Cool - I see you made the trip over here. I was going to suggest you drop by, but you left no means by which you might be contacted.

Well, you need a little more than a yard of soil, or about 30 cu ft.
I would use:
24 cu ft pine bark fines ........... $36
3 cu ft sphagnum peat ................. 7
4 cu ft coarse perlite .................. 15
5 lbs dolomitic lime ..................... 3
5 lbs controlled release fert ....... 20 - optional (MG cheaper)
a micro-nutrient source

The layered mix you suggested is likely to present drainage problems & not smell pretty if it does. ;o) This mix will drain well & retain aeration.

Good luck.

Al

PS - It helps if you let us know where you live.

Are these containers 6 feet by 2 feet and 5 feet by 1 foot?
How deep? And what do you plan to plant in them? Annuals? Evergreens? ??

I don't have a balcony, but have you figured out how much this will weigh? Will the balcony hold this much weight?
Just a thought.

Lee

luvstoplant, 3 dimensions were given: 6'long by 2.5'wide by 1' deep. That's a pretty shallow planter and I wouldn't 'think' that it would be too heavy for a balcony, even when wet.

I would assume that annuals would be the plant selection for something like this...or a combination of annuals and small perennials.

Corp...rule, another reason for using a homogenized medium is that layers of completely different stuff can create a drainage problem for you. You want these shallow container to be able to drain quickly of excess water or your plants will be in real trouble.