Lining your garden beds with plastic mulch or landscaping fabric helps prevent weeds and preserves soil moisture. Plastic mulch is best for vegetable beds, as it needs replacement each year. Landscaping fabric is more porous and is often used in perennial and annual flower beds as it doesn't require yearly replacement. Whichever you choose to line your garden beds, proper installation is necessary for it to be attractive and to reap the largest benefits from its use.
Loosen the soil in the garden bed and add any fertilizers or soil amendments desired. Level the soil with your hoe so the bed is even.
Dig a 2-inch-deep trench around the perimeter of the bed. Set the removed soil outside of the bed on top a tarp.
Cut a piece of landscaping fabric or plastic mulch to fit the bed with a 2-inch overlap on all sides. Lay the mulch over the bed and push the edges into the trenches.
Fill in the trenches with the removed soil, pinning the mulch down. Alternately, fill with decorative rocks if lining a flower bed.
Cut a 6-inch hole in the mulch for each plant. Trim away in plastic that is touching the plant after sowing, as the plastic may burn the stem if left touching.
Cover the liner with a 2-inch layer of decorative wood chips or rocks in flower beds. Leave the mulch uncovered in vegetable beds, as it will help heat the soil and keep the vegetables clean.