I wouldn't recommend compost as a significant fraction of any container soil.
You might be able to add 1 part compost to 5 parts bark, plus 1 part Perlite to make a decent mix.

Josh

ani_t, I would use the material as starter for composting. I visualize 6 or so raised beds, filled with a 1:4 mixture of the material to regular soil; allow it to process, turning as needed and then planting your choice crops therein.

I couldn't agree more.
Turn that compost into raised bed gold.

Josh

I concur, as well... compost is wonderful stuff for outdoor gardens and raised beds, but is not a stable choice for container use.

For container growing, see the article/thread entitled "Container Soils - Water Movement & Retention XV".

Here is a link that might be useful: Container Soils - Water Movement & Retention XV

Thanks for your replies. I don't think I can make a raised bed. The little sunshine I have is on the driveway and on a steepslope, hence the container idea. So I guess I would be using this to make a really large container garden!

greenman,
Your recipe mentions bark... where do I get such a large quantity of bark ? and the parts is by volume correct ?

Also, once the containers are spent, can i mix the remnants into the garden soil, ie., will perlite harm pollute my yard.
thx!

You would find bark at a garden center, nursery, landscaping yard, possibly a big box store.
In Washington, there should be copious bark available. You want to find bark in the size-range from
dust up to about 1/2 inch. I use Greenall brand Micro Bark, and I pull the largest pieces out.

The parts are by volume....whatever measurement you choose, whether cups or gallons, et cetera.

Josh

Ok I've been reading the link about Perched Water and water movement etc! Spent almost all day alternating between running builds and checking out posts. Looks like I have my work cut out for me. A pity I bought a big bale 3 cu ft of peatmoss yesterday.... looks like I need to find the gritty mix thing. I am convinced gritty mix is the way to go for containers after seeing so many people swear by it!
But the first order of business is the compost to get rid of. Since the premise of the gritty mix is to not have any microorganisms etc., I can see why compost would be plain silly adding to it.

But I suppose a 5:1:1 mix could use some compost ? I did not see too many indepth threads about 5:1:1 mix... please enlighthen me with links to your favorites.

Thanks!

ani, I use 5:1:1 for a lot of my houseplants and the gritty mix for succulents.

It's 5 parts fine bark (sifted to get out the big pieces and the dusty pieces), 1 part peat moss, and 1 part perlite.

From what I understand, the peat moss portion is interchangeable with compost. For some of my plants, I used leftover MiracleGro potting mix as the peat portion of the 5:1:1.

When you say "horse manure compost," do you mean it's pure horse manure that's been aged?

ani t ,
These might be worth checking out for the sub irrigated container option :http://figs4funforum.websitetoolbox.com/post/subirrigation-containers-and-figs-5112306?highlight=duane
and http://figs4fun.com/bills_figs.html
On the info on Bills Figs he has a picture of a great plant dolly he builds to move these fairly large sub-irrigated pots.
The soil mix in these pots needs to wick moisture up from the resevoir inside , so your peat moss and compost would be very useful as part of your mix.
I use these for figs and for veggies and my mix is an organic equivalent of Pro-mix with a little extra coarse perlite and compost.
Best,
Kerry

Ani,
that's exactly the recipe (5-1-1) I mentioned in the first reply.
The "peat fraction" can be substituted with compost, potting soil, coco coir, et cetera.
Basically, you just need 1 part fine material to help "bind" the bark and the perlite.

5-1-1 works exceptionally well in outdoor containers.

Josh

What about turning the top part of that steep slope into a terrace, or terracing steppes? It would take some work... digging and leveling, then firmly installing the wood or whatever you determine was the best material to hold the terrace area in place. But once done, you'd have a permanent spot in the sun to grow a nice little garden.

Google or search GW for terracing ideas... just a thought...