DIY Network

I wish to build a raised bed around a hill already coverd with landscape. I wanted to use 4x4 posts and 2 1x4's between each post. Some will be at different angles, kinda like a hexagon, but actually 10 posts will be needed. What is the best way to attach the 1x4's to the 4x4's

Handy I am not completely sure of your plan but I might make the following observations and suggestions. 1"X4" will probably not be heavy enough to keep from bowing when there is soil and water behind. You should use PT lumber as regular white wood unless it is treated will eventually rot out. Have you considered using PT 2X4 or deck boards instead of 1X4's for your horizontal pieces. If you use either kind of wood you should use galvanized nails or screws. They make glavanized deck screws in various lengths. By using screws you could easily replace the damage boards later rather easily.

If your 1X4's are less than 12" long they won't bulge from soil pressure. The best place to put the cross boards is on the inside or soil side of the posts. That way the pressure holds the boards in place. Fastening the boards on the outside of the posts will requre frequent reattaching. As long as your 4X4 posts aren't more than a foot and a half tall they'll hold fine.

Any 1 X is not going to be below ground rated and will rot out. Only wood that's 4 X 4 or above is direct ground contact rated. Not even landscape lumber is direct ground rated. That's why you see them rot out over time and eaten up with termites. Any 1, X is not going to be srong enough to stop the bowing, and any 2, X is going to rot out.
Never ever use galvized screws in any pressure treated wood. With the new pressure treated wood being treated with copper the screws will not last a year.
Use stainless steel or the less expencive ceramic coated screws.
If you use a 6 X 6 on the bottom after leveling out the ground, then set a 4 X 4 on top of it making sure it's even with the outside of the 6 X 6 the wall will have a nice wide base to sit on and help stop any tipping and the top of the wall will look narrow once you back fill it and it's never going to rot out or bow.
The corners need to be off set to over lap and 1/2 X 24" rebar needs to be inserted into holes drilled throught the corners and at least one in the middle.