If you need to create a new garden bed but prefer not to resort to chemicals, try this technique. Lay stacks of 4 to 6 sheets of newsprint side by side on the grass, overlapping edges, to mark the desired shape of the bed. Soak paper with a hose, and cover with 2 inches of mulch. You can plant directly in the prepared area, using a trowel to pierce the layers.
Greener Garden-Bed Prep
Martha Stewart Living, March 2008