I do mostly Cinderblock Gardening and I use Squarefoot principles (kind of) and I plant all of my veggies as close to the concrete as necessary to maintain my spacing (in other words) the block wall is not a part of the equation, in the perimeter I plant whatever is small enough to grow in them,ie... onions,garlic, lettuce...etc ...not potatoes etc...

Check out ALL of my videos (they are only a minute each ;-)

Here is a link that might be useful: Garlic Bed Cinder Block

I generally put them at half the plant spacing from the wall. If they're supposed to go on 1' spacing, that's 6".

That said, my walls are 12" tall, so they are pretty high. Planting right on the wall would cut the root-run nearly in half for that plant. Shorter walls provide better access to deeper soil and could allow closer spacing.

Another thing to consider is the plants overhang. If you have a 2' path between beds and plant peppers 3" from the edge of the two beds, you won't have room to walk when they are full grown.

promethean_spark's "1/2 the normal plant spacing" works for me as well for most things.

A couple of points to keep in mind: (1) the concrete will absorb and retain heat longer so while some plant roots will benefit from that extra heat in the early spring, it can be a plant killer in mid-summer. Plan accordingly.

(2) If you plant tall things like tomatoes and peppers or corn near the outside edge it makes it quite difficult to reach the middle of the bed for care and harvesting. Plan to keep the tallest items in the center of the bed.

Dave

Thanks for the replies.

Ok, since the bed is so narrow I don't really have a problem with reaching in and I don't really have the issue of them overhanging but the heat that Dave mentions is definitely something to consider.

@promethean: What do you mean the root run is cut in half with taller walls? My bed is 2 blocks (16") high and there's ok soil below that too, are you saying that would allow for planting closer to the wall?

@JonHughes: Great setup!