Ray K wrote:
I'm building an outdoor planter box(about 6.25"x6.25"x13 feet)that will
attach to the side of my house. The pine lumber was nominally 1x8,
ripped to 6.25" and with a true thickness of 3/4". How should I select a
screw or nail to attach the 7.75 x 6.25" end cap? I only have 3/4" to
stick the fastener into, which means that there is only 3/8" of wood on
either side of the fastener.

The concern is splitting. Number 7 screws, 1.5" cause splitting, even if
I predrill; #6 screws can work if I predrill everything and am careful
to make the pilot holes perfectly parallel to the face of the lumber.
With about 40 fasteners required, this is tedious.

The original box was held together with 1.5" staples. I don't own a
stapler, but renting one is a possibility. Any suggestions for nail sizes?

Thanks,

Ray

In reviewing some of the suggestions for using glue, I should have
pointed out that all surfaces have been primed with an oil-based primer
(Zinzer) to resist water entry into the end grain. (After assembling the
box, I may give the interior surfaces a second coat of the same primer,
followed by a latex finish coat.) I suppose the primer interferes with
the holding power of glue. I never considered glue as an option.

Also, I don't plan to fill the box with soil, but will use it merely to
hold container plants, so the weight of the box is not an issue and
attaching it securely to the wall is easy.