Grow Your Own Magazine

I have managed ( with lots of blisters on my hands ) to clear the ground where i would like my raised salad bed, and i have got the timber too.
I was wondering whether i should line the bed, which would stop weed roots creeping in, and if i did what the difference would be as i will only be using it for shallow fast growers like lettuce.
If i do line it do i mix soil and compost to fill????
Any help gratefully received!

Whack down some newspaper or cardboard. Perennienial weeds come from deep places.