I've seen some descriptions of building raised beds for access from a
wheelchair. I'd like to build one for use on a deck, but I'm
worried about the weight of such a planter when it's wet and
saturated.

I had been thinking about 4'x2', and about 1' tall. That's only 8
cubic feet, which isn't that much weight dry. Or is it?

A google on the weight of topsoil suggested that 1 cubic yard of
topsoil is about 2500lbs! Its been a while since I've been in school
but isn't a cubic yard still 9 cubic feet? That would make a planter
that's 8 cubic feet pretty heavy indeed.

Filled it with water and it would weigh close to 500lbs. Add that to
the weight of the dirt and That's some hefty weight. I've seen some
other estimates as low as 1600lbs dry for topsoil. That still seems
like a lot for a deck.

Am I missing something here? How large can a raised planter be for
use on a porch or deck?

Swyck