Bog construction

I am remodeling a log cabin and found I had to replace an antique tub. There are no cracks, or holes. I would like to convert this to an outdoor bog. The tub is 5ft deep. Should I fill in with some rock before peat and sand mixture, or just 5ft deep soil?
Any other suggestions appreciated.
Rob

I have made a mini bog out of a tub ( like 2 feet deep).

I just filled the whole thing up with peat moss..but before that I ran a tube into the bottom. That became the watering spot. So I didn't have to water the top.

If you fill the tub with rocks or something like that...I would think that you would need something to "pull" the water up to get to the plants. Like a cloth or something like that maybe.

Regardless of whick route you go I think that it will be very nice! You have to take some pics when done so we can post them in the gallery.

use some pots upside down with some additional holes. The empty spaceswill hold a a lot of water so you need not to water even during hot and dry summers (in Germany).
Also you can save a lots of peat (up to 70%).

Here a German homepage :
(look at the 2nd picture)
http://www.moorbeet.de/bau.htm

Thanks for the tips. I'll probably set this up this coming spring. I plan to set the tub down 2 or so feet in the soil. I believe this will insulate during hot and cold months. Probably will put alot of pitcher plants in as the yellow jackets are bad out there