Alternative material for growboxes

Hello

I just sided my house last year, and although it is a great siding,
properly sealed with paint, it is very limbre, flexible, easily
broken with hands. Its 1/4" thick and a cementatious mixture- no
hazards like creasote, in my research prior to use. However, I think
it softens with water exposure, yet rehardens as it dries out,just my
observation on some scrap left in the yard during rains. With any
backfill pressure at all, I would reinforce with stakes no less than
12" and meybe wven a lateral stiffener. It is not easy to repair if
it breaks, so would have extra pieces saved to shim any breaches.

I would not recommend it without some extreme support, in which case
it perhaps could last a long time.

My favorite, in the mountains of NC is Locust wood, which is one of
the cheapest woods to buy here, and will outlast cedar, redwood.
walnut, and treated pine by double. We have fence posts still or
nearly as viable and strong as they were put in 60 years ago. The
barbed wire has been replaced many times, and where it was attached
to trees, especially at corners, they are dead center of 40 and 48"
trees, yet the stakes with remnants of the old wire are still
standing. Many have been lost to downed trees etc. but some are still
there, and as solid in the ground as out. We have exterior decks,
that my grandfather had assembled with 5/4" locust rough sawn-green
nailed decking. The standard 2X 10 joists of redwood and then treated
have been supplemented 3 times for the ones still remaining, as the
owners love the weatherd, yet sturdy nature of the locust. Its a much
superior alternative if you can get it. (its yellow locust- don't
know how the other verieties do