Landscape fabric is good thing to have under any bed.
When you put down you need to cover it with six inches of mulch or
composted material.
This will not eliminate weeds forever but pulling weeds out of six
inches of mulch is much easier than pulling them out of deep soil. The
best part is that the weeds cannot go any deeper than six inches.
The experinenced gardeners that have many more years experience than me
have told me that landscape fabric is worthwhile.
Chuckie in the beutiful north, zone 5 (I can see spring!!)