I am going to experiment this year with my mix to try to accomplish these goals:

Reduce compaction

Increase aeration

Keep the weight low

Keep costs low too

Lower water retention of mix vs. Pro-mix only

The ingredients I found semi-local to me:

Co-op Growers-

Pro-mix BX 3.8 cu ft $27.99

Pro-mix BRK 2.8 cu ft $14.99

Coarse Perlite 20lbs $20ish

Coarse Vermiculite 20lbs $20ish

John Deere-

Turface All Sport 50lbs $16.80(think I can do better)

Pine Bark Fines????? I can't find them fine enough so I might use Pro-mix BRK

I am going to mix it up so actual peat will be about 1/4-1/2 of total mix. I mads some tonight and it looks promising. I will take pictures of the mix and raw materials tomorrow. The compaction and weight is already better than fully saturated Pro-mix.

Does anybody want to share some mix recipes that meet my criteria?

This is good composted pine I find here, the company is in Quarryville, PA.

That's just what I need! I was looking at their website and I want to try the cocoa shell mulch as a top dressing too.

Jason ,
I am very interested in what your results are with this experiment.
 Please keep us updated on your findings for the various mixes you try.
The goals you list are the same I'm hoping to acheive as I continually try to improve my basic mix.
Looking forward to your pics and results.

Kerry,
I gave been reading lots of the posts lately and I am going to try a mix that has more pine bark fines in addition to the other ingredients. Also mentioned Pbfs are very cost effective. The turface does mix well into pro mix I was concerned that some ingredients might settle. I have a couple pots done and one of these formulas will be a winner. Will keep you posted.

Hi Jason,

If you have the time, you may want to check out this thread. I know this post was from the GW citrus forum, but it still gives some interesting info on some soil mixes. The main goal of citrus mixes is for it to have good drainage, which is also a same goal for figs too.

Although it did start out as question I had about pine bark, it did end up with some other good info about some mixes too. Who knows, but thought maybe something could be of interest to you in this post. 

http://forums.gardenweb.com/forums/load/citrus/msg0614173514132.html

The cocoa shell mulch is a problem if you have dogs.  They're attracted to it, eat it and it can kill them.  They can't metabolize methylxanthines the way we can so caffeine and theobromine are toxic to them.

Eliminate the Vermiculite.

I stopped top dressing (mulching) my containers after the first year.  The roots would grow into it much easier than the rest of the container. Since it dries out faster than the rest of the container (water moves down and it retains less water to begin with) you end up watering more.  Also the bottom stays wetter which prevents roots from wanting to penetrate the area.  

My new current recipe on trial is:

Licorice Mulch(Couldn't find Pine bark fines and I like what I read)

Pro-mix BX

Chunky perlite

Turface

Chunky Vermiculite(I saw your post James but I have a massive bag in the garage)

Pine bark nuggets at the bottom of the pot to keep the mix from running out since it is so loose.

 Jason ,
How many parts of each ?

What about turface on the bottom and verm up top? That is how they built the Colosseum, with lighter concrete mix aggregates higher up.

@Kerry- I am not sure yet.I did 10 20gallon pots with varied amounts. One thing for sure is I like using mulch or fines and turface in the mix. I think it really helps with compaction and aeration. I am leaning towards 2 parts pro mix, 3 parts fines or mulch, 2 parts turface, 2 parts chunky perlite, and 1 part chunky vermiculite.

@ Brent- The problem was the mix coming out of the big drain holes. I just put a 2 inch layer of Pine bark nuggets on the bottom and that fixed the issue.

As far as turface on the bottom and vermiculite on top, I believe it's too moisture retentive.  The only reason I use turface with perlite is because the turface is a little finer and holds a little more moisture than straight perlite.

I meant mixed in with the other ingredients Jason. Using the vermiculite in the top half only would reduce the amount of compaction that happens as the verm breaks down.

@Brent- I never thought of using two mixes in the same pot.

Me neither! I would try and make them as equivilant as possible, just one with turface, and one with verm. Sine you want to use the vermiculite, and pots dry from the top down usually. Holding more moisture up top would be better than at the bottom at least. 

This is a picture of one of my current formulas. It is 2/3 turface, perlite, and vermiculite. the other 1/3 is pro-mix and licorice bark.

I am still searching for Pine Bark fines in South Jersey.

Still no pine bark fines so I am using cocoa bean hulls instead. My current mix is 1/3 cocoa bean hulls, 1/2 Pro-mix brk, and 1/6 chunky perlite. My other formula dries out too fast and it isn't even summer yet. Plus turface is too expensive and heavy for 100 trees.

Last year I tried using 40% coarse coco coir and 60 percent sheep manure (composted of course) it works well imo but it will dry out quickly.  When it dries out or ordinary watering seems like it would just drain out and it seem to be fine, it re wets quickly and the plants that would wilt when I first started using it after a water in 15 mins you could tell they had water in  them and were no longer wilting, the problem I am finding other than the need for more frequent watering is they are very heavy with all the manure. 

I am going to set up a drip this year but I am thinking of 25-30% coco, 40-50% manure and 25-30% pro mix and I will add dolomite lime this time.

The really good thing about this mix I currently have is that you have to really try to over water it, when the plants are new the bottom can stay soggy but if it is able to drain you could leave a hose on it for hours every day and the roots would still be fine.

@ chivas- I think we are using 2 different things. I am using cocoa bean hulls which are comparable to pine bark fines and you are using coco coir which is the furry stuff on coconuts. Anyways, I think coir is a peat moss replacement. Good luck with your drip this season.

Jason,
I used to be a fan of vermiculite, but not anymore.  It starts off nice and fluffy but compresses so easily that after a couple months you end up with just these slivers of rock that no longer provide aeration or moisture retention.  I have a decent amount sitting in my garage as well.  I will probably use it for starting cuttings, but not for a large pot anymore. 

You say you can find 20 lbs of coarse perlite for $20.  I'm wondering how that converts to cubic feet, and where you get it.  The best source I have found around me (just north of NYC), is Home Depot, where you can get a 2 cubic foot bag of coarse perlite for $17.  I think that 2 cubic feet probably doesn't weigh quite 20 lbs though, so maybe what you're getting is a better deal. 

There is a source in Maryland (I go down there a couple times a year) for the pine bark fines for $5 for a 2 c.f. bag, so that's fairly cheap.  I don't use any peat.  Figure that if I just don't sift the pine bark fines, there will be a lot of fine particles that will have similar properties.  So for me it's the pine bark, perlite, some fertilizer, and some garden lime.  If I find that I need more moisture retention, I will add some peat to my mix, but I don't anticipate that.

So the Perlite is the biggest expense for me.  I would like to find a way to get it more cheaply.

Rob

Ron, what is the name of the place in Maryland? I have been searching my area for fines like Jason with no luck. 

Pine bark mulch at Behnke's.  I went to the one in Beltsville:
http://behnkes.com/website/about-us/hours-a-directions.html

Call Mr. Mulch, he? they? sell bagged fines for $6.89 and mulch for $5. I was paying more locally but am going to make a trip over to Avondale and save a dollar a bag, they might have it at their West Chester site as well. I found pine mulch at Christmas tree shops, near Concord Mall for $2.50, but it has strandy pieces over an inch and plenty of wood so I think I will sift it and compost the large particles for a year.

Mr. Mulch bagged products

Thanks, that place does not seem that bad to get to from me. I'm still hoping to find a closer source... I am shocked at how hard it is to find this stuff.