Building project advice sought ?

[Drdogface]

We have a large circle of ground/plants/trees etc, in front of our home which is held in by a retaining wall made previously of Redwood boards screwed onto 4x4 posts in the ground. This has lasted for nearly 20 years but is in need of replacement. The project was started about thee days ago, old boards torn out, posts as well and posts were replaced by pressure treated 4x4's in concrete. The boards we bought at a local mill which mills almost exclusively yellow cedar which is cheap and great quality. This time, however, the boards (mostly 2x12) are green.

I fear that if we lag screw them to the posts in this green condition they will eventually split..especially if we use 3 lags on each end. One option would be to just attach them to the posts with one lag screw until they shrink and settle but then there's the risk of warpage. My next thought was to drill out the holes in these boards to a larger diameter than the lags...maybe use a washer on the head of the bolt...and let them settle with that extra room of the larger holes. A mod of this would be to attach at the bottom, but at the top of the board cut a slot to allow the board to settle. Pics are below so you can see what we're doing. The green 'paint' is copper green which will slow down the decay.

Am I on the right track or is there a better way to prevent warp and splitting ?

[sc_rufctr]

Looking good.

I think this is your best option.

"My next thought was to drill out the holes in these boards to a larger diameter than the lags...maybe use a washer on the head of the bolt...and let them settle with that extra room of the larger holes."