"Therefore, I am thinking that using straight 5:1:1 may not be the best mix for my conditions"

It didn't take you long to figure that out! If you think 5-1-1 is dry wait till you use the gritty mix! That will dry your plants out quicker than a drunk in a juice bar! The fir bark is just like pine, very acceptable.
I'm still experimenting but discovered last year that my mixes with some compost performed better, stayed moist longer, and the plants loved it. No more than 25%, 15 % compost seems about right. What compost? Good question! I plan to try many types this summer. Worm castings worked well last year. But I want to try plain manure compost, and other organic additives like dry molasses. It increases bacterial count in pots, which traditionally have low counts compared to ground soil.
Also better than perlite, or turface is Diatomaceous Earth. it holds more water, yet pores are big enough for plants to utilize water when needed.
Turface hold plenty of water, but water is not available to plants when needed. Pores are too small.
It's hard to find the right size DE. Do not use food grade. I have found that Optisorb is the right size. it is an absorbent you can find at auto supply stores. I get mine at O'Reilly's.
Many people will say I'm way off, but experiment yourself. Find what works for you.
I feel a living breathing environment is much better for plants than a lifeless inorganic one. I also add bacteria to my pots via Biota max, and they need food thus the molasses. It will also feed the plants as it breaks down. I also use mycorrhizae fungi although some are already in Biota max. I add more. I use Mycogrow, but another brand Myco-Grow is not the same stuff, www.fungi.com is the right stuff
These pots are really good btw, the roots can breath! Good luck!

Thanks!
I already bought a bunch of perlite and DE today... I am planning on using the DE for my Citrus and indoor plants in a gritty mix, but maybe I'll use some in the root pouches too (the perlite is a bit cheaper though).
I figure the first few years or so will be experimenting with everything.... actually I will probably always be experimenting to some degree... that is the fun of it!

Btw, does anyone have any experience with Lignapeat?
I can get it at a third the price of the sphagnum, so it is very tempting... but if it doesn't perform similar, than I will spend the extra money and get the sphagnum.

Thanks,
Robin

Here is a link that might be useful: lingapeat

The last couple years I grew all my veggies in fabric pots on bare ground, well, on wire on bare ground, we have gophers. Southern Calif. has no rain and dry winds, I watered a little every morning until everything got good and rooted and then probably only watered every three days, not bad I'd say.

I mixed 5 parts bark, 2 parts Turface and 1 part pumice, that was it. I'm on the other side of the Turface debate, and I really wouldn't call it a debate, there is lots of good info out there, they use a lot of it around here in the sports fields and to grow fields of grass. Hence I used 2 parts in my mix, actually I used 2 parts in my outside gritty mix also. If your afraid to commit to something your not sure of try a couple pots this year and see how it goes. I will say this one thing I think is very important.

Try the recipe as written the first time, if you go adding and subtracting then you really didn't make gritty or 5-1-1, all you did is guess and who knows what you end up with. Once you understand it better you'll be able to mold it more to what you want to get out of it. I started with 6 houseplants in gritty one year and grew the veggies in a potting mix as usual, the next year everything was potted in gritty and veggies in my altered version of 5-1-1. Don't overwhelm yourself, you'll take all the fun out of gardening.

Jerry

I am with Drew on DE. I also bought a bag of OptiSorb from O'Reily's. I like it a lot and will use it in bark based mix. While it has good water retention, it also has good aeration property and it is not as heavy, I think. One cup of dry stuff weighs about 3.75 oz and when soaked double in weight (7.5 oz).

So I think, adding DE to potting mix used in fabric container can help to keep it moist longer. I m also going to do some fabric container planting this year. I am glad I came accross with DE ( OptiSorb = Oil Dri)