I used a regular bag of shredded pine bark mulch from Fleet Farm, the kind folks drop around roses, etc…mixed that 5-1-1 pine-potting mix-perlite, and it seems way too light…stuffed in a depot and watered, its like running water through gravel. I guess I’m concerned my stuff is perhaps way too coarse, and debating either getting better pine bark, if folks feel this is indeed larger than they use, or doing a new mix of 5-1-1-1 pine bark-potting mix/peat-pearlite-hardwood sawdust pellets to provide some smaller stuff in the mix…but first thing: where do other folks get their shredded bark, and is the lawn stuff what you use, or way too big?
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When I have made container mixes in the past (which I assume is what you are doing) I have used repti bark, which is a pine bark sold at pet shops. It is works well and looks nice, although there are many suitable replacements including just a regular fine ground mulch that you could buy by the yard (usually the bagged stuff is not as good as the shredded). I would also highly recommend adding additional organic material as you will not supply the necessary building blocks for the plant without it. You can always heavily fertilize with liquid or slow release fertilizer but this is usually impractical and a pain in the ass.
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Pine bark that has not been thoroughly composted has the undesirable property of absorbing Nitrogen from the water supply and the soil. It is possible to treat it with specific salts so that the Nitrogen is returned to the soil and plant.
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I have chipper/shredder I used make pine bark for pot mix from regular uncolored pine bark mulch. A lot of noise, but it does the job.
Why not just add compost until texture reaches the point you prefer? It will be a beneficial addition to the mix due to colloidal properties that hold nutrients and also by way of nutrients already in its composition that are slowly made available to plants. As long as mix drains adequately there is also advantage in the increase in available water.
I always use compost in my soil mixes for trees- if weight isn’t a problem I use equal parts sand, compost and peat moss. If it is, I substitute sand with coarse perlite.
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Since water holding properties are inversely proportional to particle size, perhaps you could try sifting the pine stuff you have to get a larger % of smaller particles. Then allow the rest to compost down. Like Alan, I use compost (which I also sift). This alone can create a sticky mix (very water retentive) so I wind up using lots of perlite, but pine bark fines are an ideal distribution of particle sizes. That’s the texture we do-it-yourselfers need to come up with. 
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I use pine mulch, they do not sell finings in my area. Works well!
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I think that the ‘fines’ are ground, and the ‘mulch’ is aged or composted which results in smaller particles still.
Some municipalities will compost materials (and sell them to the public) including wood chips. The chips are ground first then usually only aged one season which is enough for that size.
No. That is not universally true for plant refuse or other materials.
Oh Richard, few things are ‘universally true’, so you work with the best rule-of-thumb or approximation that your observations offer.
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… and many readers here do not have pine bark as an available commodity.
LOL, hard to imagine here. I just had 18 tons of pines removed from my side yard and I’m looking at a huge stand of them behind my house. Too bad I don’t have the means to recycle them, LOL.
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So while you work to have pine bark ground into fines, we pursue local green waste chipped into 1 inch diameter pieces. 
When I started using 5-1-1 I just checked nursery stores for pine bark mulch that seems mostly the right size. The mulch produce, as opposed to nuggets or mini-nuggets, seemed close enough. I know Strange’s sells an actual pine bark fines product, though.
I’m generally much more worried about overwatering than underwatering, so the relative lack of retention is a plus for me.
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ok, using compost seems like a much better idea; they give it away free periodically and even bags of it come pretty cheap…
I have found really nice fine pine bark sold as “soil conditioner”.
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I think it might be useful to elaborate on this statement, because, as I recall, humus has similar water holding capacity as clay as they are both colloidal (consisting of very fine particles), but has much more available water for plants then clay because clay holds a lot of water so tightly plants can’t draw on it. Available water, as I’m sure your realize, is all that matters to the plants and the stewards of plants. Go compost- rich and becoming richer in humus.
Anne what are you using Al’s Gritty mix for? Citrus?
As far as big box stores go pine bark mulch from HD is completely different than pine bark mulch from Lowes. The stuff from lowes looks identical to hardwood bark mulch and is dark and shredded. The stuff from HD looks like what most people like in gritty mix. small pea to dime sized chips of lighter colored pine bark. I’ve used them both in mixes. the HD stuff no doubt has better drainage potential while the stuff from Lowes breaks down easily into a good looking dark compost.
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Sorry about the typo I meant fines. I’ve always used pine bark mulch and it works really well. The rest of the supplies for Al’s gritty mix, I buy at Pet. Co.
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