> I am thinking about a raised redwood box to plant a small
>garden in on the side of my house.
> So far I have decided to make it redwood because 1) it takes
>a very long time to rot, and 2) no chemicals to***up my
>organic gardening. Does this sound right?
Redwood sounds fine to me. Leave weep holes/spaces for drainage, for
air to enter, and for expansion... I'd leave an 1/4" space between
boards... when redwood gets wet it expands considerably.
> And, I would like it twenty feet long and three feet wide.
>Three feet so I can reach over and weed the thing with out a lot of
>stretching and stooping. Does this also sound right?
I'd make it 4' wide, you can reach in from *both* sides... also 4' is
a better dimension for dividing standard lumber, less waste. If
you're tall make the bed 6' wide, it's not very difficult for anyone
over 5' 10" to reach in 3'. And there will be many times you'll find
chores easier with you up into the garden, so have a step stool handy
too. I'd make your raised bed as large as you have space, if you make
it small you will be sorry later.
>1) what goes on the bottom? Nothing so water can drain out?
>Do I put a floor on the underside of the box? The dirt (ha ha)
>it will be sitting on is "decomposed sandstone" (like decomposed
>granite, only way, way uglier.) There is no nutritional value
>in it -- everything has to be replaced, amending does not work.
If you can eliminate the sandstone down to soil that would be best.
Some people make a bottom of stainless steel hardware cloth to keep
moles out but I'd not bother.
>2) how tall should the box be? Obviously, the taller, the
>less stooping but the greater expense in filling it. Root
>need some root to grow.
Height depends mostly on your height, but if it's 2' tall or more you
will have plenty of depth for roots. Fill is the least expensive
material, don't concern yourself.
>3) screws or nails? As redwood dries out, nails tend to fall
Obviously screws. Sometimes steel corner brackets are a good
>4) what do I fill it with? Straight compost? or a mixture of
>both? What ratio? (The compose place sells both.)
A mixture of about 80% good topsoil is a good start, depends what you
grow. Compost will continue to decompose so you will need to add more
each year... you may decide to add more topsoil and less compost,
depends what you grow and results.
>Anything I missed?
An ice chest for the cold beer.