in size, and rather small... about the size of a dime, or so... they aren't wood chips, but are 100% fir bark...

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These are two of the ingredients I use...

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Reptibark tends to get a bit expensive if you need large batches of medium, but I know there are threads here in the forum dealing with where to locate the different ingredients in different areas of the country. A search should net you the exact results you need... I don't have a link to it, offhand.

Perhaps one of our esteemed experts here can help with a link... or perhaps a name brand and a location. Anyone?

Your mix should be fine for orchids and the bark should be various sizes. Best to visit 'Orchids Forum' for further advice. Different type of container growing.

Jane

the bark should be various sizes.

why? What is the advantage to various sizes versus a single, uniform size?

For Al's Mix and the Gritty Mix, uniformity is rather important, as referenced in Al's very educational article, "Container Soils - Water Movement and Retention IX", linked below. The information contained therein is highly beneficial, and an excellent reference source for those who want to learn the "how and why" of container gardening.

I, too, would like to know what the advantages are in various sized bark and wood pieces in a medium... perhaps Jane will regale us with stories of her experiments in the name of gardening science. Jane, if you would be so kind?

Here is a link that might be useful: Container Soils - Water Movement and Retention IX

Depending on the orchid the OP is growing, most orchid roots want to be exposed to air. They have 'drip-dry' roots. Different size bark or stone leaves large air spaces. Most orchid roots would rot if buried in any type gritty or soil mix. Most orchids grow attached to trees and rocks.

Jane

sorry i didn't clarify. i'm using the orchid fir bark to for my blueberry bush. i only bought the orchid mix because i couldn't find fir bark anywhere else.

sorry i didn't clarify. i'm using the orchid fir bark to for my blueberry bush. i only bought the orchid mix because i couldn't find fir bark anywhere else.

It should work fine, but is larger than ideal. All this means is you will need to water a bit more often. If you are OK with that, all is well. When it comes to particle size, it's not just about the length/width, it is also about how the individual particles pack together. Lack of uniformity in shape is desirable and this results in particles that have difficulty compressing together and thus open air spaces result. Jane says: Different size bark or stone leaves large air spaces. Most orchid roots would rot if buried in any type gritty or soil mix.

Different sizes do not necessarily leave large air spaces. Different shapes do. If we were to take particles where half were 1/8th inch squares and the rest were 1" squares they would eventually compact to make a solid block. The smaller squares would simply fill in the spaces between any larger squares. If our shapes are squares, circles, triangles and etc. then they have a very hard time fitting together like puzzle pieces and sealing up air passageways.

The mean size of the particles is important, but once that size is achieved it's more important to have irregular shapes than shapes capable of fitting together and filling in those air spaces.

I thought it was obvious to all that bark is irregular in shape and size. Excuse me for leaving out the word shape. I have never seen orchid/garden bark cut into squares. I guess anything is possible. Would be interesting trying to line them all up like a puzzle, in a round pot leaving no air spaces. You'd need a lot of time on your hands.

No experiments, Jodik, just common sense.

Jane

Common sense for an epiphyte, perhaps... but not all plants like quite so much exposed root, Jane. You are an orchid grower, so you look at things from a different perspective... a very different perspective, judging by your posts.

Blueberries and orchids are very different plants... blueberries are not epiphytic... while it might not be possible to grow a healthy blueberry plant in pure orchid bark, it's definitely possible to grow a healthy orchid in Al's Mix. I've got some planted in it, and they're doing quite well. They'd be doing even better if the winter air weren't quite so dry, but I suspect they'll be thriving once they go outdoors in spring.

None of the arguments here would be necessary if everyone substantiated their claims. But it seems to me that only the gritty mix users offer valid science to back up their claims. Why is that?

Op never mentioned Blueberries. I answered a question about bark size.

Jane, the OP didn't specify BB, but a subsequent post clarified the mix was for BB.