Fixing sleepers

[lightning]

Hello

I am doing raised beds with oak sleepers
I am using the 125 mm base of the sleeper and going 3 high 600 mm

I am using 250 timber lock bolts to secure
Question should I cement in oak post on the inside to secure all 3 sleepers as it’s going to me 7 meter run

Do I have to use oak posts

Thanks Paul

 

[ktuludays]

I normally use standard tannalised 3 x 3 posts postcreted in. As they're inside the bed they're protected from the bulk of the elements.