"peter" wrote in message
...
Hi
I'm planning to build a few concrete block garden beds, probably three
blocks high, ten blocks long at the max, on a concrete floor.
What are the growing mediums better suited to this?
Is it a good idea to waterporoof/seal the inner surfaces?
Do you have to use mortar for a wall three bricks high?
Thanks all
Peter

along with interlocking blocks (gotten at box stores) you COULD use cinder
or concrete blocks, turning them upwards with the holes facing up, and
securing with rebar to prevent movement. A cinder block wall three high
would take a 4 foot rebar to drive thru the whole way. I have edged my
front beds with cinder blocks until I can afford enough of those
interlocking cement blocks (that come in about six colors and three sizes,
the smallest being 8 inches, the largest being 16 inches wide at the back,
and the mid range one being about 12 inches.)

They do interlock, but if I were you I'd secure them with a little liquid
nails dabbed in the center to stick them. The glue will hold and prevent
any seperation. We do this at Lowes when we set up a display with the
locking blocks built onto cement so that the fork lifts and clumsy loaders
and what not won't knock them all to pieces if they bump them. When we
break them down in the winter, we drop them on their edges to cause the
impact to loosen the grip of the liquid nail and release the cement. The
locking block doesn't chip but the impact is forceful enough to get the
liquid nail to release. And that's just because gravity works in our favor.
We've broken a few, but you'd not break them apart.

The cinder blocks are about $1.23 each or for the largest one, $1.64.
Turned upwards and secured with a driven rebar, you can fill the holes as
well as the inside of the bed you're making and if you're stacking on
cement, you can use the pea rock as drainage as the other men have
suggested. I am using both types of enclosures including landscape timbers
which cover 8 foot lengths and as high as I want, but timbers eventually
rot, no matter if they're treated or not. If I ever use a straight timber,
I'll go to the composite material that last's for 75 years if I want
straight edges and high walls. It's called Everlast and is a bit more than
timbers but heck, it'll outlast me.............and probably the house and
surrounding area! g

check the box stores for discontinued patterns on the interlocking blocks.
And see if Depot would sell you slightly chipped blocks. Lowes won't, as
they get 100% credit for them and all their concrete garden stuff like
stepping stones, edgers and the like. They'd rather toss them and get credit
than sell them at reduced prices for people like me who wouldn't mind a few
chips or dings. But discontinued patterns or colors are better. I know I
picked up the red and black ones for 40% off and last year we discontinued a
style that was reminescent of old stone walls in a soft yellow that didn't
go over big. We sold those eventually for 50% off and some gentleman bought
three pallets of them and cleaned us out. He saved a bundle by doing that,
but I can't afford to do stuff like that. I have to do it in batches or
small area's until I get the look I like.

I do like the retaining blocks that lock because they also offer a sitting
spot (or place to put pots) if you go for the 12 inch or 16 inch ones. Just
remember that both the locking blocks that are cement and the bricko or
cinder blocks leech a bit of ph and adjust your soils accordingly. I've lost
a few things planted into the holes that didn't like the "taste" of the ph
and soil once I filled the holes. I think it's more alkeline (? someone set
me straight on this, as I'm not sure if it would be acidic or alkeline) . I
think you'll like either one. I like them both. The cinder blocks for the
ability to secure with a rebar, and the locking blocks for their neat
appearance and more ability to curve (they're fun to fill with soil and
provide pockets for plants to cascade eventually over)
hope this helps a bit more.
madgardener